Age-Related Differences in Post-Stimulus Alpha and Theta Oscillations: An EEG Study on Audiovisual Speech Processing in a Multi-Talker Scenario
* Presenting author
Abstract:
Visual speech information supports processing of acoustic speech stimuli and the understanding of spoken language in difficult listening scenarios, e.g. in “cocktail-party” situations. It also supports older adults with deficits in speech processing.The current EEG-study investigated oscillatory alpha- and theta-band power in a multi-talker scenario with unexpected changes in target talker location. The aim was to clarify the connection between alpha-band activity and attentional allocation, as well as theta-band activity and the effective integration of multimodal speech input. We further investigated age-related differences. Older and younger participants were presented with videos from two concurrent talkers displayed with (a) audio-visually congruent, (b) auditory (visually unspecific) or (c) visual (auditorily unspecific) speech information. Participants had to discriminate between two target words (“Yes”/ “No”). In each trial, one target word together with a concurrent distractor (digits “one” to “ten”) was presented. Targets were mostly presented from an expected location with rare (20%) switches occurring.The analyses focus on the role of theta oscillations in successful multimodal speech integration, highlighting age-related differences in alpha and theta modulations. Consequently, this adds to the association of underlying brain mechanisms and age-related difficulties in processing speech.