Effect of height on F-wave latency: Redefining reference values for Iranian population

Intrudaction: F-wave latency is one of the most sensitive parameters which is used for diagnosis of radiculopathy and neuropathy in electrodiagnostic medicine. Electrodianosis professionals mostly use reference values published in major textbooks mostly written in USA based on anthropomorphic characteristics of American people. Also there is considerable difference between heights of males and females in each country, which is not considered in reference tables. We performed this study to determine any difference between F-wave latencies in both genders and also between our population and mainly used reference values. Methods: This cross-sectional study was performed on 60 healthy volunteers (30 males and 30 females). Minimum F-wave latencies of median and ulnar nerves at wrist, and also tibial and peroneal nerves at ankle were recoded after ten supramaximal stimulation of each nerve. Results: The average heights were 156.05±4.80 and 171.58±6.05 centimeters in females and males, respectively. Mean of minimum F-wave latencies in males were 24.93±1.55, 25.73±1.48, 46.86±2.94 and 46.91±3.04 and in females were 22.66±1.23, 22.97±1.33, 42.61±3.20 and 42.33±3.17 milliseconds for median, ulnar, tibial and peroneal nerves, respectively. These values were significantly higher in males than females. There was correlation between height and mean of F-wave latencies in median, ulnar, tibial and peroneal nerves. There were significant differences between males and females in all tested nerves. Also there were significant differences between our measured latencies and the reference values published in major electrodiagnostic textbooks. Conclusion: Regarding the significant height difference between two genders, we recommend defining separate reference values for each group. On the other hand, each population should have its own reference values corresponding to average height of its own people otherwise the sensitivity of this parameter (F-wave latency) will be significantly low.