Electrodiagnosis of reversible conduction failure in Guillain–Barré syndrome

ABSTRACT Introduction: In this study we propose electrodiagnostic criteria for early reversible conduction failure (ERCF) in axonal Guillain–Barré syndrome (GBS) and apply them to a cohort of GBS patients. Methods: Serial nerve conduction studies (NCS) were retrospectively analyzed in 82 GBS patients from 3 centers. The criteria for the presence of ERCF in a nerve were: (i) a 50% increase in amplitude of distal compound muscle action potentials or sensory nerve action potentials; or (ii) resolution of proximal motor conduction block with an accompanying decrease in distal latencies or compound muscle action potential duration or increase in conduction velocities. Results: Of 82 patients from 3 centers, 37 (45%) had ERCF, 21 (26%) had a contrasting evolution pattern, and 8 (10%) had both. Sixteen patients did not show an amplitude increase of at least 50%. Conclusion: Our proposed criteria identified a group of patients with a characteristic evolution of NCS abnormality that is consistent with ERCF. Muscle Nerve 56: 919–924, 2017