F-wave amplitude.

To determine the diagnostic efficacy of F-wave amplitude and F/M-ratio measurements in routine electrodiagnostic examinations, normal values were established for the ulnar nerve and systematically applied to a group of patients with various nosological entities (Mononeuropathies at the elbow, radiculopathies of C8, polyneuropathies, anterior horn cell disorders, plexopathies, syringomyelias, others). As a result, F/M-ratio can distinguish between the various pathological conditions (P = 0.02). Patients with radiculopathy and accompanying myelopathy were identified by increased F/M-ratio. It is concluded that F-wave amplitude analysis can give hints for additional central pathology in the individual case.