Age-Related Changes in Sound Image Localization during Lateral Gaze

Introduction: Sound image localization is affected by eye position; however, the effect of aging on this process is unclear. This study aimed to examine the effects of age-related changes on sound image localization during lateral gaze. Methods: The subjects were 34 healthy individuals (8 men and 26 women) aged 23-63 years. The binaural input sound was set to 500 Hz band noise at 50 dB, the time difference was set to 100 μs with an audiometer, and the interaural time difference discrimination threshold was measured. A sawtooth wave was recorded when the subject changed the time difference between the left and right input sounds and moved the sound image to the center. During the measurement, the subject gazed at 0-30° to the right or 30° to the left. Results: The deviation of the medial axis during gaze was significantly higher in the middle-aged and elderly group (patients aged 〓40 years) than in the young age group (patients aged <40 years), but there was no significant difference in the deviation ratio between both groups at 0° gaze. There was no significant between-group difference in the amplitude. Conclusions: The medial axis is more significantly deviated in the gaze direction in the middle-aged and elderly group than in the young age group. This indicates that eye position interference has a greater effect on sound localization in middle-aged and elderly people.