A clinicophysiologic study of central and peripheral motor conduction in hereditary demyelinating motor and sensory neuropathy.

Central and peripheral motor nerve conduction were analyzed in 13 patients with hereditary demyelinating motor and sensory neuropathy using central magnetic stimulation and peripheral electrodiagnostic techniques. All patients showed a marked decrease in peripheral nerve conduction velocity. In 11 patients, the central motor conduction time was slightly prolonged but in 2 it was markedly prolonged suggesting dysfunction of the corticospinal tract. These two patients exhibited marked weakness and atrophy of distal muscles without clinical signs of upper motor neuron dysfunction, which was considered to be masked by the lower motor neuron disorder. This study suggests that in some patients with hereditary demyelinating polyneuropathy central as well as peripheral nerve fibers may be affected.