These include impaired intellectual development and problems with joints, the spine, the heart and the lungs. Intellectual handicap is more frequent in boys with DMD than in the general population but only affects a proportion of boys. Unlike the muscle weakness, it is not progressive. Whatever intelligence an affected boy has at birth, he retains it. This is so whether he is born with superior, average or less than average intelligence.
Joints tend to become restricted in their range of movements.
This is called joint contracture. The ankles are usually affected early, then the hips and knees and lastly the joints of the upper limbs. Physiotherapy and occupational therapy are directed against this complication. The physiotherapist advises on exercises to stretch the joints and the occupational therapist on good and bad sitting positions and activities. Surgery is sometimes used to correct joint contractures.