Kiyoshi Yonemoto

Body balance function of cochlear implant patients with and without sound conditions

OBJECTIVE The relation between well-controlled auditory stimulation through cochlear implant (CI) and the body balance has been sparsely investigated. The purpose of this study was to evaluate the body balance function of CI patients with- and without-sound in anechoic sound-shielded room. METHODS We recorded 8 experienced CI recipients and 8 young normal-hearing volunteers. All subjects were assessed using posturography under 4 conditions: (1) eyes open with-sound, (2) eyes closed with-sound, (3) eyes open without-sound, and (4) eyes closed without-sound. RESULTS The total path length and the total area were significantly larger in the eyes closed condition than in the eyes open condition. In normal hearing subjects, the average displacement of center of pressure (COP) in the mediolateral direction under with-sound condition was not different from that under without-sound condition. In CI recipients, the COP significantly displaced to the CI side after the deprivation of visual cues in without-sound condition. This shift was eliminated in with-sound condition (significant interaction among sound condition, eye condition, and between-group factor). CONCLUSION In CI subjects, sound stimulation improves the abnormal displacement of COP in the mediolateral direction. SIGNIFICANCE A posturographic study under an anechoic condition proved that sound stimulation improves body balance function in CI subjects.