Rare condition involving decay of motor anterior horn cells in the spinal cord, causing slack paralysis. There are forms that occur particularly in children and which are probably hereditary; the more severe form rapidly causes invalidity, the more benign form only causes a certain degree of invalidity in later life. Spinal muscular atrophy in adults usually begins between the ages of 40 and 60; the cause is still unknown. The symptoms are increasing slack paralysis, leading to muscular atrophy. Irritation of the motor anterior horn cells causes small muscular contractions (fascicula-tion). The condition can be a component of amyotrophic lateral sclerosis; it can deteriorate gradually and is poten- tially fatal if respiratory difficulties set in. Diagnosis is by the characteristic clinical picture and electrical tests of muscles. There is no specific treatment.
