Desynchronisation of auditory steady-state responses related to changes in interaural phase differences: an objective measure of binaural hearing

Abstract

Objective: Binaural processing can be measured objectively as a desynchronisation of phase-locked neural activity to changes in interaural phase differences (IPDs). This was reported in a magnetoencephalography study for 40 Hz amplitude modulated tones. The goal of this study was to measure this desynchronisation using electroencephalography and explore the outcomes for different modulation frequencies. Design: Auditory steady-state responses (ASSRs) were recorded to pure tones, amplitude modulated at 20, 40 or 80 Hz. IPDs switched between 0 and 180° at fixed time intervals. Study sample: Sixteen young listeners with bilateral normal hearing thresholds (≤25 dB HL at 125–8000 Hz) participated in this study. Results: Significant ASSR phase desynchronisations to IPD changes were detected in 14 out of 16 participants for 40 Hz and in 8, respectively 9, out of 13 participants for 20 and 80 Hz modulators. Desynchronisation and restoration of ASSR phase took place significantly faster for 80 Hz than for 40 and 20 Hz. Conclusions: ASSR desynchronisation to IPD changes was successfully recorded using electroencephalography. It was feasible for 20, 40 and 80 Hz modulators and could be an objective tool to assess processing of changes in binaural information.

Keywords:

• Electroencephalography
• auditory steady-state responses
• binaural hearing
• interaural phase differences
• modulation frequency

Acknowledgements

We want to thank all participants who made time to participate in this study.

The project was financed by the Research Council, KU Leuven (grant support: OT/12/98) and the European Research Council (ERC) under the European Union’s Horizon 2020 Research and Innovation Programme (grant agreement No. 637424, ERC starting Grant).

Portions of the data presented in this technical report were presented by Charlotte Vercammen at HEaring Across the Lifespan at Lake Como, Italy (5–7 June 2014) and at the Twelfth Congress of The European Federation of Audiology Societies (EFAS) at the Green Park Pendik Convention Centre, Istanbul, Turkey (27–30 May 2015).

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.