Sustained envelope periodicity representations are associated with speech-in-noise performance in difficult listening conditions for younger and older adults

Abstract

Temporal modulations are an important part of speech signals. An accurate perception of these time-varying qualities of sound is necessary for successful communication. The current study investigates the relationship between sustained envelope encoding and speech-in-noise perception in a cohort of normal-hearing younger (ages 18–30 yr, n = 22) and older adults (ages 55–90+ yr, n = 35) using the subcortical auditory steady-state response (ASSR). ASSRs were measured in response to the envelope of 400-ms amplitude-modulated (AM) tones with 3,000-Hz carrier frequencies and 80-Hz modulation frequencies. AM tones had modulation depths of 0, −4, and −8 dB relative to m = 1 ( m = 1, 0.631, and 0.398, respectively). The robustness, strength at modulation frequency, and synchrony of subcortical envelope encoding were quantified via time-domain correlations, spectral amplitude, and phase-locking value, respectively. Speech-in-noise ability was quantified via the QuickSIN test in the 0- and 5-dB signal-to-noise (SNR) conditions. All ASSR metrics increased with increasing modulation depth and there were no effects of age group. ASSR metrics in response to shallow modulation depths predicted 0-dB speech scores. Results demonstrate that sustained amplitude envelope processing in the brainstem relates to speech-in-noise abilities, but primarily in difficult listening conditions at low SNRs. These findings furthermore highlight the utility of shallow modulation depths for studying temporal processing. The absence of age effects in these data demonstrate that individual differences in the robustness, strength, and specificity of subcortical envelope processing, and not age, predict speech-in-noise performance in the most difficult listening conditions. NEW & NOTEWORTHY Failure to correctly understand speech in the presence of background noise is a significant problem for many normal-hearing adults and may impede healthy communication. The relationship between sustained envelope encoding in the brainstem and speech-in-noise perception remains to be clarified. The present study demonstrates that the strength, specificity, and robustness of the brainstem’s representations of sustained stimulus periodicity relates to speech-in-noise perception in older and younger normal-hearing adults, but only in highly challenging listening environments.

Intra- and interhemispheric white matter tract associations with auditory spatial processing: Distinct normative and aging effects

“…It may be surprising that SNR loss did not relate to age-group. However, this is consistent with other studies examining QuickSIN performance among groups of older listeners that are high-functioning and have limited hearing loss (e.g., McClaskey et al, 2019 ; Sheft et al, 2012 ). More interesting is the lack of a relationship between SNR loss and ITD digit segregation, which may suggest that the subtle individual differences in speech-in-noise identification among normal hearing younger and older listeners as measured by QuickSIN are not sensitive enough to account for variability in ITD digit segregation.…”

Corticothalamic Projections Deliver Enhanced-Responses to Medial Geniculate Body as a Function of the Temporal Reliability of the Stimulus

“…A less temporally distinct ascending acoustic code is thought to engage top-down cognitive resources by generating predictions to support decoding of modulated speech-like signals (Peelle & Wingfield, 2016;Pichora-Fuller et al, 2017;Caspary & Llano, 2018;Recanzone, 2018). Consistent with human and animal studies, the present study finds that weakening periodicity cues by decreasing modulation depth (SAM∆100% to SAM∆25%) decreased the percentage of neurons showing temporal phaselocking to the SAM envelope (Pichora-Fuller et al, 2007;Malone et al, 2010;Parthasarathy & Bartlett, 2011;Mamo et al, 2016;Kommajosyula et al, 2019;McClaskey et al, 2019). Previously we found that jittering the SAM envelope with a 1.0kHZ centered noise produced similar levels of repetition-enhancement to the SAM∆25% used in the present study (Kommajosyula et al, 2019).)…”

The Speech Envelope Following Response in Normal and Hearing Impaired Listeners

“…Alternatively, there is a possibility that cochlear gain loss reduced the EFR and that this behavior was not captured by the current version of the model for this type of stimulus. There is evidence that ageing degrades the ABR EFR (Fernandez et al, 2015;Keshishzadeh et al, 2020), although not every study finds an effect of age on the EFR (McClaskey et al, 2019).…”

“…Alternatively, there is a possibility that cochlear gain loss reduced the EFR and that this behavior was not captured by the current version of the model for this type of stimulus. There is evidence that ageing degrades the ABR EFR (Fernandez et al, 2015; Keshishzadeh et al, 2020), although not every study finds an effect of age on the EFR (McClaskey et al, 2019). Additionally, recent invasive studies in mice have shown that, although ageing leads to a reduction of the sustained phase locked response at the level of spiral ganglion neurons, this effect is partially neutered by a compensatory gain mechanism effective in the IC (Parthasarathy et al, 2019).…”