" SICK " MOTONEURONES A Unifying Concept of Muscle Disease

New electrophysiological techniques have demonstrated a loss of motor units in muscular dystrophy and myasthenia gravis; the sizes of the surviving motor units suggest that both diseases result from disordered function of motoneurones. Estimates have been made of the incidence of healthy, sick, and dead motoneurones in these conditions and, for comparison, in recognised denervating processes such as motor-neurone disease and the Kugelberg-Welander syndrome.