Neuropsychological profile of Becker Muscolar Dystrophy

Becker muscular dystrophy (BMD) is an heterogeneous neuromuscular disorder due to mutations in the DMD gene, characterized by progressive proximal muscles weakness, calf hypertrophy and cardiomyopathy. Different isoforms of the dystrophin are also expressed in cerebral cortex and Purkinje cells. Studies on Duchenne Muscular Dystrophy revealed lower scores in verbal intellective quotient (IQ), verbal working memory and verbal understanding abilities. Impairment in language, short term memory, reading, writing and executive functions has also been reported. Since now only few data about CNS involvement in BMD are available. We collected clinical history and sociological information and performed extensive neuropsychological assessments on 28 male BMD patients with age from 18 to 65 years old, ambulant and without a relevant cardiomyopathy. Most of the patients carried a deletion of exons 45-47. Cognitive aspects analysed included attention and executive function, deductive reasoning, language, memory, praxis and pre-frontal functions. None of the patients showed intellectual deficiency. Significant abnormalities were detected mainly with the Dual Task (11/28) and PASAT (6/28) tests. Borderline scores have also been reported in the Recurrent Faces (1 pathological, 10 borderline), Inverse Digit Span (1 pathologic, 8 borderline) and Inverse Corsi Span (3 pathologic, 3 borderline) tests. Despite cognitive abnormalities in DMD subjects have been described in literature, little is known about a comprehensive cognitive profile in BMD patients. In this study, the pattern of cognitive impairment points toward a defect in working memory in the BMD population. This data need confirmation with further evaluation in a wider and genetically heterogeneous population.