Effect of motor imagery and voluntary muscle contraction on the F wave.
We tested the validity of instructing patients to minimally contract the muscle to facilitate F-wave recording in clinical practice. In 12 healthy subjects, F waves were recorded from the first dorsal interosseous muscle at rest, during motor imagery, and at up to 30% of the maximal voluntary contraction (MVC). F-wave persistence increased significantly from 32.5 +/- 11.9% (mean +/- SD) at rest to 58.3 +/- 15.2% during motor imagery and 90.0 +/- 8.7% during 3% MVC. It then remained the same during stepwise changes to and from 30% MVC before decreasing significantly from 80.8 +/- 18.5% during 3% MVC to 48.7 +/- 23.8% during motor imagery and 27.0 +/- 16.0% at rest. The trial average of F-wave amplitude showed a similar pattern of facilitation. Motor imagery enhances F-wave persistence and amplitude, which further increase with a slight muscle contraction and show no additional change with a stronger effort.
Hara
Motohiko
M
Department of Rehabilitation Medicine, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8606, Japan. motohiko@med.teikyo-u.ac.jp
Kimura
Jun
J
Walker
D David
DD
Taniguchi
Shinichirou
S
Ichikawa
Hiroo
H
Fujisawa
Reiko
R
Shimizu
Hiroshi
H
Abe
Tatsuya
T
Yamada
Thoru
T
Kayamori
Ryoji
R
Mizutani
Tomohiko
T
D000200:Action Potentials / Q000502:physiology*; D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D004558:Electric Stimulation; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000502:physiology; D005260:Female; D006801:Humans; D007092:Imagination / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009048:Motor Skills / Q000502:physiology; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*