[Amyotrophy of parietal origin: Silverstein's syndrome. Clinical and electrophysiologic study]

Clinical and electrophysiological data in two cases of amyotrophy of parietal origin (Silverstein's syndrome) are reported. Some parietal lesions provoke amyotrophy, usually with a sensory deficit but sometimes isolated, of rapid onset and affecting mainly the upper limb extremity. In the two cases reported, a spontaneous electromyographic activity was present with fibrillation and positive sharp waves, an unusual finding in central nervous system diseases. Despite its lack of specificity an activity of this type is observed mainly with peripheral axonal lesions. The physiopathology of Silverstein's syndrome is entirely hypothetical. The decreased transsynaptic trophic influence of central on peripheral cells could result in a reduced trophic effect of peripheral nerves on muscles, and the spontaneous activity could be related to muscle cell membrane instability.