Early verbal disability in children with Duchenne muscular dystrophy

Wechsler Scale Intelligence Testing in Males with Dystrophinopathies: A Review and Meta-Analysis

BACKGROUND

Intelligence scores in males with Duchenne Muscular Dystrophy (DMD) and Becker Muscular Dystrophy (BMD) remain a major issue in clinical practice. We performed a literature review and meta-analysis to further delineate the intellectual functioning of dystrophinopathies.

METHOD

Published, peer-reviewed articles assessing intelligence, using Wechsler Scales, of males with DMD or BMD were searched from 1960 to 2022. Meta-analysis with random-effects models was conducted, assessing weighted, mean effect sizes of full-scale IQ (FSIQ) scores relative to normative data (Mean = 100, Standard Deviation = 15). Post hoc we analysed differences between performance and verbal intelligence scores.

RESULTS

43 studies were included, reporting data on 1472 males with dystrophinopathies; with FSIQ scores available for 1234 DMD (k = 32) and 101 BMD (k = 7). DMD males score, on average, one standard deviation below average (FSIQ = 84.76) and significantly lower than BMD (FSIQ = 92.11). Compared to a previous meta-analysis published in 2001, we find, on average, significantly higher FSIQ scores in DMD.

CONCLUSION

Males with Duchenne have, on average, significantly lower FSIQ scores than BMD males and the general population. Clinicians must consider lower intelligence in dystrophinopathies to ensure good clinical practice.

Neurodevelopmental, behavioral, and emotional symptoms common in Duchenne muscular dystrophy

INTRODUCTION

We studied neurodevelopmental and behavioral/emotional symptoms in patients with Duchenne muscular dystrophy (DMD).

METHODS

Retrospective case series of neurodevelopmental and behavioral/emotional symptoms obtained through review of systems of 700 DMD patients in relation to dystrophin gene mutations.

RESULTS

The most common symptoms encountered were emotional/behavioral dysregulation (38.7%), inattention/hyperactive features (31.4%), obsessive and compulsive features (25.0%), and language/speech delays (24.4%). Most patients (72.7%) had at least one symptom. Patients with mutations near the 3' end of the dystrophin gene were at higher risk for developing inattention/hyperactive features, language/speech delays, and global intellectual delays. Those with mutations between exon 31 and 79 had higher risk of clustering of symptoms when compared with those upstream of exon 30.

DISCUSSION

Neurodevelopmental, emotional, and behavioral symptoms are common comorbidities in DMD. There is higher prevalence of inattention/hyperactive features, language/speech delays, and global intellectual delays in genotypes affecting the 3' end of the dystrophin gene.

Profile of cognitive function in adults with duchenne muscular dystrophy

BACKGROUND

Several studies have examined intellectual functioning of boys with duchenne muscular dystrophy (DMD). However, little is known about the remaining cognitive weaknesses in adults with DMD.

OBJECTIVE

The purpose of this study was to investigate the profile of cognitive functioning that is characteristics of adults with DMD.

METHODS

Twenty-four subscales from the Wechsler Adult Intelligence Scale III (WAIS-III), the Clinical Assessment for Attention (CAT), and the Wechsler Memory Scale Revised (WMS-R) were used to assess participants with DMD (N=15; mean age=30.4years).

RESULTS

Scores for Picture Completion, Arithmetic, Matrix Reasoning, Symbol Search, Letter-Number Sequencing, and Digit Span of the WAIS-III; all CAT scores, and Logical Memory and Delayed Logical Memory from the WMS-R were significantly deficient in adults with DMD in comparison to the normal population.

CONCLUSION

The ability to sequentially process auditory and visual information remains impaired in adults with DMD.

