[Electrophysiologic studies in Guillain-Barré syndrome]

A preliminary investigation into electrodiagnostic methods in healthy children and in children with the Guillain-Barré syndrome (polyradiculoneuritis) was carried out in order to assess the validity of these procedures in the management of the disease. Studies of the strength-duration curves, the rheobase, the chronaxyie, the accommodation index curves, motor nerve conduction and electromyography were made in 30 healthy children and in 15 children suffering from polyradiculoneuritis. The strength-duration curves plotted on the rectus femoris muscles of the 15 sick children showed a steeply rising hyperbola and no response was elicited at the shorter pulse durations (less than 0.3 ms). The chronaxyie was long in very clinically involved muscle. The accommodation index curve showed a notably decreased slope in the left gastrocnemius muscles of the 15 patients. Conduction velocity of the anterior tibial nerve was either absent or low in all the patients during the first month of the disease. Electromyographic records showed disappearance of the interference pattern on maximal contraction of the diseased muscles; only a few isolated motor units could be recorded in the first month of the disease. The duration and amplitude of these units was markedly reduced, there was an increase in infrequency of polyphasic potentials and the presence of fibrillation potentials was noted in some cases. Serial electrophysiological studies should therefore be of interest and of value in the management of polyradiculoneuritis.