F-waves in clinical neurophysiology: a review, methodological issues and overall value in peripheral neuropathies

This report comments on methodological issues related to the use of F-wave in clinical neurophysiology. An F-wave study aims to describe with relative accuracy the properties of the compound F-wave population which is the population of F-waves consecutively recorded from a muscle. This can only be achieved if an adequate number of F-waves is sampled. In order to avoid inaccuracies, correction of F-wave latency measurements for height or limb length and age is also required. Differences in the recording procedure could account for the variability in F-wave measurements. The usefulness of F-wave parameters other than latency is discussed. F-chronodispersion and F-tacheodispersion are more sensitive than conventional neurophysiological methods in detecting mild nerve lesions. F-persistence provides valuable information only if the findings are interpreted in correlation with the particular clinical setting. The suitability of the F-wave technique for routine studies is examined and a current view on the clinical applications is briefly recounted. There is an urgent need for the standardization of F-wave methodology.