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Rotation testing was performed to evaluate the functions of the vestibular system by applying a rotational stimulation to a subject and observing the eye movements caused by the vestibulo-ocular reflexes (VORs). VORs comprise the semicircular-ocular reflex (ScOR) and the otolith-ocular reflex (OOR). When the subject's lateral semicircular canal is positioned horizontal to the ground and earth vertical axis rotation (EVAR) is applied, the lateral semicircular canal is stimulated by rotational acceleration, resulting in eye movements caused by the ScOR. In contrast, with off-vertical axis rotation (OVAR), the direction of gravitational acceleration changes continuously during rotation, which simultaneously stimulates the otolith organ. The resultant eye movements are caused by both the ScOR and the OOR. In previous studies, the application of conflicting visual vestibular stimulation using a flat screen under EVAR conditions did not show a significant change in the VOR gain after stimulation. In the present study, we applied conflicting visual vestibular stimulation (1 stimulation, 2 stimulation) using a flat screen under OVAR conditions and compared the VOR gain before and after stimulation. No significant change in the VOR gain was observed before and after 2 stimulation; however, a significant decrease in the VOR gain was observed after 1 stimulation. These results were obtained due to the effects of tilt suppression and because the conflicting visual vestibular stimulation we used was an appropriate form of stimulation to elicit the OOR. While various methods of vestibular rehabilitation have been reported for equilibrium disturbances, the effects of tilt suppression and whether the stimulation used for vestibular rehabilitation is an appropriate form of stimulation need to be considered. off-vertical axis rotation OVAR Effects of visual stimulation using a flat screen under off-vertical axis rotation conditions on the semicircular ocular reflex

Japan has become a super-aging society, and the number of elderly persons with dizziness is increasing. In addition, elderly persons with dizziness have a high risk of falling, and fractures caused by falls can decrease the life span. It is therefore necessary to take appropriate countermeasures. Treatments for dizziness are wide-ranging and include physical therapy, such as canalith repositioning, and pharmacotherapy. However, many patients do not improve even after these treatments. In this study, we compared the results of stabilometry examined before and after the use of a cane in 21 patients aged 65 years or older with a history of dizziness who visited our department (DHI score of 28 points or higher). The use of a cane improved the following measured parameters: total length of body sway, area of body sway, and unit area body sway length at the time of eye opening and closing. To prevent falling, somatic sense input and skeletal muscle input focused on the lower extremities are important. It is expected that these inputs decline in elderly persons, and based on the results of the current study, it is likely that the use of prosthetics, such as a cane, will play an important role in the future in supporting these subjects.

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