Serial electrophysiology in Guillain‐Barré syndrome: A retrospective cohort and case‐by‐case multicentre analysis

Objectives To assess the usefulness of serial electrophysiology in Guillain‐Barré syndrome ( GBS ) in a multicenter setting and the reasons for change in electrodiagnostic subtypes with serial studies. Methods We retrospectively analysed serial electrophysiology of 51 patients with GBS from 4 European centres. Proportions of subtypes were determined at each timing. Individual case analyses were also performed where diagnostic changes occurred with either criteria, to ascertain if changes were due to disease progression or criteria inadequacy. Results At first study, comparing old vs new criteria, acute inflammatory demyelinating polyneuropathy ( AIDP ) was diagnosed in 70.6% vs 51%, axonal GBS in 15.7% vs 39.2%, equivocal forms in 11.8% vs 7.8%. At second study, AIDP was diagnosed in 72.5% vs 52.9%, axonal GBS in 9.8% vs 33.3%, equivocal forms in 15.7% vs 11.7%. Subtype proportions were unchanged, indicating serial studies did not, in the cohort, alter diagnostic rates for each subtype irrespective of criteria used. Individual review of cases where subtype electrodiagnosis changed indicated suboptimal specificity for AIDP /sensitivity for axonal GBS as main cause of diagnostic shifts with old criteria, whereas disease progression explained most changes with new criteria (55.6% vs 81.8%; P  = .039). Conclusions Serial electrophysiology is unhelpful in GBS . Repeat studies cannot represent the gold standard as electrodiagnosis may alter due to disease progression. Changes in electrodiagnosis relate more often to disease progression with new criteria but are more frequently due to suboptimal sensitivity/specificity with old criteria. A single electrophysiological study using the most accurate available criteria appears sufficient in GBS .