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Prognostic Value of “A” Waves in Patients With Guillain Barre Syndrome

Badry, Reda

Journal of Clinical Neurophysiology: September 2019 - Volume 36 - Issue 5 - p 385–388
doi: 10.1097/WNP.0000000000000592
Original Research

Introduction: The “A” wave is a compound action potential evoked consistently from a muscle by submaximal electric stimulation to the nerve. “A” waves were usually associated with the presence of conduction block and abounded in lower limbs more than in upper limbs. Guillain Barre syndrome is an autoimmune polyradiculoneuropathy that usually follows respiratory or gastrointestinal infections.

Purpose: To study the prognostic value of “A” waves in patients with Guillain Barre syndrome with different recovery patterns.

Methods: In this study, 50 patients with GuillainBarreSyndrome were enrolled. They were divided into two groups based on the presence or absence of “A” waves in their neurophysiologic study at onset of illness. Strength of limb muscles of the involved patients was assessed at onset of the study and 6 weeks later (short-term clinical recovery) using the Medical Research Council Scale.

Results: Patients with waves (29 patients: 58%) showed poorer short-term follow-up parameters than those without “A” waves (21 patients: 42%).

Conclusions: Presence of “A” waves is usually associated with conduction block and marked degree of demyelination. “A” waves carry poor prognostic value in short-term follow-up parameters in patients with Guillain Barre syndrome.

Department of Neurology and Psychiatry, Assiut University Hospital, Assiut, Egypt.

Address correspondence and reprint requests to Reda Badry, MD, Department of Neurology and Psychiatry, Assiut University Hospital, Post Box 711526, Assiut, Egypt; e-mail:

The authors have no funding or conflicts of interest to disclose.

The data that support the findings of this study are available on request from the corresponding author (R. Badry). The data are not publicly available due to some institutional considerations.

© 2019 by the American Clinical Neurophysiology Society