case study of a child with mild intellectual disability

Case Study of a Child with Intellectual Disability

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In this intellectual disability case study, the author looks at designing an education curriculum for Meagan, a 14-year-old student.

Introduction

There are numerous interventions that have been designed to enable students with intellectual disability better cope with their condition. Most of these interventions have been hinged on the principle that respective educational programs should be tailored to complement the students’ strengths, and to supplement their weaknesses.

This is the same principle underlying the functioning of the K12 educational principle because it is centered on meeting individual student needs (K12 Inc. 2011, p. 1). The K12 educational paradigm mostly works through online communication but it has been seen to offer a lot of advantages to students with unique disabilities.

For instance, the educational methodology is known to provide rich, challenging and engaging content; an individualized learning plan; a learning coach; and cutting-edge technology in the provision of the best learning outcomes for intellectually disabled students (K12 Inc. 2011, p. 1).

When educating students with intellectual disabilities, it should be understood that, students are bound to have trouble in learning, retaining information and understanding information (Pearson Education Inc. 2011, p. 2).

Educators have often experienced such challenges, but comprehensively, there is a consensus among most stakeholders that it is vital to make accommodations for certain groups of students, and it is also crucial to make curriculum modifications for other students. In this regard, there seems to be a lack of consensus in coming up with one formula for handling students with intellectual disability.

This is the main framework for the advancement of this paper because this paper focuses on developing curriculum adjustments for a young man, Meagan. Meagan is 14 years old and has had a history of intellectual disability. This paper analyzes various dynamics of Meagan’s life, with the intention of making curriculum adjustments to provide an effective framework for learning.

To provide a good backdrop for the development of a good framework for learning, several aspects of Meagan’s life will be analyzed. These aspects include his family background, personal history, personal skills and personal abilities.

These factors will be analyzed systematically. Comprehensively, this analysis will be done with the aim of identifying one long-term aim or objective of the learning outcome and two short-term aims or objectives of the learning outcome.

Family Background

Meagan is the eldest child in a family of three children. His younger sibling is a girl, Sophia, aged nine years old. The youngest child is also a girl and she is three years old. Among his siblings, Meagan is deemed to be the child who has experienced most difficulty in learning. Meagan’s family hails from a middle-class society in Melbourne, Australia. His father works as a retired engineer in a local factory.

The mother works as a librarian in a local university. There has been no vivid or confirmed reports of intellectual disability among any of Meagan’s family members, though there have been unconfirmed reports of mental illness among some of Meagan’s relatives hailing from his father’s side of the family.

His aunt is said to experience occasional episodes of mental instability. However, there have been no confirmed reports of mental illnesses or cognitive disability from any of the family members of Megan’s mother.

Megan’s family professes the Christian faith, though they are not committed in their religion. However, Christianity has had an influence on Meagan’s life because he strongly identifies with his Christian faith. In the past couple of months, Meagan was baptized and currently devotes most of his time to his religious duties. None of Meagan’s family members pay much attention to religion.

His family also hails from a background of child neglect, with many of Meagan’s relatives having been abandoned by their parents at an early age. Meagan’s parents are no exception. The degree of attention they give Meagan is inadequate because little attention is paid to Meagan’s slow intellectual development. This has been going on since his parents confirmed that he was suffering from intellectual disability.

There is also an almost non-existent family support structure for Meagan to cope with his condition. Moreover, there is very little evidence of family cohesion among Megan’s family members, starting from his parents to his siblings. In this regard, Meagan is left to live with his condition, alone.

Personal History

Meagan hails from the aboriginal community of Australia. He was prematurely born because he was birthed at only seven months into his mother’s pregnancy. During his infant life, Meagan was abandoned by his mother, even before he was completely weaned from her. This forced his father to look for a baby sitter.

Nonetheless, despite these challenges, Meagan lived to have a vibrant childhood, with no signs of failing to cope with his playmates or friends. To a large extent, Meagan has been deemed a “normal” child. In his teen years, he used to participate in church activities (for the young) and also took part in school activities including extracurricular games.

He was a vibrant member of the school choir and an active member of the school soccer club. However, Meagan’s repeated the seventh grade level (twice) because he failed to meet the minimum threshold for admission into the eighth grade.

For a long time, he experienced a lot of difficulty trying to meet the minimum threshold for admission into sequential class grades because he always trailed among the last five candidates in any class. This was witnessed from his admission into the first grade.

However, Meagan’s academic background was characterized by exemplary performance in various academic writing competitions. His teachers termed him as a very creative writer and he never disappointed in his English creative writing assignments.

However, this was as far as his academic excellence stretched. Currently, Meagan undertakes blue collar jobs on minimum wage but there is increasing pressure among his peers for him to continue with his studies.

Personal Skills and Abilities

Meagan has a creative mind. He has shown interest in creative writing from his younger years but as he grew older, his interest changed. However, as explained in earlier sections of this study, in his young years, Meagan used to write exemplary creative works. His interest however shifted into music when he grew a little older.

So far, he has been able to record music in a local music company but his talents have never been fully exploited because of the lack of adequate finances to bankroll his musical ambitions. Moreover, there has been limited support from most of his family members in his quest to pursue music. However, due to his strong religious background, Meagan hopes to produce music for his local church.

The main aim of undertaking a curriculum adjustment for Meagan is to enable him to earnest his abilities and use them to the optimum benefit of his talents.

To enable Meagan to be independent and able to communicate his needs in effective and acceptable ways.

To assist Meagan to excel in personal growth and compete with other students in varying levels of excellence.

Curriculum Adjustments

Making the best curriculum adjustments for Meagan entirely depends on the nature of his disability. From previous sections of this paper, we have affirmed that Meagan suffers from a slow comprehension of academic disciplines, but he has a stronger grasp on creative works.

Here, there are several curriculum adjustments that can be done to ensure Meagan lives to his full potential. In this regard, this paper proposes several curriculum adjustments, based on the K12 teaching model which aims to provide individualized learning for students with intellectual disability. They are outlined below:

Interest and Student Ability

To ensure Meagan lives to his full potential, it is crucial to make curriculum adjustments to suit individual needs, abilities and preferences. A uniform curriculum which is meant to work for the majority student population is bound to fail for Meagan because it will not be specific to Meagan’s abilities and potential.

In this regard, it is therefore crucial for the curriculum to be designed to emphasize on creative works, as opposed to academic excellence, to enable Meagan to succeed in arts (Queensland Government 2011). Emphasis should be further made to ensure the school grading criteria focuses the same level of attention it gives to sciences (and other disciplines) as it does with art subjects.

Such a grading criterion would ensure students are assessed on all fronts, and not just academic. When adjusting the learning curriculum, it is also crucial for teachers to structure the curriculum in a manner that guarantees the grouping of students into different ability groups.

Not all students have the same type of abilities and therefore, it would be beneficial for teachers to group Meagan into the “creative works” group, so that he can share his creative ideas with his peers (Foreman 2009, p. 170).

Adjusting the Learning Outcomes

Adjusting the learning outcomes is an important adjustment to the learning curriculum if the school grading process is to be fair. Here, “fair” means to accommodate intellectually disabled students (Snowman 2011).

Accommodation of Diverse learning Styles

Intellectually disabled students are normally faced with the challenge of failing to comprehend learning instructions as fast as other students do. However, research studies affirm that some of these students prefer certain learning styles in place of others (Queensland Government 2011). Moreover, educationists have shown that certain learning styles are more effective for intellectually disabled students, while others are not.

Such dynamics withstanding, it is crucial to make curriculum adjustments that allow for the accommodation of diverse learning styles for improved efficacy in learning. For instance, conventional or online lessons can be administered using various learning materials such as DVDs, CDs, Books, videos and such materials (Browder 2011, p. 332).

The inclusion of such diverse strategies is set to improve the level of interaction between the students and the teachers because an appropriate learning style would motivate the students to pay more interest in the learning process. This improves the students’ level of engagement. Moreover, such curriculum changes ensure the learning process is rich in its contents.

Integrating a Learning Coach (Parent Involvement)

It is crucial to integrate the input of a learning coach into the school curriculum to encourage the participation of Meagan’s parents in his educational endeavors. The parents will be the learning support team.

Already, we have established that Meagan hails from a family that pays little attention to his educational needs. Here, there is a strong need to integrate the parents’ input into Meagan’s educational projects to ensure he enjoys a support structure, aside from the traditional teacher-student framework.

Though an integration of the role of the learning coach into the school curriculum may not necessarily be confined in the parent-student framework, it is crucial for this integration to be developed in this framework, if Meagan has to develop better learning skills (National Parent Teacher Association 2009, p. 1 ) .

This is because a great degree of the deterioration of his intellectual ability comes from a lack of effective support structure that enables him to improve his learning skills (Queensland Government 2011).

For long, this need has been ignored, and as a result, Meagan has continually performed poorly in his academic endeavors. Nonetheless, the learning coach framework can be designed in various ways. For instance, the school curriculum can be designed to include the participation of parents in the student’s projects, at least once or twice a semester.

Parents may be required to give consent, provide counsel or similar activities on the student’s tasks, thereby encouraging him to better develop with his learning activities. The inclusion of this principle into the school curriculum may be indirectly beneficial to Meagan because it is bound to have a motivating effect on him. This is the first strategy that can be adopted in encouraging parent participation.

The second strategy that can be adopted by the school is implementing a family-school partnership policy where parents and teachers agree on a common framework where parental involvement is assessed, and the parents’ progress is measured (Westwood 2011, p. 15).

This recommendation emanates from research studies which have shown that schools which have an efficient family-school partnership perform better than schools which lack this policy (Queensland Government 2011).

Finally, the school should make adjustments to the curriculum to ensure that parents take part in the decision making process of activities affecting student achievement. Here, parents should be allowed to be part of advisory committees which affect student achievement.

This paper proposes that, adjustments in the school curriculum which have to be made to accommodate Meagan’s skills and abilities have to be done within the confines of earnesting his skills and abilities (to use them for the benefit of his personal growth). In this regard, this paper proposes that the school curriculum should be tailored to accommodate Meagan’s artistic skills.

Moreover, the learning outcome should be adjusted to accommodate the same skills and abilities. From a holistic perspective, this paper also proposes that diverse learning styles should be accommodated into the learning curriculum to ensure students with intellectual disability learn in an efficient way.

These recommendations are carved from the K12program. Nonetheless, this paper also puts a lot of emphasis on the importance of incorporating parent input in the school curriculum. Integrating these principles will go a long way in enabling Meagan to earnest his strengths and use them to the optimum benefit of his talents.

Browder, D. (2011) Teaching Students with Moderate and Severe Disabilities . New York, Guilford Press.

Foreman, P. (2009) Education of Students with an Intellectual Disability: Research and Practice (PB). New York, IAP.

K12 Inc. (2011) How a K12 Education Works . Web.

National Parent Teacher Association. (2009 ) Enhancing Parent Involvement. Web.

Pearson Education Inc. (2011) Teaching Students with Special Needs . Web.

Queensland Government. (2011) Intellectual Impairment – Educational Adjustments. Web.

Snowman, J. (2011) Psychology Applied to Teaching . London, Cengage Learning.

Westwood, P. (2011) Commonsense Methods for Children with Special Educational Needs . London, Taylor & Francis.

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This Clinical Report was reaffirmed October 2019.

Intellectual disability, global developmental delay, highlights in this clinical report, chromosome microarray, screening for inborn errors of metabolism, genetic testing for mendelian disorders, male gender, genetic testing for nonspecific xlid, boys with suspected or known xlid, female gender and mecp2 testing, advances in diagnostic imaging, recommended approach, the shared evaluation and care plan for limited access, emerging technologies, conclusions, lead authors, american academy of pediatrics committee on genetics, 2013–2014, past committee members, contributor, comprehensive evaluation of the child with intellectual disability or global developmental delays.

