Walking speed and vestibular disorders in a path integration task

Abstract

The goal of this study was to determine if parameters of gait are related to the path integration deficits in some people with vestibular disorders. We tested normals, and two groups of vestibularly impaired people, with unilateral benign paroxysmal positional vertigo and with unilateral weakness. Each group had 20 subjects. They walked straight ahead for 7.62 m, with eyes open or closed, to the beat of a metronome at 60 beats/min, 120 beats/min and 176 beats/min. When adjusted for age and sex, normals veered significantly less and walked significantly further before veering than the unilateral weakness group; all groups veered significantly less at 120 beats/min than the slower or faster cadences. Older patients walked slightly but significantly slower than younger patients at the faster speeds. Step length did not differ among diagnostic groups. These data confirm the involvement of vestibular function in path integration, suggest a differentiation by type of vestibular impairment, and suggest some differences by cadence.

Figure 1

Diagram of the task for a subject who veered to the left. Subjects were instructed to start at the starting line and walk this distance, T (T=7.62 m.). (Feet are not to scale.) Subjects who veered to either side walked the distance, d, to point, V, at which they veered some angle, φ, continuing along the trajectory, h, to cross the finish line at point a, h, having moved laterally through the distance, a. (From (5) and used by permission of IOS press.)