Presence of repeater F‐waves in the early stage of Guillain‐Barré syndrome
The absence or a prolonged latency of late responses, like F‐waves, is a common neurophysiological finding with diagnostic utility in the early Guillain‐Barré syndrome. However, the presence and the number of repeater F‐waves have not been studied in this disease. In four patients, we report the transient presence of repeater F‐waves in nerves of the lower limbs shortly after the onset of the disease. In each patient, the initial (diagnostic) nerve conduction study showed a high incidence of repeater F‐waves in the tibial or in the peroneal nerves of one side, with normal distal motor latencies; in the other nerves explored the F‐waves were fully abolished and the motor potentials were abnormal. In a second study, done 2–6 weeks later, we observed the abolition of the F‐waves or a significant increase of its minimal latency in those nerves in which we had detected the repeaters. The presence of a high number of repeater F‐waves with normal latencies in some nerves may be a transient and initial electrophysiological sign useful in the early diagnosis of this disease.
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Document Type: Research Article
Publication date: March 1, 2012