Extracting auditory cortex source signals for improving speech envelope reconstruction from EEG data

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Vanheusden, FJ ORCID: https://orcid.org/0000-0003-2369-6189, Nel, S, Perry, SM, Simpson, DM and Bell, SL, 2018. Extracting auditory cortex source signals for improving speech envelope reconstruction from EEG data. In: Auditory EEG Signal Processing (AESoP) Symposium, Leuven, Belgium, 21-23 May 2018.

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Abstract

Objectives: To improve correlations between speech envelopes and envelopes reconstructed from EEG data by weighting EEG channels based on auditory cortical source signal contributions.

Methods: The forward model was developed based on an equivalent double layer source distribution in a standard volume conductor model including the brain and scalp. Electrode contributions were weighted based on average signal ratios between individual electrode pairs from the forward solution. Data were collected from 19 normal hearing subjects using a 32-channel EEG system. Four 3-minute speech fragments were presented at 75 dB A SPL through a loudspeaker positioned 1.2 m in front of the subject. Distribution of electrode weights followed an exponential function. EEG data were resampled to 64 Hz and bandpass filtered between 2 and 8 Hz to focus on responses to slow speech modulations. After re-referencing to the average over all electrodes, EEG responses to speech were segmented and their forward solution weight applied. For each participant, envelopes were reconstructed with the mTRF-toolbox using cross-validation. Correlations were compared against reconstructions without using forward solution weights. Significance of correlations was assessed through bootstrapping.

Conclusions: Correlations using forward-solution weights did not significantly improve. Including a priori information on source project to the scalp might only provide limited benefit in reconstructing speech envelopes.

Item Type:	Conference contribution
Alternative Title:	Improving speech envelope reconstruction from EEG data using electrode weighting based on a forward solution
Creators:	Vanheusden, F.J., Nel, S., Perry, S.M., Simpson, D.M. and Bell, S.L.
Date:	2018
Divisions:	Schools > School of Science and Technology
Record created by:	Jonathan Gallacher
Date Added:	12 Dec 2018 16:30
Last Modified:	12 Dec 2018 16:30
URI:	https://irep.ntu.ac.uk/id/eprint/35314