Specific cognitive deficits are common in children with Duchenne muscular dystrophy

A neuropsychological assessment was conducted to study cognition, with emphasis on memory, information processing/learning ability, and executive functions in boys with Duchenne muscular dystrophy (DMD). A group of 20 boys with DMD, aged 7 to 14 years (mean age 9 years 5 months, SD 2 years 2 months), was contrasted with 17 normally developing age-matched comparison individuals, using specific neuropsychological tests (Block Span, Digit Span, Story Recall, Rey Auditory Verbal Learning Test, Rey Complex Figure Test, Spatial Learning Test, Verbal Fluency, Trail Making Test, Tower of London, Memory for Faces, and Raven's Coloured Progressive Matrices). The DMD group performed significantly worse on all aspects of memory, learning, and executive functions. There was no significant difference in general intellectual ability between the two groups. Analyses of group differences indicate that problems in short-term memory are the most apparent, suggesting specific cognitive deficits. The differences between the groups were similar for both verbal-auditory and visuospatial tests, thus contradicting the idea that cognitive deficits are related to type of stimulus presented. It is concluded from this study that short-term memory deficits might play a critical role in the cognitive impairment and intellectual development seen in those with DMD.