Some patients with Miller Fisher syndrome (MFS) have a severe tetraparesis such as that observed in Guillain--Barré syndrome (GBS). To determine whether pathophysiologic differences exist between the tetraparesis in MFS and that in GBS, we compared clinical and motor conduction findings in 4 MFS patients who developed severe tetraparesis with those in 5 MFS patients without tetraparesis, and 14 GBS patients. MFS patients with or without tetraplegia had normal motor conduction velocities, distal motor latencies, compound muscle action potential (CMAP) amplitudes, and F-wave latencies. CMAP amplitude tended to be lower in tetraparetic MFS patients than in MFS patients without tetraparesis, but not significantly. F-wave occurrence was slightly reduced in 1 MFS patient with tetraparesis and 1 MFS patient without tetraparesis. Motor conduction parameters were abnormal in 13 of 14 patients with GBS, and showed demyelinating features in 10. Our results suggest that the pathophysiology of tetraparesis in MFS differs from that in GBS.
Copyright 2002 Wiley Periodicals, Inc.