2021 Fiscal Year Final Research Report

A new method for reducing hand spasticity using homeostasis of somatosensory system

Research Project

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Project/Area Number	19K22833
Research Category	Grant-in-Aid for Challenging Research (Exploratory)
Allocation Type	Multi-year Fund
Review Section	Medium-sized Section 59:Sports sciences, physical education, health sciences, and related fields
Research Institution	National Institute of Information and Communications Technology
Principal Investigator	Naito Eiichi 国立研究開発法人情報通信研究機構, 未来ICT研究所脳情報通信融合研究センター脳情報通信融合研究室, 室長 (10283293)
Project Period (FY)	2019-06-28 – 2022-03-31
Keywords	振動刺激 / 視覚-体性感覚痙縮軽減装置 / 皮質脊髄路興奮性 / 筋電図 / ニューロリハビリテーション / 運動イメージ / 経頭蓋磁気刺激
Outline of Final Research Achievements	There is clinical evidence that vibration stimulation of the palm of the hand at about 100 Hz can reduce hand spasticity (stiffness of hand muscles). When investigating this neural mechanism, we found muscle activity in the hand extensor muscle. The activity of the extensor muscle is directed toward reducing hand clasping spasticity, suggesting that this effect may be involved in the reduction of spasticity. In addition, a visual-somatosensory spasticity reduction device was developed that simultaneously provides a visual image of hand movements while receiving vibration stimulation to the palm of the hand. The excitability of corticospinal tracts was increased when hand movements were simultaneously observed while receiving the vibration stimulation and motor imagery of hand movements was further given in conjunction with these visual images. The effect of vibration stimulation was further enhanced by the addition of visual images and motor imagery of hand movements.
Free Research Field	神経科学
Academic Significance and Societal Importance of the Research Achievements	100Hz程度での手のひらへの振動刺激は手の痙縮(手の握りこみ)を軽減できるという臨床的知見があるが、その神経メカニズムは不明であった。本研究では、この刺激中に手の総指伸筋から筋活動が計測できることを初めて示した。総指伸筋の活動は手指を握りこむ痙縮を軽減する方向への作用であり、このような効果が痙縮軽減効果に関わっている可能性が示唆された。さらに、手のひらに振動刺激を受けながら、同時に手の動きの視覚映像を見る視覚-体性感覚痙縮軽減装置を開発した。この装置を使って、手の動きの視覚映像と運動イメージを組み合わせることで、振動刺激の効果はより増強できる可能性を示した。