Electromyographic findings in multiple sclerosis: remitting signs of denervation

Twenty-nine patients with multiple sclerosis (MS) producing weakness or paralysis of lower and often upper extremities underwent electromyographic (EMG) examinations. Nineteen patients had no signs of neurogenic atrophy (NA) in involved limbs and normal motor nerve conduction velocities. In 4 patients signs of acute NA (fibrillations, positive waves) present on at least one examination of involved limbs disappeared on subsequent examination. Motor nerve conduction studies were normal. In 4 patients, signs of NA in lower extremities persisted for more than 1 year. In 2 patients, NA resulted from peripheral neuropathy. It is not uncommon for NA to occur in MS when muscle weakness or paralysis is present. Signs of NA apparently can remit as do other neurological signs in MS. Prospective EMG studies of MS patients are needed to document further any involvement of peripheral nervous system and the extent to which such signs can remit.