Effect of stimulus parameters on characteristics of the F-response in normal subjects.
The F-response is a valuable tool for evaluating the functional integrity of proximal nerve segments. Although many studies have focused on the various F-response characteristics observed (e.g., latency, amplitude, duration, persistence, etc.), few have examined the significance of stimulus parameters on the resultant F-response. In this study, we examined the F-responses obtained in 25 healthy subjects when using various stimulus parameters. The stimulus parameters used were: 1) 0.5 Hz, 25% supramaximal intensity at 0.05 ms duration; 2) 0.5 Hz, 25% supramaximal intensity at 0.1 ms duration; 3) 0.5 Hz, 25% supramaximal intensity at 0.2 ms duration; 4) 0.5 Hz, 50% supramaximal intensity at 0.1 ms duration; 5) 3.0 Hz, 25% supramaximal intensity at 0.1 ms duration. No significant differences in F-response latency, amplitude, duration or persistence were seen when duration or intensity of stimuli was altered. However, changing stimulus frequency resulted in a significant decrease in latency and a significant increase in persistence and amplitude. Care should be taken in controlling for stimulus frequency to enhance the reproducibility of F-response determinations.
Clinchot
D M
DM
Department of Physical Medicine and Rehabilitation, Ohio State University, College of Medicine, Columbus 43210.
Colachis
S C
SC
Kaplansky
B D
BD
Mysiw
W J
WJ
D000328:Adult; D000704:Analysis of Variance; D004558:Electric Stimulation / Q000379:methods*; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008475:Median Nerve / Q000502:physiology*; D008875:Middle Aged; D009431:Neural Conduction / Q000502:physiology*; D011826:Radial Nerve / Q000502:physiology*; D011930:Reaction Time; D015203:Reproducibility of Results