2020 Volume 41 Pages 45-53
Developing a new training method that improves the ability of motor control is useful for rehabilitation for patients and elderly people and children for motor skill training. In order to clarify whether the stochastic resonance leads to improvement of human motor function, this study examined the effect of the subthreshold electrical stimulation on the adjustment ability of gripping force. Using the device that quantitatively evaluates the ability of adjustment of gripping （iWakka）， the subjects performed a motor task to accurately match the hand grip force to the target value presented on the monitor. After performing the practice, the trial of presenting electrical stimulation under sensory threshold （0.9 times of the sensory threshold） to the median nerve （ON condition） and the trial without electrical stimulation （OFF condition） are randomly performed. The difference between the exerting gripping force and the target value was compared between both conditions. In the ON condition, the absolute error of the target value and the gripping force in the isometric and concentric contraction was significantly lower than that in the OFF condition. It is considered that the subthreshold electric stimulation activated the central nervous system and this phenomenon improved the ability controlling the finger movement. It is useful to apply the stochastic resonance for facilitation of human sensorimotor function.
