The Role of Attention in Vestibular Processing

This study investigated the hypothesis that vestibular processing is facilitated by attention, and that suppression of the vestibule-ocular reflex will lead to dual-task interference in a secondary information processing task. Twelve patients with surgically confirmed absent unilateral vestibular function and twelve healthy age-matched controls participated in this study. All subjects underwent vestibular stimulation through two different types of rotational conditions, one a semicircular canal stimulus and the other an otolith stimulus, two different visual conditions (darkness and fixation of a laser point) and pursuit tracking of a moving laser point. Subjects also performed one of three different secondary information processing tasks (IPT) while undergoing the vestibular condition. The results of this study showed that dual-task interference occurs during vestibular stimulation in both patients and healthy controls, and this interference was more pronounced in patients during more complex IPTs. The results also found no overall difference in performance of a secondary cognitive task when subjects suppressed the vestibule-ocular reflex by fixating during rotation. These results may suggest that cognitive processing is a necessary component for integration of vestibular information, and this requirement may be greater in patients with unilateral vestibular loss.