Cognitive and Neurobehavioral Profile in Boys With Duchenne Muscular Dystrophy

Duchenne muscular dystrophy is a progressive neuromuscular condition that has a high rate of cognitive and learning disabilities as well as neurobehavioral disorders, some of which have been associated with disruption of dystrophin isoforms. Retrospective cohort of 59 boys investigated the cognitive and neurobehavioral profile of boys with Duchenne muscular dystrophy. Full-scale IQ of < 70 was seen in 27%; learning disability in 44%, intellectual disability in 19%; attention-deficit/hyperactivity disorder in 32%; autism spectrum disorders in 15%; and anxiety in 27%. Mutations affecting Dp260 isoform and 5'untranslated region of Dp140 were observed in 60% with learning disability, 50% intellectual disability, 77% with autism spectrum disorders, and 94% with anxiety. No statistically significant correlation was noted between comorbidities and dystrophin isoforms; however, there is a trend of cumulative loss of dystrophin isoforms with declining full-scale IQ. Enhanced psychology testing to include both cognitive and neurobehavioral disorders is recommended for all individuals with Duchenne muscular dystrophy.

Neuropsychological and neurobehavioral functioning in Duchenne muscular dystrophy: a review

Duchenne muscular dystrophy (DMD) is a genetic condition affecting predominantly boys that is characterized by fatal muscle weakness. While there is no cure, recent therapeutic advances have extended the lifespan of those with DMD considerably. Although the physiological basis of muscle pathology is well-documented, less is known regarding the cognitive, behavioral, and psychosocial functioning of those afflicted. Several lines of evidence point to central nervous system involvement as an organic feature of DMD, challenging our view of the disorder as strictly neuromuscular. This report provides a review of the literature on neuropsychological and neurobehavioral functioning in DMD. Recent research identifying associations with DMD and neuropsychiatric disorders is also discussed. Lastly, the review presents implications of findings related to nonmotor aspects of DMD for improving the quality of life in those affected. While the literature is often contradictory in nature, this review highlights some key findings for consideration by clinicians, educators and parents when developing therapeutic interventions for this population.

Specific profiles of neurocognitive and reading functions in a sample of 42 Italian boys with Duchenne Muscular Dystrophy

A group of 42 Italian boys with Duchenne Muscular Dystrophy was compared with a control group of 10 boys with Spinal Muscular Atrophy and Osteogenesis Imperfecta on tests assessing general intellectual ability, language, neuropsychological functions, and reading skills with the aim of describing a comprehensive profile of the various functions and investigating their interrelationships. The influence of general intellectual level on performance was analyzed. Further, correlations between various neuropsychological measures and language performances were computed for the group with Duchenne Muscular Dystrophy, as well as the correlations between reading scores and other cognitive and linguistic measures. A general lowering in VIQ, PIQ, and FSIQ scores was found to characterize the group with Duchenne Muscular Dystrophy. Expressive language skills were within the normal range, while syntactic and grammatical comprehension were significantly impaired. The presence of below-average reading performances was further confirmed. However, unlike previous studies on irregular orthographies, the present results show that (a) the mild reading difficulties found in the sample essentially concern speed rather than accuracy; (b) they concern word rather than nonword reading; (c) lower reading performances are related to lower scores in general IQ; (d) no correlations emerge with phonological abilities, verbal short-term memory, or working memory, but rather with long-term memory and lexical skills. This may suggest that language-specific effects modulate the cognitive expressions of Duchenne Muscular Dystrophy and raises the possibility that the dysfunctions underlying the reading difficulties observed in affected readers of regular orthographies involve different neurocognitive systems than the cortico-cerebellar circuits usually invoked.

Intellectual and behavioral functioning in a South african cohort of boys with duchenne muscular dystrophy

The authors describe the neurocognitive and behavioral phenotype of 16 South African children (ages 4-16 years) with Duchenne muscular dystrophy, compared with 13 controls. The preschool group performed significantly worse than the controls in measures of general developmental performance. The school-age group showed no significant differences in general intellectual abilities. However, our data identified that boys with Duchenne muscular dystrophy experience mild cognitive dysfunction across multiple domains, including visual memory, and verbal and nonverbal executive functioning. Parental reports of 11 boys with the disorder revealed high rates of general behavioral problems (54.5%). The cognitive profile of boys with Duchenne muscular dystrophy in South Africa is similar to that described elsewhere in the world. Behavioral problems in our cohort were higher than previously reported. This may be partially explained by the poor socioeconomic background of the majority of the cohort.

