Cognitive and personality function in myotonic muscular dystrophy.

Twenty-nine patients with myotonic dystrophy from 14 families were tested with the Wechsler and Shipley measures of cognitive function. Forty-one per cent of the subjects had little or no physical handicap. Approximately one-third had low Wechsler scores, whereas 7% had relatively high scores. There was a trend for affected females to have poorer cognitive function than males. Limited cognitive ability correlated with maternal inheritance of the gene and severe physical handicap, but there were individual exceptions. Strongest cognitive abilities were verbal and informational, whereas the weakest were immediate recall, abstraction and spatial manipulation and orientation. There was no evidence of intellectual decline with time. Signs of cerebral atrophy on CT scans were uncommon, occurring for certain in only one of 19 subjects. Personality profiles were also constructed for 25 myotonic subjects using interview and MMPI techniques. Forty-four per cent of the subjects had unremarkable personality profiles, 24% had mild personality difficulties and 32% had prominent personality abnormalities. Serious personality difficulty was most common in patients with low cognitive ability and advanced physical handicap. There was no "typical" personality pattern representative of the entire group. It is likely that many personality problems were the result of individuals with limited resources attempting to cope with their physically deforming and debilitating neuromuscular disorder.