Intellect and behaviour in Duchenne muscular dystrophy.

A study was made of intellectual, educational and emotional functioning of 57 boys with Duchenne muscular dystrophy, aged between three and 13 years, using standard intelligence tests, a reading test and the Rutter Behaviour Questionnaires. Their intelligence test scores were about 1 SD below the mean, the majority functioning better on performance than on verbal tasks. Reading levels were variable, but averaged about 1-5 SD below the mean; a large proportion of the boys read at a very low level. Both of the Behaviour Questionnaires showed a high rate of emotional disorder. The cognitive tests showed no change with age and the general pattern of functioning remained constant. This study confirms the view that intellectual impairment, and particularly verbal impairment, is associated with Duchenne muscular dystrophy, but it is non-progressive and does not affect all children. A high rate of emotional disturbance is also associated with the disease.