Effect of gaze-stabilization exercises on vestibular function during postural control

Abstract

Gaze-stabilization exercise (GSE) is often conducted in vestibular rehabilitation, but its effect on vestibular function in postural control is not clear. We investigated whether GSE affects vestibular function during static upright standing and vestibulospinal reflex (VSR) in healthy young adults. First, the center of pressure of the total trajectory length (CoP-L) was measured before each GSE task or control (only standing) task (pre), immediately after (post), and 10 min after (post10) in the static standing position on foam rubber with the eyes open or closed (EC). Second, the H-reflex on the soleus muscle was measured after the onset of ipsilateral anodal galvanic vestibular stimulation before and after a GSE or a control task to estimate the amount of VSR induced by electrical vestibular input. CoP-L for the pre, post, and post10 control tasks and the GSE in EC did not differ significantly; the CoP-L for the post and post10 tasks in EC were significantly lower than that for the pretask. The H-reflex was inhibited by galvanic vestibular stimulation in the pre-GSE tasks. The inhibition increased after GSE, but not during control tasks. These findings suggest that GSE immediately improves the postural stability required for vestibular function and can be mediated by VSR improvements.

Gaze stabilization exercises derive sensory reweighting of vestibular for postural control

“…In this study, the CoP-L values on foam rubber with EO and EC were significantly decreased after GSE. This finding is consistent with a previous study wherein GSE improved the balance function during upright standing on foam rubber 8 ) . The foam rubber can make the somatosensory input from peripheral of lower limb unreliable 1 ) , thus the usable sensory is visual and vestibular during standing on foam rubber.…”

“…With regard to GSE, the upright standing subjects were instructed to repetitively rotate their heads to the right and left in accordance with a 2-Hz beeping sound for 1 min while gazing at a visual target placed in front, with the stipulation that the target remains in focus during the head movements 8 ) . The left and right rotation angles of the head were the largest when the subjects were able to gaze at the target.…”

“…The GSE is effective to improve not only gaze stability during head movement in patients with vestibular hypofunction 5 ) and in healthy young adults 6 ) , but also balance function in static and dynamic movements of healthy elderly people 7 ) . Furthermore, GSE recently improved the balance in a condition that required vestibular function 8 ) , and one of the mechanisms of this improvement is plastic change of vestibulospinal reflex for upright standing 8 ) . Therefore, GSE is a possible method to induce sensory contribution of the vestibular sensory system for upright static postural control, but it is unclear.…”

Vibration Applied to the Lateral Muscle of the Neck Induces Ipsilateral Body Sway during Sit-to-Stand Exercise in Healthy Adults – A Pilot Study

“…To induce the sensation that the body is swaying without actual movement, participants experienced illusory movements toward the direction at which the vibrated muscle would be stretched [6,7]. Vibration activates the muscle spindles and increases the firing rate of group Ia neurons in the muscle spindles [2][3]. The primary endings of the muscle spindles play an important role in the illusion of kinesthetics, because the primary endings are the most sensitive to muscle vibration [6,7].…”

“…Cognition consists of visual information [2], vestibular sensation [3,4], and somatosensory information [5]. Vibratory stimulation of the muscle activates the muscle spindle and increases the firing rate in ascending group Ia neurons, likely because of the stretching of the muscles [6,7].…”