Dystrophin gene mutation location and the risk of cognitive impairment in Duchenne muscular dystrophy

BACKGROUND

A significant component of the variation in cognitive disability that is observed in Duchenne muscular dystrophy (DMD) is known to be under genetic regulation. In this study we report correlations between standardised measures of intelligence and mutational class, mutation size, mutation location and the involvement of dystrophin isoforms.

METHODS AND RESULTS

Sixty two male subjects were recruited as part of a study of the cognitive spectrum in boys with DMD conducted at the Sydney Children's Hospital (SCH). All 62 children received neuropsychological testing from a single clinical psychologist and had a defined dystrophin gene (DMD) mutation; including DMD gene deletions, duplications and DNA point mutations. Full Scale Intelligence Quotients (FSIQ) in unrelated subjects with the same mutation were found to be highly correlated (r = 0.83, p = 0.0008), in contrast to results in previous publications. In 58 cases (94%) it was possible to definitively assign a mutation as affecting one or more dystrophin isoforms. A strong association between the risk of cognitive disability and the involvement of groups of DMD isoforms was found. In particular, improvements in the correlation of FSIQ with mutation location were identified when a new classification system for mutations affecting the Dp140 isoform was implemented.

SIGNIFICANCE

These data represent one of the largest studies of FSIQ and mutational data in DMD patients and is among the first to report on a DMD cohort which has had both comprehensive mutational analysis and FSIQ testing through a single referral centre. The correlation between FSIQ results with the location of the dystrophin gene mutation suggests that the risk of cognitive deficit is a result of the cumulative loss of central nervous system (CNS) expressed dystrophin isoforms, and that correct classification of isoform involvement results in improved estimates of risk.

Delayed developmental language milestones in children with Duchenne's muscular dystrophy

OBJECTIVES

To document the attainment of developmental milestones in children with Duchenne's muscular dystrophy (DMD) and to determine whether early delays are associated with later performance on measures of cognition.

STUDY DESIGN

Retrospective parental report was utilized to document the acquisition of 10 common developmental milestones in children with DMD (n = 130) and their unaffected siblings (n = 59). Children completed tests of cognitive functioning.

RESULTS

Parents rated children with DMD as delayed on achieving both language and motor milestones more frequently than their unaffected siblings. Furthermore, those children with DMD who were rated as late talkers or late walkers performed more poorly on tests of cognitive function than their on-time peers.

CONCLUSIONS

In addition to the commonly reported delays in motor milestones, the current study documents delays in the acquisition of language milestones as well. These early delays are associated with significant impairments in later cognitive functioning.

Survey of behaviour problems in children with neuromuscular diseases

Previous research on clinic samples has suggested that children with neuromuscular diseases may be affected by mental health problems. The aim of this study was to establish the carer-reported prevalence of social, communication, and behavioural problems in middle childhood in a total population with neuromuscular diseases. From a target population of 111, 82 carers of children aged 5-13 years with a diagnosed neuromuscular disease living in the Northern Region of UK were interviewed about service utilisation and needs, and 66 completed the Strengths and Difficulties Questionnaire, Social Communication Questionnaire and Children's Communication Checklist. Two-fifths of children scored above the clinical cut-off on at least one questionnaire. These results were significantly higher than are reported for national and normally developing samples. Nine out of 82 had a diagnosis of autism spectrum disorder. Carers of children with problems reported significantly higher levels of unmet need. Behaviour, social and communication problems are common in children with neuromuscular diseases and Regional Neuromuscular Clinics should consider mental health screening and assessment.

