Unveiling a Regional Variant of Demyelinating Guillain–Barré Syndrome: Nerve Conduction Study Evidence in Bifacial Weakness With Paresthesias

Background and Aims Guillain–Barré syndrome (GBS) is categorized into acute inflammatory demyelinating polyneuropathy (AIDP) and axonal GBS. Bifacial weakness with paresthesias (BFP) is regarded as a rare regional variant of AIDP, yet its electrophysiological characteristics remain inadequately defined. This study aimed to clarify the pathophysiological basis of BFP and its classification under AIDP through serial nerve conduction study (NCS) analysis. Methods NCS data of six patients diagnosed with BFP were retrospectively analyzed. Four patients underwent serial NCSs, while two received a single NCSs. The electrophysiological criterion for AIDP diagnosis was applied to data from both single and serial studies. Results Five of the six patients were classified with AIDP. Among the two with a single NCS, one was classified with AIDP and another with equivocal. All four patients with serial NCSs ultimately met AIDP criteria, with three showing demyelination initially and one progressing from equivocal. Three showed temporal evolution of demyelinating features. Interpretation Our study demonstrates a demyelinating nature of BFP. Repeated NCS over time enhance the probability of identifying de‐ and re‐myelination process, characterizing the underlying pathophysiology of BFP patients.