Suprathreshold mechanical vestibular stimulation affects postural control during standing
Advisor Information
Nicholas Stergiou
Location
Milo Bail Student Center Ballroom
Presentation Type
Poster
Start Date
8-3-2013 9:00 AM
End Date
8-3-2013 12:00 PM
Abstract
Successful postural control requires integrated information from visual, vestibular and somatosensory systems. While the contributions of visual and somatosensory contributions are easier to study because of the ease of perturbing these systems, this is not the case for the vestibular system. Conventional methods of perturbing the vestibular system are uncomfortable or painful. Therefore, to improve our understanding of the vestibular contributions to standing postural control, we used suprathreshold mechanical vestibular stimulation (sMVS) over the mastoid process. Our objective in this study was to determine the effect of sMVS on the maintenance of static standing posture in a perturbed environment. Six subjects were tested for their postural control through the Sensory Organization Test (SOT) with and without sMVS on the mastoid processes of both sides. The six SOT conditions were randomly presented to the participants. Postural control was measured by the performance index (PI). The PI is calculated by integrating rectified anterior-posterior (AP) sway signal, and then scaling the result as percentage of maximum AP sway during standing. Higher performance index values represented worse postural control and vice versa. The PI significantly increased (p = 0.027) in eye-closed, and unreliable somatosensory inputs condition from 8.56±2.52 (without sMVS) to 13.37±2.39 (with sMVS). The addition of the sMVS worsened the postural control during static standing by about 60%. These results are comparable to the SOT values obtained in subjects with acute vestibulopathy.
Suprathreshold mechanical vestibular stimulation affects postural control during standing
Milo Bail Student Center Ballroom
Successful postural control requires integrated information from visual, vestibular and somatosensory systems. While the contributions of visual and somatosensory contributions are easier to study because of the ease of perturbing these systems, this is not the case for the vestibular system. Conventional methods of perturbing the vestibular system are uncomfortable or painful. Therefore, to improve our understanding of the vestibular contributions to standing postural control, we used suprathreshold mechanical vestibular stimulation (sMVS) over the mastoid process. Our objective in this study was to determine the effect of sMVS on the maintenance of static standing posture in a perturbed environment. Six subjects were tested for their postural control through the Sensory Organization Test (SOT) with and without sMVS on the mastoid processes of both sides. The six SOT conditions were randomly presented to the participants. Postural control was measured by the performance index (PI). The PI is calculated by integrating rectified anterior-posterior (AP) sway signal, and then scaling the result as percentage of maximum AP sway during standing. Higher performance index values represented worse postural control and vice versa. The PI significantly increased (p = 0.027) in eye-closed, and unreliable somatosensory inputs condition from 8.56±2.52 (without sMVS) to 13.37±2.39 (with sMVS). The addition of the sMVS worsened the postural control during static standing by about 60%. These results are comparable to the SOT values obtained in subjects with acute vestibulopathy.