Duchenne muscular dystrophy: alpha-dystroglycan immunoexpression in skeletal muscle and cognitive performance

The Duchenne muscular dystrophy (DMD) is a muscular dystrophy with cognitive impairment present in 20-30% of the cases. In the present study, in order to study the relationship between the alpha-dystroglycan (alpha-DG) immunostaining in skeletal muscle and cognitive performance in DMD patients, 19 were assessed. Twelve patients performed the intelligence quotient (IQ) below the average. Among the 19 patients, two were assessed by the Stanford-Binet test and 17 by Wechsler Intelligence Scale for Children-III (WISC-III). Nine patients performed a verbal IQ below the average, only three patients performed an average verbal IQ. The muscle biopsies immunostained with antibodies to alpha-DG showed that 17 patients presented a low expression, below 25% of the total fibers. Two patients presented alpha-DG immunostaining above 40% and an IQ within the average. No significant statistical relationship was demonstrated among total IQ, verbal IQ and execution IQ and alpha-DG immunostaining at these patients muscle samples.

Spirometry is affected by intelligence and behavior in Duchenne muscular dystrophy

Children with Duchenne muscular dystrophy (DMD) have progressive respiratory muscle weakness. Spirometry monitors progress, but is effort-dependent. Intelligence quotients (IQ) average one standard deviation below normal, and behavioral disturbance is common. Our aim was to assess if impaired intelligence or behavior influences spirometry in children with DMD, and if computerized visual incentives (CVI) are beneficial. Forty-seven boys with DMD, of mean age 12.6 years (range, 6-19), were recruited. Full-scale, performance, and verbal IQ, and parent-and-teacher-reported oppositional behavior scores, were recorded. Each was divided into moderate, mild, and no impairment groups. A randomized crossover design was applied to performing spirometry with or without CVI first. A Jaeger Masterscope (version 4.60) was used. Linear regression defined the relationship between spirometry and both IQ and behavior scores. The paired Student's t- test compared spirometry performed with and without CVI for the overall group and subgroups. Boys with DMD can adequately perform spirometry. There is an association between %FEV1 and %FVC with full-scale (r = 0.50, P = 0.002; r = 0.49, P = 0.003, respectively), performance (r = 0.68, P < 0.0005; r = 0.68, P < 0.0005, respectively) and verbal (r = 0.39, P = 0.043; r = 0.36, P = 0.037, respectively) IQ, but not with parent (P = 0.77, P = 0.70, respectively) or teacher (P = 0.90, P = 0.90, respectively)-reported oppositional behavior scores. The effect of CVI was significant in those with moderate full-scale (P = 0.03), performance (P = 0.002), and verbal (P = 0.02) intellectual impairment, and moderately severe teacher-reported oppositional behavior (P = 0.02). In conclusion, spirometry results are related to intelligence in DMD. Using CVI improves the FVC obtained in those with moderate intellectual or behavioral impairment.

Investigation of Poor Academic Achievement in Children with Duchenne Muscular Dystrophy

Duchenne Muscular Dystrophy (DMD) is a neurogenetic developmental disorder that presents with progressive muscular weakness. It is caused by a mutation in a gene that results in the absence of specific products that normally localize to muscle cells and the central nervous system (CNS). The majority of affected individuals have IQs within the normal range, generally with lower verbal than performance IQ scores. Prior work has demonstrated selective deficits on tests of verbal span and immediate memory. For the current study, 26 boys with DMD (and normal intellectual function) and their unaffected siblings were evaluated. Paired comparisons demonstrated that the children with DMD had significantly poorer academic achievement scores than their siblings, even though their vocabulary levels and home and educational environments were comparable. Children with DMD also had more behavioral concerns, physical disabilities, and poorer verbal memory spans. Linear regression indicated that behavioral concerns, executive function, and physical disability did not contribute substantially to academic performance, whereas performance on verbal span did. DMD presents with a selective developmental aberration in verbal span that has wide-ranging consequences on learning skills.

