Gait also requires balance and the roles of visual senses, vestibular system and somatosensory system are important to maintain postures. Also, Gait is a voluntary movement that requires interactions between sensory, muscular and central nerve systems.
Therefore, gait disorder may improve by using the external stimulus on sensory system. However, there have not been many studies on biomechanical changes of gait, a dynamic posture of body, when a somatosensory stimulation is applied.
As such, this study reviewed the effect of somatosensory stimulation on the muscles during gaits. A vibratory stimulus was used to stimulate somatosensory system. This study applied somatosensory stimulation on the Achilles and tibialis anterior tendons in elderly and young people and analyzed the change of ground reaction force to investigate break and drive force during stance phase and electromyogram (EMG) to investigate the activation of muscles involved in gaits.
The analysis results showed changes in the peak of ground reaction force and confirmed activated muscles through EMG, which represented that somatoensory stimulation affects the contraction of muscles and on the reaction force of the foot during the stance phase. We also confirmed the optimal spots and timing for stimulation to improve gait after synchronizing the ground reation force and gait cycle of EMG.
Using the results of the analysis, we realized a model that detects gait cycle and abnormal gait and applies proper somatosensory stimulation using a small 3-axis movement sensor.
Gait experiment was performed to validate this hardware in actual situation with 3-dimentional motion analysis and gait analysis.
The results showed changed ground reaction force and angle of joint, which was considered that local somatosensory stimulation gave immediate feedback and changed the characteristics of gait during the gait. The study used a real-time analysis of patient’s movement and external stimulation applied at proper timing and its results would be usefully applied in patients who requires gait guidance and have gait abnormality due to lack of balance for rehabilitation.