P30Session 2 (Friday 13 January 2023, 09:00-11:00)The influence of auditory training on behavioral and electrophysiological measures of gap detection in younger and older adults
Structural and functional age-related changes have been found to affect auditory processing and limit speech perception in adverse listening situations. Moreover, the deterioration in the ability to process rapid changes in auditory input with age seems to play a primary role in the difficulty many older listeners experience perceiving speech. One measure which is commonly used to assess temporal processing is the listener’s ability to detect a quiet gap in a sound (gap detection, GD). The current study investigated whether training using between-channels GD tasks could improve the ability of younger and older adults to detect brief quiet gaps marked by two noise-bands centered at different frequencies. In addition, once training was completed, generalization was tested using novel markers centered at novel frequencies: 1kHz-2kHz (frequencies used in the training condition but in the reversed order), 2kHz-2kHz (using the first marker of the training condition), 1 kHz -1 kHz (using the second marker of the training condition), 1.5 kHz -0.5 kHz (a novel frequency marker), and 2 kHz -1kHz (using the same markers in the training condition played to the untrained ear). Lastly, one month later participants are tested using these conditions once again in order to evaluate training retention.
Ninety-six younger and 96 older clinically normal hearing adults were divided into a training group and six control groups (one for each condition tested). The training group had twelve older and twelve younger adults who completed 10 days of training detecting between-channel silent gaps marked by narrow-band noise centered at 2kHz and 1kHz. During the 10 days of training gap, detection thresholds are measured 10 times using an adaptive 2 down 1 up 3I3AFC. The same procedure is used to assess generalization and retention. To look for changes in cortical processes due to training, pre-and post-training Evoked Potential Response (ERP) measures were obtained. Generalization was examined at the end of the training and retention was examined 1 month later. The behavioral results imply that a model in which the rate of improvement with training is the same for younger and older adults provides a good fit for the data. The only statistically-significant difference between younger and older adults is that the younger adults’ asymptotic gap detection thresholds are significantly lower than those of older adults. This model, the results found for generalization, and retention, as well as the electrophysiological evidence, will be further discussed.