Brain function in Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is the second most commonly occurring genetically inherited disease in humans. It is an X-linked condition that affects approximately one in 3300 live male births. It is caused by the absence or disruption of the protein dystrophin, which is found in a variety of tissues, most notably skeletal muscle and neurones in particular regions of the CNS. Clinically DMD is characterized by a severe pathology of the skeletal musculature that results in the premature death of the individual. An important aspect of DMD that has received less attention is the role played by the absence or disruption of dystrophin on CNS function. In this review we concentrate on insights into this role gained from investigation of boys with DMD and the genetically most relevant animal model of DMD, the dystrophin-deficient mdx mouse. Behavioural studies have shown that DMD boys have a cognitive impairment and a lower IQ (average 85), whilst the mdx mice display an impairment in passive avoidance reflex and in short-term memory. In DMD boys, there is evidence of disordered CNS architecture, abnormalities in dendrites and loss of neurones, all associated with neurones that normally express dystrophin. In the mdx mouse, there have been reports of a 50% decrease in neurone number and neural shrinkage in regions of the cerebral cortex and brainstem. Histological evidence shows that the density of GABA(A) channel clusters is reduced in mdx Purkinje cells and hippocampal CA1 neurones. At the biochemical level, in DMD boys the bioenergetics of the CNS is abnormal and there is an increase in the levels of choline-containing compounds, indicative of CNS pathology. The mdx mice also display abnormal bioenergetics, with an increased level of inorganic phosphate and increased levels of choline-containing compounds. Functionally, DMD boys have EEG abnormalities and there is some preliminary evidence that synaptic function is affected adversely by the absence of dystrophin. Electrophysiological studies of mdx mice have shown that hippocampal neurones have an increased susceptibility to hypoxia. These recent findings on the role of dystrophin in the CNS have implications for the clinical management of boys with DMD.

Poor verbal working memory across intellectual level in boys with Duchenne dystrophy

OBJECTIVE

To determine whether all boys with Duchenne muscular dystrophy (DMD) have a similar verbal and memory profile of skills, or whether only a subset is affected, and to determine whether the weak areas in their profile are substantially different from a control group.

METHODS

Performance of patients with DMD on neuropsychological tests of verbal and memory skills was examined in two ways. Standardized test scores for 80 boys with DMD (estimated IQ range, 70 to 160) were ranked individually from worst to best, and the individual rankings were compared across the group using Friedman rank analysis. Additionally, performance of 41 boys with DMD was compared with that of their sibling control subjects of similar age and estimated IQ using multivariate analysis of variance.

RESULTS

Individual cognitive profiles were significantly similar among the subjects with DMD, such that for most subjects digit span, story recall, and comprehension were the tests on which each performed most poorly. This finding remained true regardless of whether they were of high or low intellectual function. In contrast, no significant cognitive profile was found among their sibling control subjects, and when compared with their siblings, the DMD group scored significantly more poorly on digit span, comprehension, and story recall, but not on other verbal and memory measures.

CONCLUSIONS

Boys with DMD have a specific cognitive profile, regardless of their general level of cognitive function. Specifically, boys with DMD performed more poorly on tests requiring attention to complex verbal information than they did on other verbal or memory measures. The possibility that the missing dystrophin brain products may contribute to selective cognitive processing is considered.

The psychosocial and cognitive impact of Duchenne's muscular dystrophy

Duchenne's muscular dystrophy (DMD) is the most prevalent and devastating of neuromuscular disorders. Children given this diagnosis not only face inevitable deterioration of physical functioning, but they also become susceptible to emotional/behavioral problems, as well as reduced cognitive functioning and learning problems. This article (1) reviews the emotional/behavioral issues that may impact the child with DMD and the affected child's family members and caregivers; (2) examines the research describing the cognitive and learning issues associated with DMD; (3) provides recommendations for physicians who work with these families; and (4) recommends directions for future research that will help to further elucidate emotional/behavioral issues and cognitive and learning correlates of DMD.

