Voluntary contraction enhances spinal reciprocal inhibition induced by patterned electrical stimulation in patients with stroke

Article type: Research Article

Authors: Takahashi, Yoko^{a; b} | Fujiwara, Toshiyuki^{c; *} | Yamaguchi, Tomofumi^{a; d; e; f} | Matsunaga, Hikaru^b | Kawakami, Michiyuki^a | Honaga, Kaoru^{a; b} | Mizuno, Katsuhiro^a | Liu, Meigen^a

Affiliations: [a] Department of Rehabilitation Medicine, Keio University School of Medicine, Tokyo, Japan | [b] Tokyo Bay Rehabilitation Hospital, Chiba, Japan | [c] Department of Rehabilitation Medicine, Juntendo University Graduate School of Medicine, Tokyo, Japan | [d] Department of Physical Therapy, Yamagata Prefectural University of Health Sciences, Yamagata, Japan | [e] JSPS Overseas Research Fellow | [f] Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark

Correspondence: [*] Corresponding author: Toshiyuki Fujiwara, MD, Ph.D., Professor and Chairperson, Department of Rehabilitation Medicine, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421 Japan. Tel.: +81 3 3813 3111; Fax: +81 3 5684 1861; E-mail: tofuji@xc5.so-net.ne.jp.

Abstract: Background:Reciprocal inhibition (RI) may be important for recovering locomotion after stroke. Patterned electrical stimulation (PES) can modulate RI in a manner that could be enhanced by voluntary muscle contraction (VC). Objective:To investigate whether VC enhances the PES-induced spinal RI in patients with stroke. Methods:Twelve patients with chronic stroke underwent three 20 min tasks, each on different days: (1) PES (10 pulses, 100 Hz every 2 s) applied to the common peroneal nerve; (2) VC consisting of isometric contraction of the affected-side tibialis anterior muscle; (3) PES combined with VC (PES + VC). RI from the tibialis anterior to the soleus muscle was assessed before, immediately after, and 10, 20, and 30 min after the task. Results:Compared to the baseline, PES + VC significantly increased the changes in reciprocal inhibition at immediately after and 10 min after the task. PES alone significantly increased this change immediately after the task, while VC alone showed no significant increase. Conclusion:VC enhanced the PES-induced plastic changes in RI in patients with stroke. This effect can potentially increase the success rate of newer neurorehabilitative approaches in achieving functional recovery after stroke.

Keywords: H-reflex, spinal plasticity, electrical stimulation, spasticity, hemiplegia, locomotion

DOI: 10.3233/RNN-170759

Journal: Restorative Neurology and Neuroscience, vol. 36, no. 1, pp. 99-105, 2018