Nerve conduction studies in Guillain-Barré syndrome: Influence of timing and value of repeated measurements

•Clinical severity but not timing of NCS correlates with fulfilling the electrophysiological criteria in GBS.•Repeated NCS increases the rate of successful electrophysiological classifications of either demyelinating or axonal GBS subtype.•A change in GBS subtype classification between the initial and follow-up studies can occur in a minority of patients.•Reversible conduction failure was found in 7% of patients.