Neurological and pharmacological evaluation of a case of stiff-man syndrome.

A typical case of stiff-man syndrome was studied neurophysiologically and pharmacologically focusing the attention on a central disorder, either spinal or suprasegmental. The results support the hypothesis that a gamma type of hypertonia is one of the causes of the stiff-man syndrome, ruling out the participation of the Renshaw circuits. The syndrome should be considered a central disorder of the descending pathways that control and modify gamma activity and the startle reaction mechanisms, especially affecting the circuits that use Gabaergic mediators.