P37 Neural speech tracking in age related hearing loss as a function of hearing aid use
Age-related hearing loss (ARHL) is associated with difficulty understanding speech, particularly in the presence of background noise. Hearing aids do not (sufficiently) filter background noise, while the use of audio-visual (AV) speech cues can contribute greatly to speech comprehension in noise. Nevertheless, the underlying neural processes of the facilitative role of visual speech cues is not well understood, especially in hearing aid users. The aim of this study was to investigate the effects of AV vs. audio only (A) listening conditions on neural speech processing in two groups of hearing-impaired older adults: 1) hearing aid users and 2) without hearing aid experience. To test neural speech processing, we used neural speech tracking, a measure that reflects the synchronization of low frequency auditory cortex activity with the temporal regularity of a continuous speech signal, which has been shown to be enhanced in ARHL and was correlated with better speech comprehension. Seventy-eight older adults (aged 64-80 years) with ARHL (31.05 - 59.6 dB HL averaged from 0.5-8 kHz) participated. Hearing aid user and those without hearing aid experience groups (both n = 39) were carefully matched for age and hearing loss. They were presented with natural sentences with babble noise (8 overlapping sentences; SNR = 0) in A and AV (showing speaker's mouth and chin) settings while EEG was recorded. An intelligibility task and a comprehension task were performed. Speech tracking will be estimated by cross-correlation, which assesses the similarity between two time series across time lags. Using generalized mixed models, there was a significant improvement in both tasks for both groups as a function of visual cues. Hearing aid users performed significantly better in the comprehension task, but significantly worse in the intelligibility task compared to those without hearing aid experience. We are currently investigating to what extent these effects are reflected in the neural tracking. We hypothesize that speech tracking will decrease as a function of hearing aid use, enhanced by AV information, which would suggest that the hearing aid partially substitutes neural compensation of ARHL. Answering these questions can provide valuable insight for future optimization of hearing loss treatment, particularly the role of AV information in hearing aid implementation.