[Continuous muscular activity. Clinical aspects and neurophysiological differences from Isaacs' syndrome].

We report a case of continuous muscle activity, unusual from both the clinical and neurophysiological point of views. The neurological examination revealed a continuous rippling of muscles, but limited to the lower part of the face, to the forearm and to the muscles of the thenar eminence. All deep reflexes were normal. Hyperperspiration, spasms and stiffness of abnormal postures were absent. Electromyography displayed continuous motor unit discharges. An abnormal F wave was elicited only from the affected territories. The disappearances of the spontaneous activity and of the F wave occurred not only after the motor nerve block, but also after the block of the afferent sensitive fibres. Therapy with carbamazepine, hydantoin, diazepam and baclofen did not bring improvement.