Binaural Auditory Processing Among Middle-­Aged Adults

Binaural listening, or listening with both ears, allows a listener to better localize and understand speech than with one ear alone. For some aging adults, however, this binaural advantage does not exist, or is reduced relative to normal for speech-in-noise tasks. In addition, some older adults tend to exhibit an exaggerated right ear-­advantage (REA), or better recognition of signals presented to the right ear than the left during dichotic listening tasks, compared to young adults (i.e., Noffsinger et al., 1996). There is limited research, however, exploring if these age-­related changes in binaural listening begin to be demonstrated in mid-­life. The present study examined binaural versus monaural processing for 30 middle-­aged adults (ages 31-­59 years) possessing no more than a mild high-­frequency sensorineural hearing loss. Two types of word recognition assessments were implemented: (1) word recognition in noise and (2) dichotic word recognition. For the word recognition in noise tasks, subjects responded under three conditions: (1) monaural left ear, (2) monaural right ear, and (3) binaural. For the dichotic listening tasks, subjects responded in: (1) free recall, (2) directed-­recall right, and (3) directed-­recall left. Results were compared to previously-collected data for 30 young adults (ages 18-­30 years) and 30 older adults (ages 60-­89 years). Overall, middle-­aged adults performed slightly poorer than young adults but showed performance patterns more similar to young than older adults. In sum, these results suggest that age-related binaural auditory processing deficits may not present in middle age. Results do suggest, however, that individual variability exists within this age group and that individual performance patterns should be considered when making conclusions about binaural auditory processing in middle age. The present study supports future research regarding age-­related changes in the auditory system across the adult lifespan