The following article has just been accepted for publication in Journal of Neurologic Physical Therapy:
“Gripping an External Object Stabilizes Upright Posture Perturbed by a Moving Virtual Environment in Patients with Traumatic Brain Injury”
Ksenia Ustinova, PhD; Deborah Silkwood-Sherer
BACKGROUND AND PURPOSE: Gripping an external mobile (unfixed) object while standing increases postural stability in healthy individuals. The purpose of this study was to test whether the same strategy is effective for stabilizing upright posture perturbed by a moving environment in patients with Traumatic Brain Injury (TBI).
METHODS: Fifteen individuals with mild-to-moderate postural and coordination deficits after TBI and 15 age-matched healthy subjects participated in the study. Participants stood for 1 minute in front of an 82-inch screen, with a projected 3D image of a boat. The boat remained stationary for 30 seconds, and rocked on water at a speed of 15º/s (producing visual stimulation), for the other 30 seconds of each 1-minute trial. Visual stimulation was applied during either the first or second half of the trial, determined pseudo-randomly. To analyze postural stability, the displacement and velocity of the Center of Mass (COM) in the sagittal and frontal planes were compared between groups and across four experimental conditions, including standing with/without visual stimulation and with/without gripping a 300-g object (short wooden stick) in the dominant hand.
RESULTS: Compared to control individuals, participants with TBI showed greater instability under all experimental conditions. Visual stimulation increased postural oscillations in the sagittal plane by 35-63% (p <0.05) across groups. Gripping a stick reduced the stimulation-induced instability in sagittal plane by nearly 19-29% (p < 0.05), although the baseline level was not reached in either group.
CONCLUSION: The stabilizing effect of gripping an external object in individuals with TBI was confirmed. A possibility of using this effect as a balance aid strategy requires further investigation.
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