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John B. Moeschler , Michael Shevell , COMMITTEE ON GENETICS , John B. Moeschler , Michael Shevell , Robert A. Saul , Emily Chen , Debra L. Freedenberg , Rizwan Hamid , Marilyn C. Jones , Joan M. Stoler , Beth Anne Tarini; Comprehensive Evaluation of the Child With Intellectual Disability or Global Developmental Delays. Pediatrics September 2014; 134 (3): e903–e918. 10.1542/peds.2014-1839

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Global developmental delay and intellectual disability are relatively common pediatric conditions. This report describes the recommended clinical genetics diagnostic approach. The report is based on a review of published reports, most consisting of medium to large case series of diagnostic tests used, and the proportion of those that led to a diagnosis in such patients. Chromosome microarray is designated as a first-line test and replaces the standard karyotype and fluorescent in situ hybridization subtelomere tests for the child with intellectual disability of unknown etiology. Fragile X testing remains an important first-line test. The importance of considering testing for inborn errors of metabolism in this population is supported by a recent systematic review of the literature and several case series recently published. The role of brain MRI remains important in certain patients. There is also a discussion of the emerging literature on the use of whole-exome sequencing as a diagnostic test in this population. Finally, the importance of intentional comanagement among families, the medical home, and the clinical genetics specialty clinic is discussed.

The purpose of this clinical report of the American Academy of Pediatrics (AAP) is to describe an optimal medical genetics evaluation of the child with intellectual disability (ID) or global developmental delays (GDDs). The intention is to assist the medical home in preparing families properly for the medical genetics evaluation process. This report addresses the advances in diagnosis and treatment of children with intellectual disabilities since the publication of the original AAP clinical report in 2006 1 and provides current guidance for the medical genetics evaluation. One intention is to inform primary care providers in the setting of the medical home so that they and families are knowledgeable about the purpose and process of the genetics evaluation. This report will emphasize advances in genetic diagnosis while updating information regarding the appropriate evaluation for inborn errors of metabolism and the role of imaging in this context. The reader is referred to the 2006 clinical report for background information that remains relevant, including the roles of the medical home or pediatric primary care provider.

This clinical report will not address the importance of developmental screening in the medical home, nor will it address the diagnostic evaluation of the child with an autism spectrum disorder who happens to have ID as a co-occurring disability. (For AAP guidance related to Autism Spectrum Disorders, see Johnson and Myers. 2 )

For both pediatric primary care providers and families, there are specific benefits to establishing an etiologic diagnosis ( Table 1 ): clarification of etiology; provision of prognosis or expected clinical course; discussion of genetic mechanism(s) and recurrence risks; refined treatment options; the avoidance of unnecessary and redundant diagnostic tests; information regarding treatment, symptom management, or surveillance for known complications; provision of condition-specific family support; access to research treatment protocols; and the opportunity for comanagement of patients, as appropriate, in the context of a medical home to ensure the best health, social, and health care services satisfaction outcomes for the child and family. The presence of an accurate etiologic diagnosis along with a knowledgeable, experienced, expert clinician is one factor in improving the psychosocial outcomes for children and with intellectual disabilities and their families. 3 , – 5 Although perhaps difficult to measure, this “healing touch” contributes to the general well-being of the family. “As physicians we have experience with other children who have the same disorder, access to management programs, knowledge of the prognosis, awareness of research on understanding the disease and many other elements that when shared with the parents will give them a feeling that some control is possible.” 5  

The Purposes of the Comprehensive Medical Genetics Evaluation of the Young Child With GDD or ID

Makela et al 6 studied, in depth, 20 families of children with ID with and without an etiologic diagnosis and found that these families had specific stated needs and feelings about what a genetic diagnosis offers:

Validation: a diagnosis established that the problem (ID) was credible, which empowered them to advocate for their child.

Information: a diagnosis was felt to help guide expectations and management immediately and provide hope for treatment or cure in future.

Procuring services: the diagnosis assisted families in obtaining desired services, particularly in schools.

Support: families expressed the need for emotional companionship that a specific diagnosis (or “similar challenges”) assisted in accessing.

Need to know: families widely differed in their “need to know” a specific diagnosis, ranging from strong to indifferent.

Prenatal testing: families varied in their emotions, thoughts, and actions regarding prenatal genetic diagnosis.

For some families in the Makela et al 6 study, the clinical diagnosis of autism, for example, was sufficient and often more useful than “a rare but specific etiological diagnosis.” These authors report that “all of the families would have preferred to have an [etiologic] diagnosis, if given the option,” particularly early in the course of the symptoms.

As was true of the 2006 clinical report, this clinical report will not address the etiologic evaluation of young children who are diagnosed with cerebral palsy, autism, or a single-domain developmental delay (gross motor delay or specific language impairment). 1 Some children will present both with GDD and clinical features of autism. In such cases, the judgment of the clinical geneticist will be important in determining the evaluation of the child depending on the primary neurodevelopmental diagnosis. It is recognized that the determination that an infant or young child has a cognitive disability can be a matter of clinical judgment, and it is important for the pediatrician and consulting clinical geneticist to discuss this before deciding on the best approach to the diagnostic evaluation.” 1  

ID is a developmental disability presenting in infancy or the early childhood years, although in some cases, it cannot be diagnosed until the child is older than ∼5 years of age, when standardized measures of developmental skills become more reliable and valid. The American Association on Intellectual and Developmental Disability defines ID by using measures of 3 domains: intelligence (IQ), adaptive behavior, and systems of supports afforded the individual. 7 Thus, one cannot rely solely on the measure of IQ to define ID. More recently, the term ID has been suggested to replace “mental retardation.” 7 , 8 For the purposes of this clinical report, the American Association on Intellectual and Developmental Disability definition is used: “Intellectual disability is a disability characterized by significant limitations both in intellectual functioning and in adaptive behavior as expressed in conceptual, social and practical adaptive skills. The disability originates before age 18 years.” 7 The prevalence of ID is estimated to be between 1% and 3%. Lifetime costs (direct and indirect) to support individuals with ID are large, estimated to be an average of approximately $1 million per person. 9  

Identifying the type of developmental delay is an important preliminary step, because typing influences the path of investigation later undertaken. GDD is defined as a significant delay in 2 or more developmental domains, including gross or fine motor, speech/language, cognitive, social/personal, and activities of daily living and is thought to predict a future diagnosis of ID. 10 Such delays require accurate documentation by using norm-referenced and age-appropriate standardized measures of development administered by experienced developmental specialists. The term GDD is reserved for younger children (ie, typically younger than 5 years), whereas the term ID is usually applied to older children for whom IQ testing is valid and reliable. Children with GDD are those who present with delays in the attainment of developmental milestones at the expected age; this implies deficits in learning and adaptation, which suggests that the delays are significant and predict later ID. However, delays in development, especially those that are mild, may be transient and lack predictive reliability for ID or other developmental disabilities. For the purposes of this report, children with delays in a single developmental domain (for example, isolated mild speech delay) should not be considered appropriate candidates for the comprehensive genetic evaluation process set forth here. The prevalence of GDD is estimated to be 1% to 3%, similar to that of ID.

Schaefer and Bodensteiner 11 wrote that a specific diagnosis is that which “can be translated into useful clinical information for the family, including providing information about prognosis, recurrence risks, and preferred modes of available therapy.” For example, agenesis of the corpus callosum is considered a sign and not a diagnosis, whereas the autosomal-recessive Acrocallosal syndrome (agenesis of the corpus callosum and polydactyly) is a clinical diagnosis. Van Karnebeek et al 12 defined etiologic diagnosis as “sufficient literature evidence…to make a causal relationship of the disorder with mental retardation likely, and if it met the Schaefer-Bodensteiner definition.” This clinical report will use this Van Karnebeek modification of the Schaefer–Bodensteiner definition and, thus, includes the etiology (genetic mutation or genomic abnormality) as an essential element to the definition of a diagnosis.

Recommendations are best when established from considerable empirical evidence on the quality, yield, and usefulness of the various diagnostic investigations appropriate to the clinical situation. The evidence for this clinical report is largely based on many small- or medium-size case series and on expert opinion. The report is based on a review of the literature by the authors.

Significant changes in genetic diagnosis in the last several years have made the 2006 clinical report out-of-date. First, the chromosome microarray (CMA) is now considered a first-line clinical diagnostic test for children who present with GDD/ID of unknown cause. Second, this report highlights a renewed emphasis on the identification of “treatable” causes of GDD/ID with the recommendation to consider screening for inborn errors of metabolism in all patients with unknown etiology for GDD/ID. 13  

Nevertheless, the approach to the patient remains familiar to pediatric primary care providers and includes the child’s medical history (including prenatal and birth histories); the family history, which includes construction and analysis of a pedigree of 3 generations or more; the physical and neurologic examinations emphasizing the examination for minor anomalies (the “dysmorphology examination”); and the examination for neurologic or behavioral signs that might suggest a specific recognizable syndrome or diagnosis. After the clinical genetic evaluation, judicious use of laboratory tests, imaging, and other consultations on the basis of best evidence are important in establishing the diagnosis and for care planning.

CMA now should be considered a first-tier diagnostic test in all children with GDD/ID for whom the causal diagnosis is not known. G-banded karyotyping historically has been the standard first-tier test for detection of genetic imbalance in patients with GDD/ID for more than 35 years. CMA is now the standard for diagnosis of patients with GDD/ID, as well as other conditions, such as autism spectrum disorders or multiple congenital anomalies. 14 , – 24 The G-banded karyotype allows a cytogeneticist to visualize and analyze chromosomes for chromosomal rearrangements, including chromosomal gains (duplications) and losses (deletions). CMA performs a similar function, but at a much “higher resolution,” for genomic imbalances, thus increasing the sensitivity substantially. In their recent review of the CMA literature, Vissers et al 25 report the diagnostic rate of CMA to be at least twice that of the standard karyotype. CMA, as used in this clinical report, encompasses all current types of array-based genomic copy number analyses, including array-based comparative genomic hybridization and single-nucleotide polymorphism arrays (see Miller et al 15 for a review of array types). With these techniques, a patient’s genome is examined for detection of gains or losses of genome material, including those too small to be detectable by standard G-banded chromosome studies. 26 , 27 CMA replaces the standard karyotype (“chromosomes”) and fluorescent in situ hybridization (FISH) testing for patients presenting with GDD/ID of unknown cause. The standard karyotype and certain FISH tests remain important to diagnostic testing but now only in limited clinical situations (see Manning and Hudgins 14 ) in which a specific condition is suspected (eg, Down syndrome or Williams syndrome). The discussion of CMA does not include whole-genome sequencing, exome sequencing, or “next-generation” genome sequencing; these are discussed in the “emerging technologies” section of this report.

Twenty-eight case series have been published addressing the rate of diagnosis by CMA of patients presenting with GDD/ID. 28 The studies vary by subject criteria and type of microarray technique and reflect rapid changes in technology over recent years. Nevertheless, the diagnostic yield for all current CMA is estimated at 12% for patients with GDD/ID. 14 , – 29 CMA is the single most efficient diagnostic test, after the history and examination by a specialist in GDD/ID.

CMA techniques or “platforms” vary. Generally, CMA compares DNA content from 2 differentially labeled genomes: the patient and a control. In the early techniques, 2 genomes were cohybridized, typically onto a glass microscope slide on which cloned or synthesized control DNA fragments had been immobilized. Arrays have been built with a variety of DNA substrates that may include oligonucleotides, complementary DNAs, or bacterial artificial chromosomes. The arrays might be whole-genome arrays, which are designed to cover the entire genome, or targeted arrays, which target known pathologic loci, the telomeres, and pericentromeric regions. Some laboratories offer chromosome-specific arrays (eg, for nonsyndromic X-linked ID [XLID]). 30 The primary advantage of CMA over the standard karyotype or later FISH techniques is the ability of CMA to detect DNA copy changes simultaneously at multiple loci in a genome in one “experiment” or test. The copy number change (or copy number variant [CNV]) may include deletions, duplications, or amplifications at any locus, as long as that region is represented on the array. CMA, independent of whether it is “whole genome” or “targeted” and what type of DNA substrate (single-nucleotide polymorphisms, 31 oligonucleotides, complementary DNAs, or bacterial artificial chromosomes), 32 identifies deletions and/or duplications of chromosome material with a high degree of sensitivity in a more efficient manner than FISH techniques. Two main factors define the resolution of CMA: (1) the size of the nucleic acid targets; and (2) the density of coverage over the genome. The smaller the size of the nucleic acid targets and the more contiguous the targets on the native chromosome are, the higher the resolution is. As with the standard karyotype, one result of the CMA test can be “of uncertain significance,” (ie, expert interpretation is required, because some deletions or duplications may not be clearly pathogenic or benign). Miller et al 15 describe an effort to develop an international consortium of laboratories to address questions surrounding array-based testing interpretation. This International Standard Cytogenomic Array Consortium 15 ( www.iscaconsortium.org ) is investigating the feasibility of establishing a standardized, universal system of reporting and cataloging CMA results, both pathologic and benign, to provide the physician with the most accurate and up-to-date information.