Reading ability and processing in Duchenne muscular dystrophy and spinal muscular atrophy

We analysed the reading abilities and processing of 21 children with Duchenne muscular dystrophy (DMD), 11 matched children suffering from spinal muscular atrophy (SMA) and 42 children receiving normal education. The principal result observed was that the DMD children exhibited a reading age which was significantly lower than the SMA children compared with their chronological age. These learning disabilities were not related to a deficit in non-verbal performance intelligence, but psycholinguistic evaluation showed a deficit in verbal intelligence, especially in the Similarities and Arithmetic WISC-R subtests, in phonological abilities, oral word repetition, and in digit span score. The results for the DMD children were heterogeneous, and ranged from normal to greater or lesser involvement. In an attempt to clarify the nature of this reading impairment in DMD children, the three groups (DMD, SMA, and normal control children) were tested by reading aloud a list of single words and non-words. The DMD children were significantly impaired in reading non-words, suggesting reading disability similar to dysphonetic dyslexia, the most frequent subtype of developmental dyslexia. These results are discussed in the light of psychometric data available for our DMD population and in the light of previous studies. The practical consequences of diagnosis on rehabilitation are very important. The precise description of the cognitive deficits seen in DMD is of value for future clinical and genetic studies.

End of life care in Duchenne muscular dystrophy

End of life care for patients with Duchenne muscular dystrophy (DMD) has become increasingly complex because of new technologies, changes in medical personnel over periods of time, emergence of home health care systems, and increasing patient and family autonomy in decision-making. In this review, we discuss the medical problems, particularly respiratory and cardiac failure, faced by DMD patients. Current concepts concerning the evaluation and options for treatment of these problems are presented as well as the ethical issues involved in the care of the DMD patient. These issues include the medical indications for treatment, patient preferences, quality-of-life issues, and contextual features related to legal, institutional, religious, geographic, cultural, social, and financial factors. We also present our experience at Loma Linda University Medical Center over the past 10 years in the development of a home mechanical ventilation program for DMD patients and an algorithm for the evaluation of these patients. Many patients with DMD do well on long-term ventilation, but some find that their quality of life is less than desirable and choose to discontinue this method of life-prolongation. Many of these new options are very expensive, making the decision to use them a difficult one. Ultimately, these are societal issues that require clear reflection on matters of resource allocation that should be performed by health care professionals, citizens, and health planners.

Cognitive functions in Duchenne muscular dystrophy: a reappraisal and comparison with spinal muscular atrophy

In order to clarify cognitive functions in Duchenne muscular dystrophy (DMD), we performed a new controlled neuropsychological study. IQ (WISC-R), verbal skills (fluency, confrontation naming and syntax comprehension) and memory abilities (BEM) were studied in two matched groups; 24 DMD children and 17 spinal muscular atrophy (SMA) children aged 12-16 yr. A significant difference appeared between the DMD and SMA patients: only in the DMD group were there significant disabilities in certain specific functions and normal scores in others. Despite similar education, the DMD children more often had significantly greater learning disabilities. There were more DMD left-handers. Verbal IQ was significantly low whereas performance IQ was at a normal level. DMD children also performed poorly in reading tasks and in some memory functions such as story recall and verbal recognition. Specific cognitive disabilities in certain DMD children, not seen in SMA children, suggest a relationship with a DMD genetic disorder.

