Head movements in patients with vestibular lesion: a novel approach to functional assessment in daily life setting.

OBJECTIVES: (1) To determine if head movements in patients with vestibular deficiency differ from those in normal subjects during daily life activities. (2) To assess if these differences can be correlated with patients' perception of dizziness-induced handicap. STUDY DESIGN: Prospective matched-pairs study SETTING: Tertiary referral center PATIENTS: Thirty-one vestibular schwannoma patients with documented postoperative unilateral vestibular loss and their age-, gender-, and physical activity level-matched controls with symmetric vestibulo-ocular reflexes. INTERVENTIONS: Head movements during 10 tasks from daily life were recorded using body-worn movement sensors. MAIN OUTCOME MEASURES: The time to complete the task, the average head velocity and acceleration during each task, and the number of head turns performed were compared between cases and controls. These measures were then correlated with the self-reported Dizziness Handicap Inventory (DHI) scores of the patients. RESULTS: Patients with a unilateral vestibular deficit took significantly longer to perform most daily life activities compared to controls. Their head movements, however, were not always slower. They adopted a different movement strategy, in certain instances less efficient and more disorganized. Dimensions of movement are not all affected equally after a unilateral vestibular loss with evidence of clear clustering of the differences within dimensions across tasks. There was no correlation between the DHI and patients' performance in those tasks. CONCLUSION: Vestibular loss, even when compensated, affects patients' movements, which can be measured in an ambulatory setting of daily life activities. The differences in movements associated with vestibular loss do not correlate with the degree of self-reported handicap.