It is important for the primary care pediatrician to work closely with the clinical geneticist and the diagnostic laboratory when interpreting CMA test results, particularly when “variants of unknown significance” are identified. In general, CNVs are assigned the following interpretations: (1) pathogenic (ie, abnormal, well-established syndromes, de novo variants, and large changes); (2) variants of unknown significance; and (3) likely benign. 15 These interpretations are not essentially different than those seen in the standard G-banded karyotype. It is important to note that not all commercial health plans in the United States include this testing as a covered benefit when ordered by the primary care pediatrician; others do not cover it even when ordered by the medical geneticist. Typically, the medical genetics team has knowledge and experience in matters of payment for testing.

The literature does not stratify the diagnostic rates of CMA by severity of disability. In addition, there is substantial literature supporting the multiple factors (eg, social, environmental, economic, genetic) that contribute to mild disability. 33 Consequently, it remains within the judgment of the medical geneticist as to whether it is warranted to test the patient with mild (and familial) ID for pathogenic CNVs. In their review, Vissers et al 25 reported on several recurrent deletion or duplication syndromes with mild disability and commented on the variable penetrance of the more common CNV conditions, such as 1q21.1 microdeletion, 1q21.1 microduplication, 3q29 microduplication, and 12q14 microdeletion. Some of these are also inherited. Consequently, among families with more than one member with disability, it remains challenging for the medical geneticist to know for which patient with GDD/ID CMA testing is not warranted.

Recent efforts to evaluate reporting of CNVs among clinical laboratories indicate variability of interpretation because of platform variability in sensitivity. 34 , 35 Thus, the interpretation of CMA test abnormal results and variants of unknown significance, and the subsequent counseling of families should be performed in all cases by a medical geneticist and certified genetic counselor in collaboration with the reference laboratory and platform used. Test variability is resolving as a result of international collaborations. 36 With large data sets, the functional impact (or lack thereof) of very rare CNVs is better understood. Still, there will continue to be rare or unique CNVs for which interpretation remain ambiguous. The medical geneticist is best equipped to interpret such information to families and the medical home.

Since the 2006 AAP clinical report, several additional reports have been published regarding metabolic testing for a cause of ID. 13 , 37 , – 40 The percentage of patients with identifiable metabolic disorders as cause of the ID ranges from 1% to 5% in these reports, a range similar to those studies included in the 2006 clinical report. Likewise, these newer published case series varied by site, age range of patients, time frame, study protocol, and results. However, they do bring renewed focus to treatable metabolic disorders. 13 Furthermore, some of the disorders identified are not included currently in any newborn screening blood spot panels. Although the prevalence of inherited metabolic conditions is relatively low (0% to 5% in these studies), the potential for improved outcomes after diagnosis and treatment is high. 41  

In 2005, Van Karnebeek et al 40 reported on a comprehensive genetic diagnostic evaluation of 281 consecutive patients referred to an academic center in the Netherlands. All patients were subjected to a protocol for evaluation and studies were performed for all patients with an initially unrecognized cause of mental retardation and included urinary screen for amino acids, organic acids, oligosaccharides, acid mucopolysaccharides, and uric acid; plasma concentrations of total cholesterol and diene sterols of 7- and 8-dehydrocholesterol to identify defects in the distal cholesterol pathway; and a serum test to screen for congenital disorders of glycosylation (test names such as “carbohydrate-deficient transferrin”). In individual patients, other searches were performed as deemed necessary depending on results of earlier studies. This approach identified 7 (4.6%) subjects with “certain or probable” metabolic disorders among those who completed the metabolic screening ( n = 216). None of the 176 screening tests for plasma amino acids and urine organic acids was abnormal. Four children (1.4%) with congenital disorders of glycosylation were identified by serum sialotransferrins, 2 children had abnormal serum cholesterol and 7-dehydrocholesterol concentrations suggestive of Smith-Lemli-Opitz syndrome, 2 had evidence of a mitochondrial disorder, 1 had evidence of a peroxisomal disorder, and 1 had abnormal cerebrospinal fluid biogenic amine concentrations. These authors concluded that “screening for glycosylation defects proved useful, whereas the yield of organic acid and amino acid screening was negligible.”

In a similar study from the Netherlands done more recently, Engbers et al 39 reported on metabolic testing that was performed in 433 children whose GDD/ID remained unexplained after genetic/metabolic testing, which included a standard karyotype; urine screen for amino acids, organic acids, mucopolysaccharides, oligosaccharides, uric acid, sialic acid, purines, and pyrimidines; and plasma for amino acids, acylcarnitines, and sialotransferrins. Screenings were repeated, and additional testing, including cerebrospinal fluid studies, was guided by clinical suspicion. Metabolic disorders were identified and confirmed in 12 of these patients (2.7%), including 3 with mitochondrial disorders; 2 with creatine transporter disorders; 2 with short-chain acyl-coenzyme A dehydrogenase deficiency; and 1 each with Sanfilippo IIIa, a peroxisomal disorder; a congenital disorder of glycosylation; 5-methyltetrahydrofolate reductase deficiency; and deficiency of the GLUT1 glucose transporter.

Other studies have focused on the prevalence of disorders of creatine synthesis and transport. Lion-François et al 37 reported on 188 children referred over a period of 18 months with “unexplained mild to severe mental retardation, normal karyotype, and absence of fragile X syndrome” who were prospectively screened for congenital creatine deficiency syndromes. Children were from diverse ethnic backgrounds. Children with “polymalformative syndromes” were excluded. There were 114 boys (61%) and 74 girls (39%) studied. Creatine metabolism was evaluated by using creatine/creatinine and guanidinoacetate (GAA)-to-creatine ratios on a spot urine screen. Diagnosis was further confirmed by using brain proton magnetic resonance spectroscopy and mutation screening by DNA sequence analysis in either the SLC6A8 (creatine transporter defect) or the GAMT genes. This resulted in a diagnosis in 5 boys (2.7% of all; 4.4% of boys). No affected girls were identified among the 74 studied. All 5 boys also were late to walk, and 3 had “autistic features.” The authors concluded that all patients with undiagnosed ID have urine screened for creatine-to-creatinine ratio and GAA-to-creatine ratio. Similarly, Caldeira Arauja et al 38 studied 180 adults with ID institutionalized in Portugal, screening them for congenital creatine deficiency syndromes. Their protocol involved screening all subjects for urine and plasma uric acid and creatinine. Patients with an increased urinary uric acid-to-creatinine ratio and/or decreased creatinine were subjected to the analysis of GAA. GAMT activity was measured in lymphocytes and followed by GAMT gene analysis. This resulted in identifying 5 individuals (2.8%) from 2 families with GAMT deficiency. A larger but less selective study of 1600 unrelated male and female children with GDD/ID and/or autism found that 34 (2.1%) had abnormal urine creatine-to-creatinine ratios, although only 10 (0.6%) had abnormal repeat tests and only 3 (0.2%) were found to have an SLC6A8 mutation. 42 Clark et al 43 identified SLC6A8 mutations in 0.5% of 478 unrelated boys with unexplained GDD/ID.

Recently, van Karnebeek and Stockler reported 13 , 42 on a systematic literature review of metabolic disorders “presenting with intellectual disability as a major feature.” The authors identified 81 treatable genetic metabolic disorders presenting with ID as a major feature. Of these disorders, 50 conditions (62%) were identified by routinely available tests ( Tables 2 and 3 ). Therapeutic modalities with proven effect included diet, cofactor/vitamin supplements, substrate inhibition, enzyme replacement, and hematopoietic stem cell transplant. The effect on outcome (IQ, developmental performance, behavior, epilepsy, and neuroimaging) varied from improvement to halting or slowing neurocognitive regression. The authors emphasized the approach as one that potentially has significant impact on patient outcomes: “This approach revisits current paradigms for the diagnostic evaluation of ID. It implies treatability as the premise in the etiologic work-up and applies evidence-based medicine to rare diseases.” Van Karnebeek and Stockler 13 , 42 reported on 130 patients with ID who were “tested” per this metabolic protocol; of these, 6 (4.6%) had confirmed treatable inborn errors of metabolism and another 5 (3.8%) had “probable” treatable inborn error of metabolism.

Metabolic Screening Tests

See Fig 1 .

Serum lead, thyroid function studies not included as “metabolic tests” and to be ordered per clinician judgment.

Metabolic Conditions Identified by Tests Listed

Adapted from van Karnebeek and Stockler. 41  

Acylcarn, acylcarnitine profile; CPS, carbamyl phosphate synthetase; GA, glutaric acidemia; HHH, hyperornithinemia-hyperammonemia-homocitrullinuria; HMG-CoA, 3-hydroxy-3-methylglutaryl-coenzyme A; MHBD, 2-methyl-3-hydroxybutyryl CoA dehydrogenase; MMA, methylmalonic acidemia; MTHFR, methylenetetrahydrofolate reductase; NAGS, N-acetylglutamate synthase; OTC, ornithine transcarbamylase; PAA, plasma amino acids; PDH, pyruvate dehydrogenase; P-HCY, plasma homocysteine; PKU; phenylketonuria; PPA, propionic acid; SCOT, succinyl-CoA:3-ketoacid CoA transferase; SSADH, succinic semialdehyde dehydrogenase; UGAA/creat; urine guanidino acid/creatine metabolites; UMPS, urine mucopolysaccharides qualitative screen (glycosaminoglycans); UOA, urine organic acids; UOGS, urine oligosaccharides; UPP, urine purines and pyrimidines.

Late-onset form of condition listed; some conditions are identified by more than 1 metabolic test.

This literature supports the need to consider screening children presenting with GDD/ID for treatable metabolic conditions. Many metabolic screening tests are readily available to the medical home and/or local hospital laboratory service. Furthermore, the costs for these metabolic screening tests are relatively low.

For patients in whom a diagnosis is suspected, diagnostic molecular genetic testing is required to confirm the diagnosis so that proper health care is implemented and so that reliable genetic counseling can be provided. For patients with a clinical diagnosis of a Mendelian disorder that is certain, molecular genetic diagnostic testing usually is not required to establish the diagnosis but may be useful for health care planning. However, for carrier testing or for genetic counseling of family members, it is often essential to know the specific gene mutation in the proband.

For patients with GDD/ID for whom the diagnosis is not known, molecular genetic diagnostic testing is necessary, under certain circumstances, which is discussed in the next section.

There is an approximate 40% excess of boys in all studies of prevalence and incidence of ID. 44 , 45 Part of this distortion of the gender ratio is attributable to X-linked genetic disorders. 46 Consequently, genetic testing for X-linked genes in boys with GDD/ID is often warranted, particularly in patients whose pedigree is suggestive of an X-linked condition. In addition, for several reasons, research in X-linked genes that cause ID is advanced over autosomal genes, 46 , 47 thus accelerating the clinical capacity to diagnose XLID over autosomal forms.

Most common of these is fragile X syndrome, although the prevalence of all other X-linked genes involved in ID far exceeds that of fragile X syndrome alone. 46 Fragile X testing should be performed in all boys and girls with GDD/ID of unknown cause. Of boys with GDD/ID of uncertain cause, 2% to 3% will have fragile X syndrome (full mutation of FMR1 , >200 CGG repeats), as will 1% to 2% of girls (full mutation). 48  

Stevenson and Schwartz 49 suggest 2 clinical categories for those with XLID: syndromal and nonsyndromal. Syndromal refers to patients in whom physical or neurologic signs suggest a specific diagnosis; nonsyndromal refers to those with no signs or symptoms to guide the diagnostic process. Using this classification has practical applicability, because the pediatric primary care provider can establish a specific XLID syndrome on the basis of clinical findings. In contrast, nonsyndromal conditions can only be distinguished on the basis of the knowledge of their causative gene. 50 In excess of 215 XLID conditions have been recorded, and >90 XLID genes have been identified. 46 , 50  

To address male patients with GDD/ID and X-linked inheritance, there are molecular genetic diagnostic “panels” of X-linked genes available clinically. These panels examine many genes in 1 “test sample.” The problem for the clinical evaluation is in which patient to use which test panel, because there is no literature on head-to-head performance of test panels, and the test panels differ somewhat by genes included, test methods used, and the rate of a true pathogenic genetic diagnosis. Nevertheless, the imperative for the diagnostic evaluation remains the same for families and physicians, and there is a place for such testing in the clinical evaluation of children with GDD/ID. For patients with an X-linked pedigree, genetic testing using one of the panels is clinically indicated. The clinical geneticist is best suited to guide this genetic testing of patients with possible XLID. For patients with “syndromal” XLID (eg, Coffin-Lowry syndrome), a single gene test rather than a gene panel is indicated. Whereas those patients with “nonsyndromal” presentation might best be assessed by using a multigene panel comprising many of the more common nonsyndromal XLID genes. The expected rate of the diagnosis may be high. Stevenson and Schwartz 46 reported, for example, on 113 cases of nonspecific ID testing using a 9-gene panel of whom 9 (14.2%) had pathogenic mutations identified. de Brouwer et al 51 reported on 600 families with multiple boys with GDD/ID and normal karyotype and FMR1 testing. Among those families with “an obligate female carrier” (defined by pedigree analysis and linkage studies), a specific gene mutation was identified in 42%. In addition, in those families with more than 2 boys with ID and no obligate female carrier or without linkage to the X chromosome, 17% of the ID cases could be explained by X-linked gene mutations. This very large study suggested that testing of individual boys for X-linked gene mutations is warranted.

