聴神経腫瘍例における歩行運動の3次元動作解析

Abstract

Many patients with acoustic neuromas complain of hearing loss, tinnitus or equilibrium disturbance. In our previous gait studies using tactile sensors placed under both feet, we demonstrated that the presence of an acoustic neuroma could cause unstable gait. Three dimensional motion analysis is a useful tool to assess abnormal gait performance. The purpose of this study was to examine the gait performance with spatiotemporal and kinematic parameters using three dimensional motion analysis in patients with acoustic neuromas. Seventeen patients (7 males, 10 females; mean age: 64.1±11.1 years old) with a unilateral acoustic neuroma were enrolled in this study. Twenty-one healthy subjects (12 males, 9 females; mean age: 37.6±19.1 years old) served as controls. Subjects were asked to walk freely with eyes open or closed for a distance of nearly 4 m. Spatiotemporal and kinematic components, including gait speed, stride length, stride duration, % stance phase, step width, head movements (vertical, yaw, pitch, and roll), gait deviation, forefoot motion, and angle between foot and floor (foot flexion angle) during walking, were calculated using three dimensional coordinates. At the subject's heel strike during walking, the mean foot flexion angle in the patient group was significantly smaller than the mean value in the healthy subjects. The decrease of the angle in the acoustic neuroma patients may be associated with a gait abnormality caused by vestibular disorders. Based on three dimensional motion analysis, we propose a useful parameter to evaluate the vestibular disorders in patients with an acoustic neuroma.