Age-Related Changes in Interaural-Level-Difference-Based Across-Frequency Binaural Interference

Abstract

Low-frequency interaural time differences and high-frequency interaural level differences (ILDs) are used to localize sounds in the horizontal plane. Older listeners appear to be worse at horizontal-plane sound localization to compared younger listeners, but little is understood about age-related changes to across-frequency binaural processing. This study investigated if the frequency dependence of across-frequency ILD processing is altered for older compared to younger listeners, which was done by using an across-frequency binaural interference task (when the interaural difference sensitivity for a target sound is decreased by a spectrally remote interfering sound with zero interaural differences). It was hypothesized that as listeners experience advancing age and age-related high-frequency hearing loss (i.e., presbycusis), they will demonstrate worse binaural performance and experience more across-channel binaural interference (because of age-related temporal processing deficits), and will increasingly be affected by interferers at lower frequencies (because of age-related hearing loss) when compared to younger listeners. There were 11 older (>65 yrs) and 20 younger (<30 yrs) listeners with normal to near-normal audiometric thresholds up to 2 kHz. They were tested using a left-right ILD lateralization discrimination task. Single-tone ILD discrimination thresholds and across-frequency binaural interference were measured at 0.5, 1, 2, 4, and 8 kHz. ILD thresholds and interference were about twice as large for older compared to younger listeners. Interferers ≤1 kHz produced 2–3 times as much across-frequency binaural interference for older compared to younger listeners. Hearing thresholds were significant predictors of single-tone ILD thresholds; in addition, both target and interferer hearing thresholds were significant predictors of binaural interference. The results suggest a reweighting of binaural information that occurs with advancing age and age-related high-frequency hearing loss. This evidence of plasticity may help explain some of the age-related changes in spatial-hearing abilities.

A review of auditory processing and cognitive change during normal ageing, and the implications for setting hearing aids for older adults

“…Binaural processing of TFS and ENV is degraded with age ( 46 , 47 , 52 ) and impairs interaural level difference (ILD) and interaural time difference (ITD) cues ( 23 , 132 ). Use of bilateral hearing aids should not further disrupt theses cues, e.g., via fast gain changes that particularly diminish the aided level difference.…”

“…Reduced binaural processing makes older adults more susceptible to binaural interference ( 132 , 133 ). There is evidence that some individuals may perform better in noisy situations with a unilateral aid ( 134 ) although this is not consistent across studies ( 135 ).…”

The interference of tinnitus on sound localization was related to the type of stimulus

“…Explorative analysis suggested that the sound source localization ability gradually deteriorated with increasing age. Previous studies have consistently shown that despite the generally normal hearing thresholds, sound localization ability generally decreases with age, both in humans (Dobreva et al, 2011;Goupell, 2022;Weissgerber et al, 2022) and in animals (Cheng et al, 2020). Increasing age adversely affects the processing of ITD cues, including both the temporal fine structure and the slowly varying envelope (Weissgerber et al, 2022).…”