Right-Ear Advantage for Unaided and Aided Speech Perception in Noise in Older Adults

To investigate whether the magnitude of the right-ear advantage (REA) for speech perception in noise decreased in aided conditions as compared with unaided conditions in older adults bilaterally fitted with hearing aids. A secondary aim was to determine the effect of audibility on the right- and left-ear processing for speech stimuli in both aided and unaided conditions. Forty-two older adult, bilateral hearing-aid users were selected. Pure-tone audiometry and the hearing-in-noise test (HINT) were carried out and real-ear insertion gain (REIG) was measured in all participants. All HINT stimuli were delivered via loudspeakers in the free field in both aided and unaided conditions. Right-ear scores for HINT were significantly better than the left ear in both unaided and aided conditions. No significant differences in the magnitude of the REA between the unaided HINT and aided HINT scores were found. Regression models showed that audibility explained 47% and 53% of the variance in unaided HINT scores in the right and left ears, respectively. For the aided HINT scores, age and audibility explained 46% of the variability for the left-ear scores, while for the right ear, the only remaining significant variable in the model was REIG, which explained 12% of the right-ear HINT scores. Right-ear processing is significantly more efficient for speech stimuli in both unaided and aided conditions in older adults. Audibility affected unaided speech perception in right and left ears similarly however this was not the case in the aided condition. Audibility was associated with aided speech perception in noise in the left ear only.