This study by Hadden et al. (1998) investigates the electrophysiological classification of Guillain-Barré Syndrome (GBS) and its clinical associations and outcomes. The study included 369 patients enrolled in a trial comparing plasma exchange, intravenous immunoglobulin, and both treatments. Patients were classified into five groups based on motor nerve conduction criteria: 69% were demyelinating, 3% axonal, 3% inexcitable, 2% normal, and 23% equivocal. Patients with axonal neurophysiology were more likely to have had a preceding diarrheal illness and to have antiganglioside GM1 antibodies. The group with initially inexcitable nerves had a higher proportion of patients who were unable to walk unaided at 48 weeks compared to other groups, but there was no significant difference between the axonal and demyelinating groups. The study also found that "pure motor GBS" patients, defined as those with normal sensory examination and sensory action potentials, were more likely to have axonal neurophysiology and preceding diarrhea. The outcomes of different treatments did not differ significantly among the electrophysiological subgroups or any neurophysiological category. The results suggest that the electrophysiological classification of GBS provides valuable insights into clinical features and outcomes, but further research is needed to understand the pathophysiology of axonal GBS.This study by Hadden et al. (1998) investigates the electrophysiological classification of Guillain-Barré Syndrome (GBS) and its clinical associations and outcomes. The study included 369 patients enrolled in a trial comparing plasma exchange, intravenous immunoglobulin, and both treatments. Patients were classified into five groups based on motor nerve conduction criteria: 69% were demyelinating, 3% axonal, 3% inexcitable, 2% normal, and 23% equivocal. Patients with axonal neurophysiology were more likely to have had a preceding diarrheal illness and to have antiganglioside GM1 antibodies. The group with initially inexcitable nerves had a higher proportion of patients who were unable to walk unaided at 48 weeks compared to other groups, but there was no significant difference between the axonal and demyelinating groups. The study also found that "pure motor GBS" patients, defined as those with normal sensory examination and sensory action potentials, were more likely to have axonal neurophysiology and preceding diarrhea. The outcomes of different treatments did not differ significantly among the electrophysiological subgroups or any neurophysiological category. The results suggest that the electrophysiological classification of GBS provides valuable insights into clinical features and outcomes, but further research is needed to understand the pathophysiology of axonal GBS.