Rate Discrimination Training May Partially Restore Temporal Processing Abilities from Age-Related Deficits

Abstract

The ability to understand speech in complex environments depends on the brain’s ability to preserve the precise timing characteristics of the speech signal. Age-related declines in temporal processing may contribute to the older adult’s experience of communication difficulty in challenging listening conditions. This study’s purpose was to evaluate the effects of rate discrimination training on auditory temporal processing. A double-blind, randomized control design assigned 77 young normal-hearing, older normal-hearing, and older hearing-impaired listeners to one of two treatment groups: experimental (rate discrimination for 100- and 300-Hz pulse trains) and active control (tone detection in noise). All listeners were evaluated during pre- and post-training sessions using perceptual rate discrimination of 100-, 200-, 300-, and 400-Hz band-limited pulse trains and auditory steady-state responses (ASSRs) to the same stimuli. Training generalization was evaluated using several temporal processing measures and sentence recognition tests that included time-compressed and reverberant speech stimuli. Results demonstrated a session × training group interaction for perceptual and ASSR testing to the trained frequencies (100 and 300 Hz), driven by greater improvements in the training group than in the active control group. Further, post-test rate discrimination of the older listeners reached levels that were equivalent to those of the younger listeners at pre-test. Generalization was observed in significant improvement in rate discrimination of untrained frequencies (200 and 400 Hz) and in correlations between performance changes in rate discrimination and sentence recognition of reverberant speech. Further, non-auditory inhibition/attention performance predicted training-related improvement in rate discrimination. Overall, the results demonstrate the potential for auditory training to partially restore temporal processing in older listeners and highlight the role of cognitive function in these gains.

Cochlear-implant listeners benefit from training with time-compressed speech, even at advanced ages

“…It remains the case, however, that training that targets temporal-processing abilities specifically for older CI users has the potential to be particularly beneficial because it targets a pervasive auditory limitation of older people. Moreover, large gains can be observed in older acoustic-hearing listeners with a training regimen focused on auditory temporal processing ( Anderson et al , 2022 ).…”

“…1(B) ]. It is assumed that training with time-compressed speech engenders auditory learning of abbreviated acoustic speech cues ( Golomb et al , 2007 ), improves a listener's attention to the speech materials, and/or improves general auditory temporal-processing abilities, as demonstrated with nonspeech stimuli in acoustic-hearing listeners ( Anderson et al , 2022 ) and CI listeners ( Goldsworthy and Shannon, 2014 ; Bissmeyer et al , 2020 ). However, without a control group, it is not possible to determine if primarily perceptual or procedural learning occurred.…”

“…For example, auditory training improved temporal rate discrimination in two older (≥65 years of age) CI listeners of the six tested when presented with single-electrode stimulation ( Goldsworthy and Shannon, 2014 ). Rate discrimination also improved for acoustic-hearing listeners when presented band-limited pulse trains; furthermore, older acoustic-hearing listeners improved temporal-processing abilities to levels of untrained younger listeners ( Anderson et al , 2022 ). However, the benefit of auditory training focused on improving the processing of speech signals that stress rapid temporal processing has yet to be assessed in older CI listeners.…”

“…In the central auditory system, hearing impairment may contribute to loss and limited activation of neurons, for example, in the inferior colliculus and auditory cortex ( Middlebrooks and Snyder, 2010 ; Kirby and Middlebrooks, 2012 ). Central deficits impact temporal representations of auditory signals, resulting in a less precise, degraded signal ( Anderson et al , 2012 ; Anderson et al , 2022 ).…”

“…The current study is an initial effort to evaluate the benefit of an adaptive training paradigm with time-compressed speech for adult CI listeners across the lifespan. We hypothesized that listeners would demonstrate improved recognition of rapid speech after completion of auditory training, based on previous studies showing improved pulse-rate discrimination following training ( Goldsworthy and Shannon, 2014 ; Bissmeyer et al , 2020 ; Anderson et al , 2022 ). Although older CI listeners were expected to demonstrate improved recognition of rapid speech following training, it was also hypothesized that the training gains would diminish with increasing age (i.e., there would be an age by training interaction resulting in more modest training gains for older listeners).…”