Speech to noise ratio improvement induces nonlinear parietal phase synchrony in hearing aid users

Payam Shahsavari Baboukani; Carina Graversen; Emina Alickovic; Jan Østergaard

doi:10.3389/fnins.2022.932959

Speech to noise ratio improvement induces nonlinear parietal phase synchrony in hearing aid users

Front Neurosci. 2022 Aug 9:16:932959. doi: 10.3389/fnins.2022.932959. eCollection 2022.

Authors

Payam Shahsavari Baboukani¹, Carina Graversen^{2

3}, Emina Alickovic^{4

5}, Jan Østergaard¹

Affiliations

¹ Department of Electronic Systems, Aalborg University, Aalborg, Denmark.
² Integrative Neuroscience, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark.
³ Department of Health Science and Technology, Center for Neuroplasticity and Pain (CNAP), Aalborg University, Aalborg, Denmark.
⁴ Eriksholm Research Centre, Snekkersten, Denmark.
⁵ Department of Electrical Engineering, Linköping University, Linköping, Sweden.

Abstract

Objectives: Comprehension of speech in adverse listening conditions is challenging for hearing-impaired (HI) individuals. Noise reduction (NR) schemes in hearing aids (HAs) have demonstrated the capability to help HI to overcome these challenges. The objective of this study was to investigate the effect of NR processing (inactive, where the NR feature was switched off, vs. active, where the NR feature was switched on) on correlates of listening effort across two different background noise levels [+3 dB signal-to-noise ratio (SNR) and +8 dB SNR] by using a phase synchrony analysis of electroencephalogram (EEG) signals.

Design: The EEG was recorded while 22 HI participants fitted with HAs performed a continuous speech in noise (SiN) task in the presence of background noise and a competing talker. The phase synchrony within eight regions of interest (ROIs) and four conventional EEG bands was computed by using a multivariate phase synchrony measure.

Results: The results demonstrated that the activation of NR in HAs affects the EEG phase synchrony in the parietal ROI at low SNR differently than that at high SNR. The relationship between conditions of the listening task and phase synchrony in the parietal ROI was nonlinear.

Conclusion: We showed that the activation of NR schemes in HAs can non-linearly reduce correlates of listening effort as estimated by EEG-based phase synchrony. We contend that investigation of the phase synchrony within ROIs can reflect the effects of HAs in HI individuals in ecological listening conditions.

Keywords: electroencephalography; hearing impaired; listening effort; local connectivity; noise reduction; phase synchrony.