Recently, clinical laboratories have begun offering “high-density” X-CMAs to assess for pathogenic CNVs (see previous discussion regarding microarrays) specifically for patients with XLID. Wibley et al 30 (2010) reported on CNVs in 251 families with evidence of XLID who were investigated by array comparative genomic hybridization on a high-density oligonucleotide X-chromosome array platform. They identified pathogenic CNVs in 10% of families. The high-density arrays for XLID are appropriate in those patients with syndromal or nonsyndromal XLID. The expected diagnostic rate remains uncertain, although many pathogenic segmental duplications are reported (for a catalog of X-linked mutations and CNVs, see http://www.ggc.org/research/molecular-studies/xlid.html ).

Whole exome sequencing and whole-genome sequencing are emerging testing technologies for patients with nonspecific XLID. Recently, Tarpey et al 52 have reported the results of the large-scale systematic resequencing of the coding X chromosome to identify novel genes underlying XLID. Gene coding sequences of 718 X-chromosome genes were screened via Sanger sequencing technology in probands from 208 families with probable XLID. This resequencing screen contributed to the identification of 9 novel XLID-associated genes but identified pathogenic sequence variants in only 35 of 208 (17%) of the cohort families. This figure likely underestimates the general contribution of sequence variants to XLID given the subjects were selected from a pool that had had previous clinical and molecular genetic screening. 30  

Table 4 lists some common XLID conditions. In cases in which the diagnosis is not certain, molecular genetic testing of patients for the specific gene is indicated, even if the pedigree does not indicate other affected boys (ie, cannot confirm X-linked inheritance). 46  

Common Recognizable XLID Syndromes

Reproduced with permission from Stevenson and Schwartz. 46  

Rett syndrome is an X-linked condition that affects girls and results from MECP2 gene mutations primarily (at least 1 other gene has been determined causal in some patients with typical and atypical Rett syndrome: CDKL5) . Girls with mutations in the MECP2 gene do not always present clinically with classic Rett syndrome. Several large case series have examined the rate of pathogenic MECP2 mutations in girls and boys with ID. The proportion of MECP2 mutations in these series ranged from 0% to 4.4% with the average of 1.5% among girls with moderate to severe ID. 53 , – 62   MECP2 mutations in boys present with severe neonatal encephalopathy and not with GDD/ID.

Currently, the literature does not indicate consensus on the role that neuroimaging, either by computed tomography (CT) or MRI, can play in the evaluation of children with GDD/ID. Current recommendations range from performing brain imaging on all patients with GDD/ID, 63 to performing it only on those with indications on clinical examination, 12 to being considered as a second-line investigation to be undertaken when features in addition to GDD are detected either on history or physical examination. The finding of a brain abnormality or anomaly on neuroimaging may lead to the recognition of a specific cause of an individual child’s developmental delay/ID in the same way that a dysmorphologic examination might lead to the inference of a particular clinical diagnosis. However, like other major or minor anomalies noted on physical examination, abnormalities on neuroimaging typically are not sufficient for determining the cause of the developmental delay/ID; the underlying precise, and presumably frequently genetic in origin, cause of the brain anomaly is often left unknown. Thus, although a central nervous system (CNS) anomaly (often also called a “CNS dysgenesis”) is a useful finding and indeed may be considered, according to the definition of Schaefer and Bodensteiner, 11 a useful “diagnosis.” However, it is frequently not an etiologic or syndromic diagnosis. This distinction is not always made in the literature on the utility of neuroimaging in the evaluation of children with developmental delay/ID. The lack of a consistent use of this distinction has led to confusion regarding this particular issue.

Early studies on the use of CT in the evaluation of children with idiopathic ID 64 indicated a low diagnostic yield for the nonspecific finding of “cerebral atrophy,” which did not contribute to clarifying the precise cause of the ID. 65 Later studies that used MRI to detect CNS abnormalities suggested that MRI was more sensitive than CT, with an increased diagnostic yield. 10 , 66 The rate of abnormalities actually detected on imaging varies widely in the literature as a result of many factors, such as subject selection and the method of imaging used (ie, CT or MRI). Schaefer and Bodensteiner, 63 in their literature review, found reported ranges of abnormalities from 9% to 80% of those patients studied. Shevell et al 10 reported a similar range of finding in their review. For example, in 3 studies totaling 329 children with developmental delay in which CT was used in almost all patients and MRI was used in but a small sample, a specific cause was determined in 31.4%, 67 27%, 68 and 30% 69 of the children. In their systematic review of the literature, van Karnebeek et al 12 reported on 9 studies that used MRI in children with ID. The mean rate of abnormalities found was 30%, with a range of 6.2% to 48.7%. These investigators noted that more abnormalities were found in children with moderate to profound ID versus those with borderline to mild ID (mean yield of 30% and 21.2%, respectively). These authors also noted that none of the studies reported on the value of the absence of any neurologic abnormality for a diagnostic workup and concluded that “the value for finding abnormalities or the absence of abnormalities must be higher” than the 30% mean rate implied.

If neuroimaging is performed in only selected cases, such as children with an abnormal head circumference or an abnormal focal neurologic finding, the rate of abnormalities detected is increased further than when used on a screening basis in children with a normal neurologic examination except for the documentation of developmental delay. Shevell et al 68 reported that the percentage of abnormalities were 13.9% if neuroimaging was performed on a “screening basis” but increased to 41.2% if performed on “an indicated basis.” Griffiths et al 70 highlighted that the overall risk of having a specific structural abnormality found on MRI scanning was 28% if neurologic symptoms and signs other than developmental delay were present, but if the developmental delay was isolated, the yield was reduced to 7.5%. In a series of 109 children, Verbruggen et al 71 reported an etiologic yield on MRI of 9%. They noted that all of these children had neurologic signs or an abnormal head circumference. In their practice parameter, the American Academy of Neurology and the Child Neurology Society 10 discussed other studies on smaller numbers of patients who showed similar results, which led to their recommendation that “neuroimaging is a recommended part of the diagnostic evaluation,” particularly should there be abnormal findings on examination (ie, microcephaly, macrocephaly, focal motor findings, pyramidal signs, extrapyramidal signs) and that MRI is preferable to CT. However, the authors of the American College of Medical Genetics Consensus Conference Report 10 stated that neuroimaging by CT or MRI in normocephalic patients without focal neurologic signs should not be considered a “standard of practice” or mandatory and believed that decisions regarding “cranial imaging will need to follow (not precede) a thorough assessment of the patient and the clinical presentation.” In contrast, van Karnebeek et al 12 found that MRI alone leads to an etiologic diagnosis in a much lower percentage of patients studied. They cited Kjos et al, 72 who reported diagnoses in 3.9% of patients who had no known cause for their ID and who did not manifest either a progressive or degenerative course in terms of their neurologic symptomatology. Bouhadiba et al 73 reported diagnoses in 0.9% of patients with neurologic symptoms, and in 4 additional studies, no etiologic or syndromic diagnosis on the basis of neuroimaging alone was found. 65 , 69 , 74 , 75 The authors of 3 studies reported the results on unselected patients; Majnemer and Shevell 67 reported a diagnosis by this typed unselected investigation in 0.2%, Stromme 76 reported a diagnosis in 1.4% of patients, and van Karnebeek et al 40 reported a diagnosis in 2.2% of patients.

Although a considerable evolution has occurred over the past 2 decades in neuroimaging techniques and modalities, for the most part with the exception of proton magnetic resonance spectroscopy, this has not been applied or reported in the clinical situation of developmental delay/ID in childhood. Proton resonance spectroscopy provides a noninvasive mechanism of measuring brain metabolites, such as lactate, using technical modifications to MRI. Martin et al 77 did not detect any differences in brain metabolite concentrations among stratifications of GDD/ID into mild, moderate, and severe levels. Furthermore, they did not detect any significant differences in brain metabolite concentration between children with GDD/ID and age-matched typically developing control children. Thus, these authors concluded that proton resonance spectroscopy “has little information concerning cause of unexplained DD.” Similarly, the studies by Martin et al 77 and Verbruggen et al 71 did not reveal that proton magnetic resonance spectroscopy was particularly useful in the determination of an underlying etiologic diagnosis in children with unexplained developmental delay/ID.

All of these findings suggest that abnormal findings on MRI are seen in ∼30% of children with developmental delay/ID. However, only in a fraction of these children does MRI lead to an etiologic or syndromic diagnosis. The precise value of a negative MRI result in leading to a diagnosis has not yet been studied in detail. In addition, MRI in the young child with developmental delay/ID invariably requires sedation or, in some cases, anesthesia to immobilize the child to accomplish the imaging study. This need, however, is decreasing with faster acquisition times provided by more modern imaging technology. Although the risk of sedation or anesthesia is small, it still merits consideration within the decision calculus for practitioners and the child’s family. 63 , 78 , 79 Thus, although MRI is often useful in the evaluation of the child with developmental delay/ID, at present, it cannot be definitively recommended as a mandatory study, and it certainly has higher diagnostic yields when concurrent neurologic indications exist derived from a careful physical examination of the child (ie, microcephaly, microcephaly, seizures, or focal motor findings).

The following is the recommended medical genetic diagnostic evaluation flow process for a new patient with GDD/ID. All patients with ID, irrespective of degree of disability, merit a comprehensive medical evaluation coordinated by the medical home in conjunction with the medical genetics specialist. What follows is the clinical genetics evaluation ( Fig 1 ):

Diagnostic process and care planning. Metabolic test 1: blood homocysteine, acylcarnitine profile, amino acids; and, urine organic acids, glycosaminoglycans, oligosaccharides, purines, pyrimidines, GAA/creatine metabolites. Metabolic test 2 based on clinical signs and symptoms. FH, family history; MH, medical history; NE, neurologic examination; PE, physical and dysmorphology examination.

Complete medical history; 3-generation family history; and physical, dysmorphologic, and neurologic examinations.

If the specific diagnosis is certain, inform the family and the medical home, providing informational resources for both; set in place an explicit shared health care plan 80 with the medical home and family, including role definitions; provide sources of information and support to the family; provide genetic counseling services by a certified genetic counselor; and discuss treatment and prognosis. Confirm the clinical diagnosis with the appropriate genetic testing, as warranted by clinical circumstances.

If a specific diagnosis is suspected, arrange for the appropriate diagnostic studies to confirm including single-gene tests or chromosomal microarray test.

If diagnosis is unknown and no clinical diagnosis is strongly suspected, begin the stepwise evaluation process:

Chromosomal microarray should be performed in all.

Specific metabolic testing should be considered and should include serum total homocysteine, acyl-carnitine profile, amino acids; and urine organic acids, glycosaminoglycans, oligosaccharides, purines, pyrimidines, GAA/creatine metabolites.

Fragile X genetic testing should be performed in all.

If no diagnosis is established:

Male gender and family history suggestive X-linkage, complete XLID panel that contains genes causal of nonsyndromic XLID and complete high-density X-CMA. Consider X-inactivation skewing in the mother of the proband.

Female gender: complete MECP2 deletion, duplication, and sequencing study.

If microcephaly, macrocephaly, or abnormal findings on neurologic examination (focal motor findings, pyramidal signs, extrapyramidal signs, intractable epilepsy, or focal seizures), perform brain MRI.

If brain MRI findings are negative or normal, review status of diagnostic evaluation with family and medical home.

