The efficacy of neuromuscular electrical stimulation with alternating currents in the kilohertz frequency to stimulate gait rhythm in rats following spinal cord injury.
BACKGROUND
Rehabilitation facilitates the reorganization of residual/regenerated neural pathways and is key in improving motor function following spinal cord injury. Neuromuscular electrical stimulation (NMES) has been reported as being clinically effective. Although it can be used after the acute phase post-injury, the optimal stimulation conditions to improve motor function remain unclear. In this paper, we examined the effectiveness of NMES with alternating currents in the kilohertz (kHz) frequency in gait rhythm stimulation therapy.


METHODS
Tests were performed using 20 mature female Fischer rats. Incomplete spinal cord injuries (T9 level) were made with an IH impactor using a force of 150 kdyn, and NMES was administered for 3 days from the 7th day post-injury. The needle electrodes were inserted percutaneously near the motor point of each muscle in conscious rats, and each muscle on the left and right leg was stimulated for 15 min at two frequencies, 75 Hz and 8 kHz, to induce a gait rhythm. Motor function was evaluated using Basso, Beattie, Bresnahan (BBB) scores and three-dimensional (3D) gait analysis. Rats were divided into four groups (5 rats/group), including the NMES treatment 75-Hz group (iSCI-NMES 75 Hz), 8-kHz group (iSCI-NMES 8 kHz), injury control group (iSCI-NT), and normal group (Normal-CT), and were compared.


RESULTS
There was no significant difference in BBB scores among the three groups. In 3D gait analysis, compared with the injury control group, the 8-kHz group showed a significant improvement in synergistic movement of both hindlimbs.


CONCLUSIONS
We suggest that kHz stimulation is effective in gait rhythm stimulation using NMES.
Department of Orthopedic Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, 755-8505, Japan. tkanchik@yamaguchi-u.ac.jp.
Tsukasa
T
Kanchiku
Department of Orthopedic Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, 755-8505, Japan. hsuzuki@yamaguchi-u.ac.jp.
Hidenori
H
Suzuki
Department of Orthopedic Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, 755-8505, Japan. i-yasuak@yamaguchi-u.ac.jp.
Yasuaki
Y
Imajo
Department of Orthopedic Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, 755-8505, Japan. yuichinisan@nifty.com.
Yuichiro
Y
Yoshida
Department of Orthopedic Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, 755-8505, Japan. moriya103@yahoo.co.jp.
Atsushi
A
Moriya
Department of Orthopedic Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, 755-8505, Japan. ysuetomi@yamaguchi-u.ac.jp.
Yutaka
Y
Suetomi
Department of Orthopedic Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, 755-8505, Japan. sggk33nori@yahoo.co.jp.
Norihiro
N
Nishida
Department of Orthopedic Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, 755-8505, Japan. pontamasato624@yahoo.co.jp.
Youhei
Y
Takahashi
Department of Orthopedic Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, 755-8505, Japan. ttaguchi@yamaguchi-u.ac.jp.
Toshihiko
T
Taguchi
D000818:Animals; D000843:Ankle Joint / Q000503:physiopathology; D001696:Biomechanical Phenomena; D004553:Electric Conductivity; D004599:Electric Stimulation Therapy / Q000379:methods*; D005260:Female; D005684:Gait / Q000502:physiology*; D009043:Motor Activity / Q000502:physiology; D009119:Muscle Contraction / Q000502:physiology; D051381:Rats; D013119:Spinal Cord Injuries / Q000503:physiopathology* / Q000628:therapy*