A new method using F-waves to measure muscle fiber conduction velocity (MFCV).
OBJECTIVE
First, to propose a new technique for measuring muscle fiber conduction velocity (MFCV). Second, to ascertain the validation of the new method that uses F-waves (F-MFCV) in healthy volunteers. Third, to examine the relationship between F-MFCV and motor nerve conduction velocity (MCV) in the same subjects.


METHODS
F-waves reflecting single motor units were recorded with a multi-channel surface electrode array and weak electrical stimulation to the median or ulnar nerves in 21 healthy volunteers. F-MFCVs of the abductor pollicis brevis (APB) and abductor digiti minimi (ADM) were calculated from the F-wave peak latency in each channel. MFCV during minimal voluntary contraction (V-MFVC) was measured in the same muscles.


RESULTS
There was no significant difference between F-MFCV and V-MFCV in the muscles tested The mean F-MFCV value was similar to recently reported MFCV values generated by minimal voluntary contraction. No significant differences were found between the APB and ADM F-MFCVs, whereas the MCV of the ulnar nerve was faster than that of the median nerve.


CONCLUSIONS
The MFCV in a single motor unit could be measured with a multi-channel surface electrode array by recording F-waves induced by weak stimulation. Since V-MFCV generated by minimal voluntary contraction is explained by the size principle, V-MFCV reflects small and slow conducting motor unit. There was no significant difference between F-MFCV and V-MFCV. It seemed that F-MFCV also reflected small motor unit. The reason for the lack of difference in the F-MFCVs of the ADM and APB is considered to be a relatively slow F-MFCV. Moreover, MCV reflected the speed of the fastest nerve fiber, whereas F-MFCV did not.
Metani
H
H
Department of Rehabilitation Medicine, Kawasaki Medical School, Matsushima 577, Kurashiki-City, Okayama, 701-0192, Japan. metani@med.kawasaki-m.ac.jp
Tsubahara
A
A
Hiraoka
T
T
Aoyagi
Y
Y
Tanaka
Y
Y
D000200:Action Potentials / Q000502:physiology*; D000328:Adult; D004576:Electromyography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008475:Median Nerve / Q000502:physiology; D009046:Motor Neurons / Q000502:physiology*; D009119:Muscle Contraction / Q000502:physiology; D018485:Muscle Fibers, Skeletal / Q000502:physiology*; D018482:Muscle, Skeletal / Q000166:cytology / Q000294:innervation / Q000502:physiology*; D014459:Ulnar Nerve / Q000502:physiology