The localization of the lesion in patients with acute ophthalmoplegia, ataxia and areflexia (Miller Fisher syndrome). A serial multimodal neurophysiological study.

Results of comprehensive serial neurophysiological tests from onset to full recovery in 3 patients with the Miller Fisher syndrome (acute ophthalmoplegia, ataxia and areflexia) are presented. These included EMG and nerve conduction, late response (H and F wave) and direct facial motor and blink reflex studies, computerized motor unit number estimation, automated quantitative sensory threshold measurements, quantitative pupillometric and pupillopharmacological studies and multimodality evoked potential (VEP, SEP and BAEP) and EEG recordings. The results provided unequivocal evidence of peripheral nerve dysfunction. Improvement of the peripheral neurophysiological parameters accompanied or followed clinical recovery in all 3 patients. No abnormality in the CNS pathways investigated by these tests was found. The findings support the conclusion that this syndrome is to be included within the spectrum of acute inflammatory polyneuropathy. The value of serial measurements in detecting milder peripheral nerve lesions is emphasized.