Consider referrals to other specialists, signs of inborn errors of metabolism for which screening has not yet been performed, etc.

If no further studies appear warranted, develop a plan with the family and medical home for needed services for child and family; also develop a plan for diagnostic reevaluation.

Health care systems, processes, and outcomes vary geographically, and not all of what is recommended in this clinical report is easily accessible in all regions of the United States. 21 , 81 , – 84 Consequently, local factors affect the process of evaluation and care. These arrangements are largely by local custom or design. In some areas, there may be quick access and intimate coordination between the medical home and medical genetics specialist, but in other regions, access may be constrained by distance or by decreased capacity, making for long wait times for appointments. Some general pediatricians have the ability to interpret the results of genetic testing that they may order. In addition, children with GDD or ID are often referred by pediatricians to developmental pediatricians, child neurologists, or other subspecialists. It is appropriate for some elements of the medical genetic evaluation to be performed by physicians other than medical geneticists if they have the ability to interpret the test results and provide appropriate counseling to the families. In such circumstances, the diagnostic evaluation process can be designed to address local particularities. The medical home is responsible for referrals of the family and child to the appropriate special education or early developmental services professional for individualized services. In addition, the medical home can begin the process of the diagnostic evaluation if access is a problem and in coordination with colleagues in medical genetics. 80 , 85 What follows is a suggested process for the evaluation by the medical home and the medical genetics specialist and only applies where access is a problem; any such process is better established with local particularities in mind:

Medical home completes the medical evaluation, determines that GDD/ID is present, counsels family, refers to educational services, completes a 3-generation family history, and completes the physical examination and addresses the following questions:

Does the child have abnormalities on the dysmorphologic examination?

If no or uncertain, obtain microarray, perform fragile X testing, and consider the metabolic testing listed previously. Confirm that newborn screening was completed and reported negative. Refer to medical genetics while testing is pending.

If yes, send case summary and clinical photo to medical genetics center for review for syndrome identification. If diagnosis is suspected, arrange for expedited medical genetics referral and hold all testing listed above. Medical geneticist to arrange visit with genetic counselor for testing for suspected condition.

Does the child have microcephaly, macrocephaly, or abnormal neurologic examination (listed above)? If “yes,” measure parental head circumferences and review the family history for affected and unaffected members. If normal head circumferences in both parents and negative family history, obtain brain MRI and refer to medical genetics.

Does child also have features of autism, cerebral palsy, epilepsy, or sensory disorders (deafness, blindness)? This protocol does not address these patients; manage and refer as per local circumstances.

As above are arranged and completed and negative, refer to medical genetics and hold on additional diagnostic testing until consultation completed. Continue with current medical home family support services and health care.

Should a diagnosis be established, the medical home, medical geneticist, and family might then agree to a care plan with explicit roles and responsibilities of all.

Should a diagnosis not be established by medical genetics consultation, the medical home, family, and medical geneticist can then agree on the frequency and timing of diagnostic reevaluation while providing the family and child services needed.

Several research reports have cited whole-exome sequencing and whole-genome sequencing in patients with known clinical syndromes for whom the causative gene was unknown. These research reports identified the causative genes in patients with rare syndromes (eg, Miller syndrome, 86 Charcot-Marie-Tooth disease, 87 and a child with severe inflammatory bowel disease 88 ). Applying similar whole-genome sequencing of a family of 4 with 1 affected individual, Roach et al 86 identified the genes for Miller syndrome and primary ciliary dyskinesia. The ability to do whole-genome sequencing and interpretation at an acceptable price is on the horizon. 87 , 89 The use of exome or whole-genome sequencing challenges the field of medical genetics in ways not yet fully understood. When a child presents with ID and whole-genome sequencing is applied, one will identify mutations that are unrelated to the question being addressed, in this case “What is the cause of the child’s intellectual disability?” One assumes that this will include mutations that families do not want to have (eg, adult-onset disorders for which no treatment now exists). This is a sea change for the field of medical genetics, and the implications of this new technology have not been fully explored. In addition, ethical issues regarding validity of new tests, uncertainty, and use of resources will need to be addressed as these technologies become available for clinical use. 90 , 91  

The medical genetic diagnostic evaluation of the child with GDD/ID is best accomplished in collaboration with the medical home and family by using this clinical report to guide the process. The manner in which the elements of this clinical protocol are applied is subject to local circumstances, as well as the decision-making by the involved pediatric primary care provider and family. The goals and the process of the diagnostic evaluation are unchanged: to improve the health and well-being of those with GDD/ID. It is important to emphasize the new role of the genomic microarray as a first-line test, as well as the renewal of efforts to identify the child with an inborn error of metabolism. The future use of whole-genome sequencing offers promise and challenges needing to be addressed before regular implementation in the clinic.

John B. Moeschler, MD, MS, FAAP, FACMG

Michael Shevell, MDCM, FRCP

Robert A. Saul, MD, FAAP, Chairperson

Emily Chen, MD, PhD, FAAP

Debra L. Freedenberg, MD, FAAP

Rizwan Hamid, MD, FAAP

Marilyn C. Jones, MD, FAAP

Joan M. Stoler, MD, FAAP

Beth Anne Tarini, MD, MS, FAAP

Stephen R. Braddock, MD

Katrina M. Dipple, MD, PhD – American College of Medical Genetics

Melissa A. Parisi, MD, PhD – Eunice Kennedy Shriver National Institute of Child Health and Human Development

Nancy Rose, MD – American College of Obstetricians and Gynecologists

Joan A. Scott, MS, CGC – Health Resources and Services Administration, Maternal and Child Health Bureau

Stuart K. Shapira, MD, PhD – Centers for Disease Control and Prevention

American Academy of Pediatrics

chromosome microarray

central nervous system

copy number variant

computed tomography

fluorescent in situ hybridization

guanidinoacetate

global developmental delay

intellectual disability

X-linked intellectual disability

This document is copyrighted and is property of the American Academy of Pediatrics and its Board of Directors. All authors have filed conflict of interest statements with the American Academy of Pediatrics. Any conflicts have been resolved through a process approved by the Board of Directors. The American Academy of Pediatrics has neither solicited nor accepted any commercial involvement in the development of the content of this publication.

The guidance in this report does not indicate an exclusive course of treatment or serve as a standard of medical care. Variations, taking into account individual circumstances, may be appropriate.

All clinical reports from the American Academy of Pediatrics automatically expire 5 years after publication unless reaffirmed, revised, or retired at or before that time.

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• Published: 20 September 2023

Assessment of rehabilitation effects in children with mild intellectual disability

• Andżelina Wolan-Nieroda 1 ,
• Anna Wojnarska 2 ,
• Grzegorz Mańko 3 , 4 ,
• Aleksandra Kiper 5 ,
• Agnieszka Guzik 1 &
• Andrzej Maciejczak 6  

Scientific Reports volume  13 , Article number:  15541 ( 2023 ) Cite this article

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• Neurodevelopmental disorders
• Paediatrics

Research on effectiveness of rehabilitation programmes continues to investigate impact of therapeutic interventions on various motor parameters in children with intellectual disability (ID). This study compared the effectiveness of rehabilitation, reflected by physical fitness, static balance, and dynamic balance measurements, in children with mild ID. A total of 70 children with mild ID were enrolled for the study and were divided into two equal groups based on their body mass index (BMI) percentile, reflecting obesity or normal weight. Physical fitness was assessed using the Eurofit Special Test, whereas balance was evaluated with single-leg stance and timed up and go tests. The examinations were performed twice: At the beginning and at the end of a six-month therapy programme. Improvements were shown in the muscle strength of the upper limbs ( p  < 0.001) and lower limbs ( p  = 0.001), flexibility ( p  = 0.005), and static balance ( p  < 0.001) for the entire cohort. The effects of rehabilitation did not differ significantly between the children with obesity and those with a normal weight. These results may be important from the viewpoint of clinical practice and preventive measures, as they present evidence showing that rehabilitation is equally effective in both obese and normal weight children with mild ID. Therefore, these findings may be of assistance to those designing therapeutic programmes in special education centres.

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Tai chi-muscle power training for children with developmental coordination disorder: a randomized controlled trial

Introduction.

Intellectual disability (ID) is defined as a spectrum of disorders and abnormalities in the intellectual, physical, motor, emotional, and social domains 1 , 2 . The term "pure form" of intellectual disability refers to the case where the person affected is characterised solely by intellectual impairment, without accompanying additional developmental or medical disorders. In this situation, intellectual deficit is the only major factor impacting the person's functional status, whereas his/her physical capacities, health and other aspects do not present abnormalities. The current study focused on children with mild ID, classified as "pure form ID", in order to better understand the impact of rehabilitation on this specific group of children. Children affected by this condition experience a variety of challenges related to learning, communication, social skills and independent functioning 1 , 2 , 3 . Furthermore, existing reports suggest that children with ID are most likely to have problems with balance, coordination, endurance, flexibility, and muscle strength 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 . For many of them, appropriate rehabilitation may be an effective tool to enable improvement in the quality of life and functioning. Rehabilitation designed for children with ID mainly focuses on improving their motor skills, as well as self-care and social skills, in order to enable their social engagement and to foster their independence 6 , 7 , 8 , 9 .

Researchers focusing on effectiveness of rehabilitation programs continue to investigate impact of therapeutic interventions on various motor parameters in children with ID. Muscle strength, balance and dexterity play a key role in daily activities and self-care. Likewise, muscular endurance, speed, and flexibility are key elements impacting the ability to perform a variety of motor activities 4 , 5 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 . Furthermore, it may be important to understand in what way these motor parameters are affected by body mass index (BMI). Excessive body weight, particularly obesity, can affect muscle strength, flexibility and endurance, which can impact the overall effectiveness of therapeutic interventions 6 , 7 , 8 , 9 , 10 . A review of the related publications focusing on these issues showed that there are few studies investigating the gains from rehabilitation programmes intended for children with "pure form of ID 4 , 6 , 9 . Moreover, the relationship between BMI and effects of rehabilitation administered to children with ID has rarely been investigated. The only studies available assess the effect of BMI on the motor capacities exhibited by these children 6 , 7 , 8 , 9 , 12 .

Therefore, we envisage that our study will contribute evidence of key importance for understanding the comprehensive impact of rehabilitation on different aspects of functioning in children with ID, and may provide information which will help design therapies matching the specific needs of each child. With the results obtained, therapists and specialists will be able to create personalised therapy programmes that comprehensively support the motor development and quality of life in children with ID.

The present study aimed to assess the effects of rehabilitation programme on the static balance and dynamic balance in children with mild ID, and on their physical fitness reflected by such motor parameters as upper and lower limb muscle strength, speed, flexibility and muscular endurance. Additionally, the study was designed to investigate whether the effects of rehabilitation differ between children, depending on their BMI.

Research questions:

1. Does a six-month rehabilitation programme produce a change in the lower and upper limb muscle strength, speed, flexibility, and local muscular endurance in children with mild ID in both the obesity group (O Group) and normal weight group (NW Group)?

2. Does participation in a six-month rehabilitation programme affect static and dynamic balance in children with mild ID in both O and NW Groups?

3. Do the effects of rehabilitation differ between children with mild ID and obesity (O Group) and children with mild ID and normal weight (NW Group)?

Participants

This study was carried out in a special educational facility in the Podkarpackie Region in Poland. A total of 70 children with mild ID were enrolled for the study, and they were allocated to two equal-size groups relative to their BMI. O Group comprised 35 children with mild ID and obesity, including 17 boys and 18 girls, with a mean age of 12.9 ± 1.38 years. The age- and sex-matched NW Group consisted of 35 children with mild ID and normal weight. The characteristics of the two groups are shown in Table 1 .

All of the children recruited for the study met these inclusion criteria: (a) mild ID; (b) age between 11 and 15 years; (c) BMI percentile matching one of the two body mass categories: obesity > 95th percentile (O Group) or normal weight > 5th and < 85th percentile (NW Group); (d) attendance of a special educational facility; (e) no motor disability; (f) participation in a uniform rehabilitation programme; (g) a health status allowing for participation in the examinations.

The exclusion criteria were as follows: (a) moderate to severe ID, with cognitive deficits impairing their ability to understand and follow instructions; (b) age under 11 or over 15 years; (c) BMI classified as overweight (> 85 and < 95 percentile) or underweight (< 5 percentile); (d) lack of parents' and/or legal guardians' informed consent for their children’s participation; (e) coexisting conditions: autism, Down syndrome, cerebral palsy, muscular dystrophy, or neurological disorders such as epilepsy or brain damage; (f) comorbidities such as rheumatic, orthopaedic, oncological, or cardiac diseases.

