Improving paralyzed hand and finger function is a major rehabilitation goal for stroke patients, but many patients exhibit poor movement due to sensory impairment despite mild motor paralysis.

　Therefore, in this study, in order to explore how sensory feedback affects object grasping movements with fingers, we first aimed to understand the characteristics of stroke patients' object grasping movements: (1) force adjustment according to the weight of the object, and (2) movement stability. and (3) predictive control. As a result, they found that when stroke patients grasp objects, the affected side (1) exerts significantly excessive grasping force, (2) has poor object grasping stability, and (3) stagnates predictive control on the affected side compared to the healthy side. .

　Additionally, these characteristics are more closely related to sensory impairment than to motor paralysis; the more severe the sensory impairment, the more likely it is that excessive grip force will be produced, the stability of grasping the object will be lost, and predictive control will be impaired. It was suggested.

　Sensory information is essential not only for sequential feedback control of motor movements, but also for ``updating internal models,'' which utilizes error information obtained as a result of movement for the next movement. Therefore, it is possible that long-term sensory impairment prevents the internal model from updating and makes it difficult to control the grip force predictively, leading to excessive output and clumsiness in these cases.

　This research group is considering rehabilitation that can improve hand and finger function in stroke patients who exhibit poor movement due to sensory impairment, and will also proceed with research to verify its effectiveness using grip force measurement.

Paper information:【Clinical neurophysiology】Relative contribution of sensory and motor deficits on grip force control in patients with chronic stroke