The family's experience of living with a child with Duchenne muscular dystrophy

An ethnographic inquiry was conducted to better understand the experience of families living with a child with Duchenne muscular dystrophy. Participant-observation and in-depth interviews were used to collect data. Six themes emerged as primary descriptors of the experience: (a) Disillusionment: The Erosion of the Hope for Normalcy; (b) Society Confirms the Impossibility of Normalcy; (c) Dynamics of the Family: Who's Disabled Anyway?; (d) A Smaller World; (e) Letting Go or Hanging On; and (f) Things Must Change. Implications of these themes are discussed in terms of need for counseling and support services for families, in-service education for health professionals, and activities for children diagnosed with Duchenne muscular dystrophy.

Head circumference and intellectual performance of patients with Duchenne muscular dystrophy

The head circumferences of 64 patients with Duchenne muscular dystrophy were measured and found to be greater than those of a normal population. The patients had relative, and in 12 cases, absolute macrocephaly. 47 of the 64 patients underwent intelligence testing and were found to be significantly intellectually impaired, particularly in verbal and language skills. There was no correlation between head circumference or absolute macrocephaly and intellectual performance. The cause of macrocephaly in these patients is unknown and its relevance to the aetiology of intellectual impairment in Duchenne muscular dystrophy is not yet clear.

Early development of boys with Duchenne muscular dystrophy

Thirty-three boys with Duchenne muscular dystrophy (DMD) and a mean age of 3.4 years were assessed with the Griffiths Developmental Scales, the Reynell Language Scales and the British Picture Vocabulary Scales at six-monthly intervals over a one-year period. The boys showed developmental delay, which was most severe in the locomotor and language areas. The locomotor quotients deteriorated over time, but the other quotients did not. Maternal intelligence, home environment and social class had little effect on the aetiology of the developmental delay, and the behavioural problems seen in young boys with DMD may be secondary to it.

Intellectual function in muscular dystrophies

Intellectual function was studied in 28 boys with Duchenne dystrophy, 12 patients with facioscapulohumeral-type and 10 patients with limb-girdle-type muscular dystrophy. A definite relationship between intelligence level and the type of muscle disease was found. The more severe the genetic damage manifested by the rapidity of progression of muscular dystrophy the more definite the affection of the CNS manifesting as mental deficit. The factors influencing the level and structure of intelligence seem to exert their effect before the manifestation of muscle lesions.

The diagnosis of muscular dystrophy in patients referred for language delay

The diagnosis of muscular dystrophy is usually made on the basis of gait difficulties or a history of late achievement of normal motor milestones. Other well-described delays, notably in the area of expressive language skills, can provide additional clues to this diagnosis. We present three patients referred to The Developmental Evaluation Clinic because of problems with expressive language observed in school, who ultimately were found to have muscular dystrophy. They are presented to underscore the association of expressive language delay in patients with muscular dystrophy, and to stress the importance of a thorough motor evaluation in children with speech problems.

Neuropsychological impairment in Duchenne muscular dystrophy

Fourteen younger (ages 6 to 10 years) and 11 older (ages 11 to 16 years) Duchenne Muscular Dystrophy (DMD) patients were tested with the WISC-R and neuropsychological language, visual-motor, and motor tasks. Older boys had an average IQ; younger boys were in the low average IQ range. Younger DMD boys were inferior to the older DMD group on tasks requiring some language and attentional-organizational skills, but not on visual-motor tasks. Older DMD boys were inferior on motor tasks. Results suggest that the reported low cognitive skills in DMD patients are not fixed or global, but reflect selective deficits in the younger boys. Possible bases for age differences in performance are discussed.

IQ, prognosis and Duchenne muscular dystrophy

The verbal scales (VS-IQ) of the IQs of 25 boys with Duchenne muscular dystrophy, the total population in Western Australia older than five yrs, were recorded. All the results of those 20 yrs of age and older lay within the normal range. The mean VS-IQ of those less than 20 yrs and less than 18 yrs is compared with the mean VS-IQ of those 20 yrs and older, and 18 yrs and older, respectively. The differences between the groups are statistically significant, and it is postulated that an active management programme has revealed a population of boys with normal intelligence who have an increased chance of prolonged survival.