These include impaired intellectual development and problems with the joints, the spine, the heart and the function of the lungs. Intellectual handicap is more frequent in boys with DMD than in the general population but only affects a minority. Unlike the muscle weakness, it is not progressive. Whatever intelligence an affected boy has at birth, he retains it unless it is affected by something else. 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 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 contractures.