The children were qualified for the study based on the diagnosis of mild intellectual disability issued by the Psychological and Pedagogical Counselling Centre, where they had been assessed by a qualified psychologist experienced in working with individuals with ID. During that assessment process, the children’s intellectual capacities were measured using Wechsler Test 20 . Wechsler Intelligence Scale is a highly recognised psychometric test commonly used to evaluate intelligence. It was designed by David Wechsler to measure various aspects of the cognitive function. There are a few versions of the tool, adequate for different age groups, e.g., Wechsler Intelligence Scale for Children (WISC) and Wechsler Adult Intelligence Scale (WAIS). They comprise subtests assessing a number of cognitive domains such as verbal capacities (e.g., vocabulary, comprehension) and non-verbal capacities (e.g., pattern recognition, spatial thinking) 20 .

The children’s BMI percentile values were determined using the calculator developed in the OLAF project 21 . Based on these values, the children were assigned to matching body mass categories, in line with the classification applicable to children and adolescents, as adopted by the Centers for Disease Control and Prevention (CDC) 22 . Children with obesity were assigned to O Group, and those with normal body weight were included in NW Group.

An assessment of physical fitness and balance in the children from both groups was performed twice: At the start of the rehabilitation programme (Exam 1) and at the end of the six-month therapy programme (Exam 2). The measurements were carried out in a gym with the necessary equipment, i.e., gymnastic bench, mattresses, medicine balls, two 150 cm-tall marker flags, chair, stopper, and measuring tape. During the tests, the children were wearing sports attire that did not restrict their movements. Before the testing, a 10 min all-round warm-up was carried out. The specific test trials were conducted according to instructions, in a defined order. Each trial was preceded by an introduction, explanation and demonstration.

The experimental protocol was approved by the Scientific Research Ethics Committee of the University of Warmia and Mazury in Olsztyn (approval no. 9/2018). All of the procedures were executed in full compliance with the principles set forth in the Declaration of Helsinki. Parents or legal guardians of all the children were informed about the purpose of the study and provided written consent for their inclusion in the study.

Rehabilitation programme

The children in O and NW Groups participated in the therapy conducted with the same intensity and for the same duration of time. Rehabilitation sessions (45 min in duration), were held three times a week over a period of six months. The sessions in both groups followed the same schedule (Table 2 ). The therapy focused on improving functional strength, local muscular endurance and flexibility, static and dynamic balance, motor coordination and body schema, as well as spatial orientation. The programme consisted of introductory warm-up exercises, as well as aerobic exercise on static equipment (treadmill or bicycle), exercise strengthening postural muscles, balance and coordination exercises, breathing exercises, and exercises to develop body schema (getting to know one's own body by touching, looking at one's reflection in a mirror, showing and naming body parts, imitating the movements of another person) and spatial orientation. In addition to the therapy, the children in O and NW Groups participated in the regular activities and classes scheduled in the school, i.e., speech therapy and music, as well as visual and related arts.

Outcome measures

The following research tools were used in the study: The Eurofit Special Test 23 , 24 , the single-leg stance test with eyes open and closed 25 , and the timed up and go (TUG) test 26 .

The Eurofit Special Test is designed to assess the physical fitness of individuals with ID. It is a well-tested and reliable tool, commonly used to evaluate the overall fitness of children with ID 23 , 24 . It consists of six trials which assess: (1) dynamic balance—walking on gymnastic bench in the upright position (score expressed in points), children, assessed subjectively, could receive between 1 and 6 points with a higher score reflecting a better result; (2) lower limb muscle strength – standing long jump (in cm), measurements were taken to the nearest 1 cm, and a higher score reflected greater lower limb muscle strength; (3) upper limb muscle strength—a 2 kg medicine ball forward push with one hand (cm), measurements were taken to the nearest 1 cm, a higher score reflected greater upper limb muscle strength; (4) speed—a 25 m run from high start (in seconds), the time was measured in seconds to the nearest 0.1 s, a lower score meant that the designated distance was covered faster; (5) flexibility—seated forward bend (in points), measurements were taken to the nearest 1 cm, a higher score recorded from the '0' position reflected greater flexibility; (6) local muscular endurance—bent knee sit-ups (score ex-pressed in number) in 30 s, more repetitions reflected a better score 23 , 24 .

The single-leg stance test assesses static balance, measuring how long an individual can stand on one leg without support, with eyes open, and then with eyes closed. During the test, the subject stands barefoot on one leg while simultaneously bending the other knee backwards 90°, maintaining the thigh in a vertical position parallel to the standing leg. Separate measurements are taken for the right and left leg. The longer the balance is maintained, the better the result (recorded in seconds) 25 .

The timed up and go test is used to assess dynamic balance and independent mobility. It measures the time needed by an individual to get up from a chair, walk 3 m, complete a 180° turn, and return to the chair. This test is a popular balance assessment tool, and is therefore often used in clinical practice 26 .

Sample size

A minimum sample size (Nmin) of 58 subjects was determined for the population studied using a sample size calculator (“PLUS module” from Statistica 13.3 software). Overall, O Group and NW Group included 70 children. Nmin for the present study was calculated using the following formula:

where NP is total number of the population from which the sample is drawn; α represents the level of confidence for the results; f denotes the fraction size; and e stands for the anticipated maximum error.

Data analysis

Statistical analyses were computed using Statistica 13.3 software from StatSoft. Parametric and non-parametric tests were applied. A given test was selected if its assumptions were met, for instance, the normality of distributions of the variables was assessed using the Shapiro–Wilk W test, and verified using Kolmogorov–Smirnov test. The changes in the results over time (before and after therapy) were assessed using Student’s t test for dependent variables, or alternatively with Wilcoxon’s signed-rank test. Differences in the effects of the therapy obtained in the two groups were assessed using Student's t test for independent variables or alternatively with the Mann–Whitney U-test. The therapy effect was defined as the value of the difference between the result obtained after the therapy relative to the result obtained before the therapy. The results of the parametric tests are presented as the descriptive statistics of the mean values and standard deviation, whereas the results of the non-parametric tests are presented as the descriptive statistics of median value, as well as of the first and third quartile. A value of p < 0.05 was assumed to reflect statistical significance.

Research question 1: assessment of physical fitness in the whole cohort

Analysis of the scores achieved in the Eurofit Special Test by children with MID for the entire cohort, before and after the rehabilitation programme, showed statistically significant differences in the following measures: lower limb muscle strength in the standing long jump, upper limb muscle strength in the 2 kg medicine ball forward push with one hand, and flexibility in the seated forward bend. The scores in the trial assessing lower limb muscle strength after the therapy improved by 6.7 on average, compared to the measurement taken before the start of the rehabilitation programme, and this difference was statistically significant at p  < 0.001. The improvement in the children’s upper limb muscle strength at the end of the therapy is shown by the scores, which, on average, increased by 5.9, and the difference between the variables was statistically significant at a level of p  < 0.001. In the measure of flexibility, the improvement observed at the end of rehabilitation is reflected by a mean increase in the score by 1 cm compared to the results identified before the therapy, and the result was statistically significant at a level of p  < 0.005. Detailed data are shown in Table 3 . On the contrary, the assessments performed using the Eurofit Special Test showed no statistically significant changes in the scores identified before and after therapy for dynamic balance ( p  = 0.535), speed in the 25 m run test ( p  = 0.153), or local muscular endurance ( p  = 0.156) (Table 3 ).

Research question 2: assessment of static and dynamic balance in the entire cohort

Analysis of the results achieved by the entire cohort in the single-leg stance test before and after therapy showed significant changes in the scores for the trials with eyes open. On average, the scores improved by 5.2 s in the trials on the right leg, and by 5.7 s in the trials on the left leg. The identified differences were statistically significant at a level of p  < 0.001. The results reflecting static balance were also improved in the trials with eyes closed. The mean score improved by 2.3 s for the right leg, and by 2.4 s for the left leg. These differences were statistically significant ( p  < 0.001). The assessment of dynamic balance with the timed up and go test, performed before and after the rehabilitation programme, showed no statistically significant differences between the variables ( p  = 0.345). Detailed data are shown in Table 4 .

Research question 3: differences in the scores before/after and in the effects of rehabilitation between O and NW groups

The subsequent statistical analyses were intended to identify the differences in the scores before and after the rehabilitation programme, and in the effects of rehabilitation between O and NW groups, as reflected by the measurements of physical fitness (scores in the Eurofit Special Test specific trials), static balance (scores in single-leg stance test), and dynamic balance (scores in the timed up and go test).

First, a comparison of the groups was performed before the intervention and the only significant difference ( p  < 0.05) was identified in dynamic balance (timed up and go test); more specifically NW group was found with better dynamic balance before rehabilitation compared to O group. Conversely, the measurement of physical fitness (scores in the Eurofit Special Test specific trials) and static balance (scores in single-leg stance test) showed that before the intervention there were no statistically significant differences between the scores of O Group and NW Group ( p  > 0.05). Detailed data are shown in Table 5 and 6 .

Similarly, the measurements carried out after the intervention showed significant differences ( p  < 0.05) only in dynamic balance (timed up and go test); the scores achieved by NW group reflected better dynamic balance after rehabilitation compared to O group. On the other hand, the scores in physical fitness (Eurofit Special Test specific trials) and static balance (single-leg stance test) showed no statistically significant differences between O Group and NW Group ( p  > 0.05) after the intervention. Detailed data are shown in Table 5 and 6 .

Finally, the analyses focusing on the effects of rehabilitation reflected by the children’s physical fitness assessed using the specific trials of the Eurofit Special Test, showed no statistically significant differences between the effects achieved by O Group and NW Group ( p  > 0.05) Detailed data are shown in Table 5 . Similarly, no statistically significant differences in the effects of rehabilitation ( p  > 0.05) were found between O Group and NW Group in the measures of static balance (single-leg stance test with eyes open/closed) or dynamic balance (timed up and go test)—Table 6 .

The present study was designed to assess effectiveness of a rehabilitation programme in a group of children with mild ID. It assessed various aspects, such as physical performance and balance, to gain better understanding of the impact of rehabilitation in the case of children with mild ID. Additionally, the assessment aimed to determine whether or not rehabilitation effects differ relative to the children's BMI. A review of the related publications focusing on these issues showed that there are few studies investigating the gains from rehabilitation programmes intended for children with a “pure form” of ID 4 , 5 , 11 , 12 , 13 , 14 , 15 , 16 , 18 , 19 . The current study additionally adopted the approach which took into account children with mild ID and normal weight or obesity. The authors believe that this is the added value of this study, compared to earlier reports focusing on this subject matter 6 , 7 , 8 , 9 .

Another difference between our study and other research reports lies in the fact that we designed and used a comprehensive therapy programme focusing on multiple aspects. This programme was based on clinical experience of work with children with ID presenting with both obesity and normal weight. The programme comprised aerobic and anaerobic exercise, along with elements of strength and balance practice, as well as relaxation exercise. This is a novelty in this field of research, since the vast majority of the studies reported earlier applied strictly targeted interventions (e.g., trampoline exercise 14 , hippotherapy 15 , jumping rope 16 , strength training 17 , or rhythmic gymnastics 18 ). In fact, the above observations provided the motivation for the present study, which we believe contributes evidence that is important for use in clinical practice and in designing therapy programmes for children with ID.

First, the current study investigated the possible changes in physical fitness of an entire cohort of children with mild ID participating in a six-month rehabilitation programme. The findings showed that the programme contributed to better muscle strength in the lower extremities and arms, as well as better flexibility. The study by Golubović et al. also assessed physical fitness in children with ID in comparison to normally developing peers. Functional arm strength was measured using a flexed-arm hang test, while lower limb strength was assessed using a long jump test. The latter measure was the same as that in the current study. Although the results within the groups were not statistically significant, follow-up trials assessing the long-term effects of exercise showed the most visible improvement in strength in the children with ID participating in a six-month programme 18 . Another study, carried out by Xu et al., assessed muscle strength in the lower and upper limbs using a standing long jump test and a dumbbell press test. In this case, children with ID participated in a four-month adapted rhythmic gymnastics programme, whereas the control group took part in conventional physical education classes. The researchers reported that the children in the study group were found with significantly improved muscle strength in both the upper and lower limbs, whereas the improvement in the control group, identified in the lower limb muscle strength, was less pronounced 5 . Kachouri et al. assessed lower limb strength using a dynamometer and found improvements in muscle strength in the group participating in the training 27 . Similarly, Giagazoglou et al. reported that a three-month exercise programme provided to children with ID produced an increase in lower limb muscle strength and improved flexibility, assessed with a sit and reach test 15 , as in the present study. The outcome measure of flexibility in children with ID was also positively affected by a three-month sports games programme, as reported by Pejčić et al. 28 , and by a three-month jumping rope training programme applied in the study by Chao-Chien et al. 16 .

