Dynamic Balance Control and Segmental Orientation While Listening During Walking: Effects of Age and Hearing Loss

Dynamic control of balance changes with age and changes with declines in sensory and cognitive abilities. For instance, emerging, yet robust associations between hearing loss and poor mobility have been described and yet the mechanism underlying these associations remains unknown. It could be that age-related declines in hearing ability result in different kinematic strategies when having to walk and listen at the same time (e.g. head and body orienting responses toward sounds) and/or that declines in hearing result in increased cognitive load during listening, at the detriment to mobility-related performance. Therefore, this thesis sought to better characterize these associations by comparing the balance control of adults who differ by age or by hearing status by having them perform a listening task with varying levels of difficulty while sitting, standing, or walking. 15 younger adults with normal hearing (YANH), 16 older adults with normal hearing (OANH) and 11 older adults with hearing loss (OAHL) completed four types of listening trials while walking along a 5-6 m path. The listening trial types included no auditory stimuli (No Sound), multitalker babble (Babble Only), and a target sentence presented at a High signal-to-noise ratio (SNR) (i.e. low listening load) and at a Low SNRs (i.e. high listening load). Kinematic parameters of interest included those related to dynamic balance control and segmental orientation. Listening accuracy was also measured. Comparisons by age group (YANH vs. OANH) and by hearing status (OANH vs. OAHL) revealed that the balance control of all individuals differed when performing listening tasks while walking compared to when the walking task was performed alone. There was no evidence that altering yaw rotation of the head-in-space was a strategy used by any of the participant groups in the listening task when walking. Among OANH and OAHL groups, poorer objective hearing acuity were significantly associated with reduced trunk roll variability, while better self-reported listening ability was associated with making larger yaw rotations of the head-in-space. Finally, listening accuracy across the sitting, standing, and walking conditions were compared and revealed that increased balance control demands of walking compared with adverse listening (i.e., Low SNR) conditions were more detrimental to the listening accuracy of the OAHL than the OANH group. The findings of this study demonstrate how the dynamic balance control of adults, who differ by age or by hearing status, can be affected by increased cognitive demands of performing a dual – listening and walking task. These findings could provide the foundation for future exploration of whether the use of hearing aid technology will affect the head orientation, trunk control, and task prioritization of older adults with hearing loss