Think of your ears as a team of detectives trying to locate the source of a sound. As you age, these detectives might start to lose some of their coordination and communication skills. This study explored how getting older affects the way we process sound information from both ears. The researchers wanted to see if older people experienced more difficulty when it came to determining where a sound is coming from. They found that as people age, their ability to localize sounds becomes less accurate. This decline is especially noticeable in high-frequency sounds, which are important for distinguishing between different sources. Interestingly, this decline in sound localization abilities could be attributed to both reduced hearing sensitivity and changes in binaural processing. The brain’s ability to make sense of sound information from both ears also seemed to be affected by age. These findings suggest that aging affects the mechanism behind our spatial-hearing abilities, which helps us navigate and interact with the world around us. To dive deeper into the details of this research, check out the full article!

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.

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