In contrast, the present study identified no significant changes in two motor characteristics at the end of the rehabilitation programme, i.e., running speed and local muscular endurance. We assume that the lack of improvement in running speed could be explained by the fact that speed is a motor characteristic that can only be improved to a small degree, as it is highly dependent on a person’s innate disposition 28 . Furthermore, it has been reported that, in comparison to the general population, individuals with ID typically achieve a lower running speed or speed of limb movement 29 . In the present study, local muscular endurance was assessed with a sit-up test. The same approach was applied by Golubović et al., who, in fact, found an improvement in this measure in children with ID following an exercise programme, yet the differences between the baseline and final assessment were not statistically significant 11 . The results in our study could be linked to the elements of our rehabilitation programme. An improvement in muscular endurance was not a primary focus of the programme, which only contained elements of endurance exercise as an addition to balance, strength, and other exercise.

The current study also investigated the effect of the six-month rehabilitation programme on static and dynamic balance in the entire cohort of children with mild ID. Dynamic balance was assessed in two ways: during one of the Eurofit Special Test trials, which involved walking on a gymnastic bench in the upright position, and with the up and go test. No changes in this measure were identified by these two tools at the end of the programme. Static balance was assessed using the single-leg stance test with eyes open and closed, and the trials showed significant positive changes in the scores at the end of the therapy. Different findings were reported by Golubović et al., who assessed static balance using the Flamingo Balance Test in a study group participating in a six-month exercise programme and in two control groups comprising children with ID and healthy children, matched for age, sex, and skills, not included in the training programme. In this case, no statistically significant differences between the first and second measurement were observed within the specific groups 11 . A potential improvement in the dynamic balance of children with mild ID was assessed by Giagazoglou et al. 15 . Children in the study group participated in a three-month exercise programme, whereas the control group attended physical education classes twice a week, in line with the school schedule. In this case, the researchers reported a significant improvement in balance in the study group. The differences in the scores between the first and second measurements in the latter group were statistically significant 15 . On the contrary, Dehghani et al. investigated the effectiveness of balance training 30 . Static and dynamic balance were assessed using a subtest of the Bruininks–Oseretsky Test of Motor Proficiency. Children assigned to the study group took part in a 10-week balance training programme, whereas the control group continued to follow the regular school schedule. The results of this study revealed significant differences between the pre- and post-intervention values in the study group for both static and dynamic balance 31 . Results similar to ours were acquired by Kachouri et al., who investigated the effectiveness of a two-month strength and proprioceptive training programme in children with mild ID. The authors reported improvements in balance in the group of children participating in the therapy 27 . Importantly, the current study revealed considerable improvements, both in the childre’'s lower limb muscle strength and in static balance following the rehabilitation programme. We believe that this observation is consistent with the findings of another study that showed a correlation between balance and leg strength in children with mild ID 32 . In their study, Jeng et al. carried out a physical fitness follow-up in children with cerebral palsy undertaking a 12-week individualised exercise training regime. They showed that, compared to the control group, the follow-up group demonstrated better muscle strength, agility, and balance 32 . However, in our study, a positive change was only found in static balance, possibly linked to improved lower limb muscle strength, but no such change was identified in the measure of dynamic balance. It has been suggested by other researchers that static balance affects dynamic balance; however, our findings do not support this claim 29 , 30 , 33 , 34 , 35 , 36 , 37 , 38 . Although increased muscle strength beneficially impacts both types of balance, it is likely that an improvement in dynamic balance specifically also requires greater mobility 29 , 30 , 33 , 36 . Our rehabilitation programme included more exercises aimed at improving stability than mobility, which possibly explains this result. Furthermore, we know from clinical experience that it is very difficult for obese children with ID to perform dynamic balance exercises.

From the viewpoint of therapy, children with ID are a difficult group, as they tend to exhibit little interest in, or motivation for, exercise. Due to this, in future studies, it would be advisable to redesign the therapy programme by incorporating some incentivising and motivating elements, and by adding more exercises aimed at improving dynamic balance. For this purpose, various types of complex exercise programmes could be used. Mikołajczyk et al. proposed a programme comprising dual-task functional exercises performed on an unstable surface. These exercises increase the effectiveness of postural muscles, improve postural reflexes, and stimulate postural control in adolescents, contributing to improved dynamic balance 38 .

Finally, in line with the third detailed research question, this study compared the scores achieved by O Group and NW Group before and after the intervention in order to identify the effects of rehabilitation. The comparison of the groups before and after the intervention showed the only statistically significant differences in dynamic balance (timed up and go test); in both cases NW Group achieved better scores than O group. However no statistically significant differences in the effects of rehabilitation were found between O Group and NW Group, as reflected by the median for effects of rehabilitation amounting to zero in both groups. No statistically significant differences in the scores before and after the therapy and in the effects of rehabilitation were found between O and NW Groups in the measures of physical fitness (Eurofit Special Test specific trials) as well as static balance (single-leg stance test with eyes open/closed). It is likely that the differences in the dynamic balance, shown by the comparative assessment of the groups before the intervention, may be associated with the facts that body weight affects biomechanics of body movement as well as muscle strength 39 , and obesity-related limitations in joint mobility affect the ability to maintain balance 39 , 40 . Co-existing obesity leads to changes in the way a person moves and interacts with the ground, which has a negative effect on the ability to maintain dynamic balance 40 , 41 .

It is in fact possible to find research reports discussing the effects of various training programmes. However, in those cases the authors primarily focused on the factor of intellectual disability (e.g., its severity). As there are no reports on cohorts similar to ours (i.e., children with mild ID and with obesity or normal weight), we are unable to discuss our findings by reference to other similar works. The findings showed no significant differences between these two groups with regard to the effects of rehabilitation reflected by physical fitness or by static or dynamic balance. We suspect that this is because the children in O Group wanted to keep up with their normal-weight peers, and so participated in the rehabilitation programme with great commitment. However, we did not find any published research reports with related findings for discussion or to verify the results of our study. A review of the literature, however, showed that the relationship between BMI and physical fitness has been investigated. The effects of BMI on physical fitness, or more precisely on muscular endurance, muscle strength, flexibility, and aerobic capacity, were examined by Frey et al. 12 . The study showed that BMI affects muscle strength and endurance. Differences between the groups in these two measures were statistically significant, and poorer scores were achieved by the overweight and obese adolescents. The differences in flexibility and aerobic capacity between the children with normal weight and those with overweight or obesity were not statistically significant. The relationship between obesity and physical fitness in adolescents was also assessed by Salaun et al. In that study, the only significant difference was identified in the measure of trunk muscle strength between girls of normal weight and girls with obesity 19 .

While discussing these findings, it should be emphasised that this subject matter re-quires a great deal of attention as it is important for designing preventive measures and rehabilitation programmes tailored to the needs of children with ID, taking into account the BMI percentile. The findings showed that all children with mild ID, whether presenting with obesity or normal weight, should have an opportunity to participate in adequate rehabilitation programmes, as these lead to improvements in physical fitness and static balance, a fact that should be considered in all special education centres.

Limitations

This study presents some limitations. Firstly, it did not take into account a no-treatment control group of healthy children or children with mild ID, which would have made it possible to control more variables and attribute the changes to the intervention. Secondly, the findings are only applicable to children with mild ID. Hence, further research should assess the response of children with moderate and severe ID to the rehabilitation programme. Furthermore, this study involved a narrow age cohort of children with mild ID (aged 11–15 years). Hence, in the next stage of research, other age groups should also be assessed for the effects of the therapy programme. It will also be necessary to add more exercises that enable improvements in dynamic balance and muscular endurance into the rehabilitation programme, and to increase the intensity and frequency of exercise. Balance is important for children with ID, not only as a skill component, but also for health-related fitness. The present study focused exclusively on assessing static/dynamic balance reflected by specific physical skills; therefore, further research should be designed to also assess balance as a factor impacting health-related fitness. Moreover, future studies should utilise new research tools and questionnaires assessing physical fitness in relation to independence, as well as functioning in daily life. Furthermore, in future research, the rehabilitation programme should be redesigned to include incentivising and motivating components, and to match the capacities of children with ID. Ultimately, a follow-up study that includes a comparative analysis of different ethnicities from various continents could be conducted to broaden the subject matter of the research in the future.

Conclusions

This study showed that a six-month rehabilitation programme positively impacted the lower and upper limb muscle strength, flexibility, and static balance of an entire cohort of children with mild ID. The effects of rehabilitation on the measures of static and dynamic balance and physical fitness did not differ significantly between the children with obesity and those with normal weight. The findings suggest that all children with mild ID, whether presenting with obesity or normal weight, can achieve improvements in physical fitness and static balance if they have an opportunity to participate in this type of rehabilitation programme. This evidence is important from the viewpoint of clinical practice and, even more so, for preventive measures implemented in special education centres. Therefore, this information should be taken into account by those designing therapeutic programmes intended for children with mild ID that are provided in special education centres. Further research related to this subject matter should focus on children with moderate to severe ID, more age groups, and the long-term effects of the programme.

Data availability

The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.

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Andżelina Wolan-Nieroda & Agnieszka Guzik

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Conceptualisation, A.W–N. and A.G.; methodology, A.W–N., A.M., and A.G.; formal analysis, A.W., A.K, and A.W–N.; investigation, A.W–N., G.M. and A.W.; data curation, A.W–N., A.K. and A.W.; writing—original draft preparation, A.W–N., A.W., A.G, and G.M.; writing—review and editing, A.W–N., A.W., G.M., A.K., A.G. and A.M.; supervision, A.W–N. and A.M.; project administration, A.W–N. and A.G. All the authors read and agreed to the published version of the manuscript.

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Wolan-Nieroda, A., Wojnarska, A., Mańko, G. et al. Assessment of rehabilitation effects in children with mild intellectual disability. Sci Rep 13 , 15541 (2023). https://doi.org/10.1038/s41598-023-42280-1

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Comsi ® —a form of treatment that offers an opportunity to play, communicate and become socially engaged through the lens of nature—a single case study about an 8-year-old boy with autism and intellectual disability.

1. Introduction

1.1. theoretical background on how nature and animals are intended to enhance the treatment, 1.2. nature- and animal-assisted interventions, 1.3. the comsi ® model, 1.4. study aim, 2. materials and methods, 2.1. approach, 2.2. participant, 2.3. course of action, 2.4. assessment, 2.5. process notes, 2.6. parents’ description, 2.7. data analysis, 2.7.1. testing, 2.7.2. process notes and parents’ description, 3.1. background and early development, 3.2. testing in connection with the start of treatment, 3.3. williams’ abilities as described by his parents at the start of treatment, 3.3.1. emotional awareness and emotional stability, 3.3.2. contact, relationships, and the ability to share attention, 3.3.3. linguistic communication, 3.3.4. interests, 3.3.5. routine-dependent and structuring aids, 3.3.6. concentration and attention, 3.3.7. school, 3.3.8. sensory problems, 3.4. progress during treatment, 3.4.1. basic prerequisites for psychological development: trust, curiosity, and interest in exploring the environment, and regulation of emotional states, 3.4.2. ability to play, 3.4.3. social communication skills, 3.5. parents’ post-treatment description of william’s progress and development, 3.5.1. emotional awareness and emotional stability, 3.5.2. contact, relationships, and ability to share attention, 3.5.3. linguistic communication, 3.5.4. interests, 3.5.5. school, 3.5.6. continuing difficulties and problems, 3.6. results of post-treatment testing, 3.6.1. false beliefs, 3.6.2. cognition, 3.6.3. language, 4. discussion.

