Dynamic F waves in neurogenic claudication

Abstract

Serial F waves were elicited before and after ambulation in 2 patients with neurogenic claudication. In both patients dynamic changes in F wave parameters consisting of either unelicitability or increased latencies occurred postexercise. The time course of these changes and their subsequent rapid reversibility over 15 minutes suggest ischemic-induced conduction block and slowing in proximal motor axons. These physiological changes may account for some of the dynamic neurological symptoms of this disorder. Moreover, F wave exercise testing may provide corroborative information for the diagnosis of neurogenic claudication.

Diagnostic validity of somatosensory evoked potentials in subgroups of patients with sciatica

“…Retraction of a nerve root during surgery causes increased P1 latency, which promptly returns to baseline after release of the retraction [33], and dynamic F-wave studies in neurogenic claudication show increased postexercise latencies [41]. Thus the nerve root conduction may change rapidly, consistent with the present findings, which indicates that the conduction disturbance is more pronounced, and the true-positive rate of SEP higher, when sciatic sensory symptoms are present during registration than when they are absent.…”

Motor conduction alterations in patients with lumbar spinal stenosis following the onset of neurogenic claudication

“…London and England [20] studied the effect of claudication on the F-wave and reported an increase in F-wave latency time in two cases they isolated. Manganotti et al [22] performed a similar study and reported similar observations in three of five patients tested.…”

Lumbar spinal stenosis: Assessment of cauda equina involvement by electrophysiological recordings

“…Electrophysiological recordings have also been applied during treadmill-or walking-stress tests to increase the diagnostic sensitivity in less symptomatic LSS patients [16,33,34,39,44]. In patients with mild LSS, electrophysiological recordings were pathological in an exercise treadmill test, but this was the case in patients both with and without neurogenic claudication [2].…”