Functional Changes On Peripheral Nerves Of Multiple Sclerosis: Electrophysiological Evaluation

Objective: To study the functional changes on peripheral nerves of multiple sclerosis (MS) patients, and to evaluate the value of the clinical electroneurophysiology techniques applied in this study. Methods: By using of nerve conduction velocity (NCV) technique, motor conduction velocity (MCV), sensory conduction velocity (SCV), latency and amplitude of the median, ulnar, tibial and peroneal nerves on both sides of limbs were examined; by using of motor evoked potential (MEP), latency elicited from different sites of the median and tibial nerves on both sides of limbs were examined; by using of F-wave, the percentage of responses and conduction velocity in the median nerves on both sides of limbs were examined. Results: MCV and SCV on the median, ulnar, tibial and "peroneal nerves of MS patients are slowly in different degree; the abnormality percentage of MCV is more than one of SCV; there are 48.5% of the patients have slow NCV that occurred in one nerve at least. The MCV prolonged latency mainly occurred in the distal segment of the median and ulnar nerves and in the proximal segment of the tibial and peroneal nerves. The NCV results indicate demyelination and axonal damages of MS peripheral nerves, and the latter is more significant. The MEP prolonged latency of elbow and L4 sites indicates injuries in the distal segment of the median nerve and in lumbar and sacral roots. The decreased percentages of F-wave responses indicate peripheral radiculopathy in some patients. Conclusion: There are functional changes on peripheral nerves of MS patients and consequentially abnormal results of the electrophysiological examination. It is sound to evaluate the function on peripheral nerves of MS by using combined different examination techniques of clinical electroneurophysiology.