• Animals and nature form the platform and a microenvironment in which the treatment is based. Research on the importance of nature and animals for children’s development has found that various natural elements and processes stimulate children’s interest, imagination, and emotions, and that this supports associations, thinking, language, and the ability to reflect [ 42 , 99 , 100 ]. At present, there are no studies examining whether this also applies to children with autism, especially in terms of stimulating their capacities to play, communicate, and interact with other people with more engagement. Research shows that children with autism have difficulty with social contact, which also applies to people who suffer from severe life crises or severe stress. According to Supportive Environment Theory (SET), people under stress may find certain natural environments easier to relate to and manage [ 63 , 101 ], This applies to natural environments that are not too rich in impressions, and where a person can find ways to retreat and be by themselves when needed. According to SET, nature contains qualities that involve a gradient of challenges. COMSI ® is a method with a fixed structure. There are safe routines, starting with arrival at the farm for further transport to the campsite in nature. This natural site offers both a feeling of safety and a gradient of challenges, which makes it suitable for children with different needs. Here, however, it is important to point out that the children in the therapy group were at approximately the same level of cognitive and linguistic development and had approximately the same severity of autism (approximately moderate level on the Childhood Autism Rating Scale). Thus, it was easier for the children to interact more with each other over time and not become too hesitant or afraid due to a lack of understanding of what was happening in the interaction or because the environment and activities became too demanding.
• The therapists work to be responsive and provide gentle support. Staff see children with autism as “islands on the nature platform”. These “islands” are independent individuals who gradually receive support in building networks of interactions with the environment, where nature is the primary component. The children are individuals with strong integrity. They should be allowed to be at peace if they so wish and need. Their confidence in themselves and their surroundings needs to be built up, step by step, and this requires that they be allowed to explore the surroundings on their own terms to the extent possible. The therapists are trained to develop an intuitive sense of each child’s needs. With the help of gentle, flexible support from the therapists, children’s interactions with the environment can be developed. When the therapists discover that a child is taking positive steps forward in their development—for example by showing interest in something that is happening in the environment—they step in to help the child experience shared joy, coordinated attention, express their thoughts and feelings about what is happening. When they discover that a child cannot understand and interpret something they have seen or experienced, the therapists also explain and provide support. However, they step back to let the child take over again when they seem to be able to cope with the situation. We suggest that this nuanced and more well-toned social experience from being with therapist in nature, could have an effect on inner representations to emerge more easily, with Stern’s terminology so called RIGS (Representation of an Interaction that has become Generalized) [ 70 ]. Stern’s concept of RIGS refers to the way in which young children’s real experiences of interaction are organized in their psyche. Stern connects the emergence of RIGS to memory structures that represent such experiences. Children can begin to recall these models of “being with others” early on in the form of structures similar to stories. According to Stern, these stories contain different components, such as sensory impressions, actions, affects, and goals, and they form a temporally and thematically coherent unit. These experiences of interaction can then be generalized and form RIGS. One example of such a RIG could be “walking in the woods” under safe conditions with therapists. Models of being with others can thus start with being with nature.
• Children’s self-development follows two main trajectories [ 102 ]: The pursuit of autonomy—being able to understand and master the world around one to avoid falling victim to unpredictable or unknown forces—includes the pursuit of knowledge, the desire to create, and mastery of everyday situations. The pursuit of homonymy means belonging to a group, family, work community, sports association, or any other form of social community and can also include a type of belonging to a religious group or nature. Nature, coupled with a therapist who serves as a safe haven, can thus be a place where children can exercise autonomy but are also able to develop a type of necessary security and belonging. This is called place attachment and can develop when the conditions of person, place, and process are right [ 103 ]. Being able to develop a sense of togetherness and security in certain places is also considered a part of children’s natural development [ 104 ].
• Collaboration with parents both before COMSI ® treatment and during and afterward builds a bridge between therapist and parents. Children can sense this bridge of hope and trust, and it can also help the method to work. It is also important to assemble the group together correctly. Our experience here is that group members need to be at approximately the same developmental level for interaction between them to optimally stimulate their functions and for development to progress satisfactorily.

5. Conclusions

Author contributions, institutional review board statement, informed consent statement, data availability statement, acknowledgments, conflicts of interest.

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Byström, K.; Wrangsjö, B.; Grahn, P. COMSI ® —A Form of Treatment That Offers an Opportunity to Play, Communicate and Become Socially Engaged through the Lens of Nature—A Single Case Study about an 8-Year-Old Boy with Autism and Intellectual Disability. Int. J. Environ. Res. Public Health 2022 , 19 , 16399. https://doi.org/10.3390/ijerph192416399

Byström K, Wrangsjö B, Grahn P. COMSI ® —A Form of Treatment That Offers an Opportunity to Play, Communicate and Become Socially Engaged through the Lens of Nature—A Single Case Study about an 8-Year-Old Boy with Autism and Intellectual Disability. International Journal of Environmental Research and Public Health . 2022; 19(24):16399. https://doi.org/10.3390/ijerph192416399

Byström, Kristina, Björn Wrangsjö, and Patrik Grahn. 2022. "COMSI ® —A Form of Treatment That Offers an Opportunity to Play, Communicate and Become Socially Engaged through the Lens of Nature—A Single Case Study about an 8-Year-Old Boy with Autism and Intellectual Disability" International Journal of Environmental Research and Public Health 19, no. 24: 16399. https://doi.org/10.3390/ijerph192416399

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Case 2: An 11-year-old girl with aggressive behaviour and intellectual impairment

An 11-year-old Caucasian girl was referred for evaluation of aggressive behaviour that had worsened over the past two years. She experienced frequent outbursts of anger and would scream or bite when she became upset. She was cognitively delayed and could not independently perform activities of daily living such as bathing and eating. Attempts at toilet training were unsuccessful. She exhibited repetitive mannerisms such as hand flapping, eye blinking, repeated hand washing and running in circles. Socialization skills were restricted and eye contact was poor. Family history was significant for four brothers with developmental delay, a maternal aunt with premature menopause, and history of gait instability and tremors in her maternal grandfather since 40 years of age. There was no history of consanguinity. No complications were reported during pregnancy or birth. Her motor milestones were normal. Although she exhibited language delay, she could engage in a conversation with diminished vocabulary.

On physical examination, vital signs were normal. Subtle facial dysmorphism was present ( Figure 1 ). Her head was normocephalic, and cardiac and pulmonary examinations were unremarkable. The patient was noted to be intellectually impaired, hyperactive, had poor eye contact and displayed repetitive behaviour. The remainder of the neurological examination (cranial nerves, motor, sensory and reflexes) was normal.

Patient’s photograph demonstrating subtle dysmorphic features including a long face, thin upper lip and long philtrum

CASE 2 DIAGNOSIS: FRAGILE X SYNDROME

This case is a classic presentation of fragile X syndrome (FXS). FXS is caused by a mutation of the fragile X mental retardation 1 ( FMR1 ) gene on Xq27.3. The vast majority of cases occur as a result of unstable expansion of the CGG repeat in the FMR1 gene. The presence of >200 repeats is associated with hypermethylation, leading to transcriptional silencing and a decrease or absence of the gene product, fragile X mental retardation protein ( 1 ). The diagnosis of FXS is made by assessing the number of CGG repeats using polymerase chain reaction analysis, usually in conjunction with Southern blot analysis, which evaluates the methylation status of the gene. The patient in the present case was genetically confirmed to have the full mutation (667 repeats of CGG), along with four of her brothers.

FXS is the most common cause of inherited intellectual disability and is strongly associated with autism ( 1 ). It may present with features of pervasive developmental disorder including language delay, stereotypic behaviours and social impairment. Children with FXS often experience scholastic problems due to autism in addition to the underlying intellectual disability, and are frequently placed in special education classes or are homeschooled. Other features include attention deficit hyperactivity disorder, hyperextensible joints, mitral valve prolapse, flat feet, hypersensitivity to sensory stimuli and hypotonia ( 1 ). Many patients with FXS, particularly boys, develop seizures in early childhood ( 1 ). Individuals with FXS often have a characteristic physical appearance including macrocephaly, a long face with a prominent forehead and large ears. Postpubertal males can develop macro-orchidism. Similar to our patient, females affected with FXS may exhibit subtle dysmorphic features. As a result of random X inactivation and presence of FMR1 from the normal X chromosome, females with FXS may develop an attenuated phenotype ( 1 ). It may, thus, be challenging to suspect FXS in a girl solely based on clinical presentation.

Family history may provide important clues to the diagnosis of FXS. While the presence of >200 CGG repeats leads to FXS, patients with 55 to 200 repeats (‘premutation’) have a different clinical phenotype. Premutation carrier males often have mild cognitive deficits and may develop fragile X-associated tremor/ataxia syndrome (FXTAS), which is a Parkinson’s-like condition that presents with gait instability and postural tremors. Premutation carrier females may develop premature ovarian failure, anxiety and depression ( 2 ). The symptoms reported in the patient’s maternal grandfather and aunt were suspicious for FXTAS and premature ovarian failure, respectively. Taking a thorough history is vital to obtain these important clues, which may assist in evaluation and diagnosis.

Interventions, such as early developmental stimulation, physical therapy, occupational therapy, and speech and language therapy, are key to the management of children with FXS. Stimulants and anti-depressants can be prescribed for behavioural symptoms including hyperactivity, inattention and mood disturbances. Children with seizures should be treated with anticonvulsants. Targeted therapeutic options are currently being evaluated, including R-baclofen, which may have a role in decreasing seizures, improving autistic behaviours and decreasing social impairment ( 2 ). Families should be offered genetic counselling to determine the extent of the mutation and risk of transmission because there are implications for the diagnosis on seemingly unaffected family members.

In summary, FXS remains the most common cause of inherited intellectual disability and should be a part of the evaluation of any child with unexplained developmental delay. Our patient exhibited some of the physical characteristics of FXS, but the presence of pervasive features along with the intellectual disability and a strong family history favoured a diagnosis of FXS. It is important to consider FXS in girls presenting with intellectual disability because the clinical features may be more subtle compared with boys.

CLINICAL PEARLS

• FXS is the most common inherited cause of intellectual disability.
• Characteristic features of FXS include physical characteristics such as a long face, large ears and macro-orchidism (in postpubertal males), as well as autism, seizures and attention deficit hyperactivity disorder. Premutation carriers can present with FXTAS (males) and premature ovarian failure (females).
• FXS should be considered as a potential diagnosis in girls presenting with unexplained intellectual disability because other features of the disease may be less conspicuous.

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Theory of mind development in school environment: A case of children with mild intellectual disability learning in inclusive and special education classrooms

Affiliations.

• 1 Department of Education, University of Warsaw, Warsaw, Poland.
• 2 Department of Philosophy, Jagiellonian University, Cracow, Poland.
• PMID: 31069902
• DOI: 10.1111/jar.12616

Background: This longitudinal study examines the extent to which a school classroom (inclusive vs. special education) is meaningful for theory of mind (ToM) development among children with mild intellectual disability.

Materials and methods: The participant group consisted of 166 primary school-aged children (M = 8.1, SD = 0.99), 79 of whom attended inclusive classrooms; the remaining 87 were in special education classrooms.

Results: Although all children developed ToM over time, children's learning of ToM in inclusive classrooms was significantly greater than that seen in special classrooms. The difference remained significant after controlling for age. The present authors have compared children's individual and family characteristics, but there were almost no differences between groups.

Conclusions: The present authors discuss the results in the light of their importance for children's cognitive and social development. The implications for children's education are also considered.

Keywords: children; inclusive classroom; mild intellectual disability; special education classroom; theory of mind.

© 2019 John Wiley & Sons Ltd.

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Teaching Children with Intellectual Disabilities: Analysis of Research-Based Recommendations

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History and Epidemiology of Intellectual Disability

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• Pallab K. Maulik 3 , 4 , 5 , 6 , 7 ,
• Catherine K. Harbour 8 &
• Jane McCarthy 9 , 10  

Part of the book series: Autism and Child Psychopathology Series ((ACPS))

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The chapter outlines the history of intellectual disability over the centuries and highlights some of the key legislations, policies and scientific understanding that have evolved over the past centuries, which have also influenced the different diagnostic systems. The section on epidemiology gives a broad overview of some factors that determine the epidemiology of the condition, keeping in perspective the incidence, prevalence and mortality estimates; aetiology; and knowledge about health services research. The gaps in knowledge and future research are discussed.

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Maulik, P.K., Harbour, C.K., McCarthy, J. (2024). History and Epidemiology of Intellectual Disability. In: Matson, J.L. (eds) Handbook of Psychopathology in Intellectual Disability. Autism and Child Psychopathology Series. Springer, Cham. https://doi.org/10.1007/978-3-031-66902-6_1

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