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Age-related changes in audiovisual speech integration
Poster Session E, Friday, October 2, 11:00 am - 1:00 pm, Wangari Maathai
Charlie Reynolds1,2, Ole Jensen3, Katrien Segaert1,2, Hyojin Park1,2; 1School of Psychology, University of Birmingham, Birmingham, UK, 2Centre for Human Brain Health (CHBH), University of Birmingham, Birmingham, UK, 3Department of Experimental Psychology, University of Oxford, Oxford, OX2 6GG, UK; Oxford Centre for Human Brain Activity, Oxford Centre for Integrative Neuroimaging, Department of Psychiatry, University of Oxford, Oxford, OX3 7JX, UK
Successful speech comprehension in complex listening environments depends on the flexible integration of auditory and visual information. While recent work has shown that temporally aligning visual speech with the auditory envelope improves comprehension in younger adults, it remains unclear whether this mechanism is preserved in ageing. In a pre-registered study (https://doi.org/10.17605/OSF.IO/2P43X), participants completed a dichotic audiovisual speech listening task in which they were asked to attend to speech in one ear (task-relevant) while ignoring speech in the other ear (task-irrelevant). Magnetoencephalography (MEG) was combined with Rapid Invisible Frequency Tagging (RIFT) to measure the brain’s response to a high-frequency flicker over a speaker’s lip region, with its amplitude driven by either the task-relevant or task-irrelevant speech. Behaviourally, older adults (N=36) showed reduced comprehension accuracy and longer reaction times relative to younger adults (N=40) selectively when visual information was task-relevant. The coherence between the visual flicker (RIFT), and the brain responses was stronger in task-relevant than task-irrelevant conditions similarly for older and younger adults. Conversely, the coherence between the auditory signal and the brain responses was decreased in the task-relevant condition compared to the task-irrelevant condition similarly for both age groups. This shows that both age groups are sensitive to RIFT. Intermodulation frequencies, reflecting nonlinear interactions between tagged auditory and visual inputs, revealed greater left-lateralised inferior frontomotor and temporal areas activity for task-relevant relative to task-irrelevant conditions in older adults. In younger adults, intermodulation responses were in the left motor/premotor area. Ongoing analyses will statistically compare intermodulation responses across age groups. Together, these findings indicate that age-related reductions in performance are associated with changes in the neural signatures of multisensory integration. This is in line with broader literature on age-related decline in feature binding and higher-level cognitive integration processes.
Topic Areas: Speech Perception,