Older adults find it more difficult than younger adults to allocate attentional resources between co-occurring multisensory tasks, such as perceiving speech-in-noise whilst maintaining balance. Attentional control may be reflected in oscillatory alpha activity, with increases in activity reflecting inhibition of different brain regions and decreases reflecting neural activation. This study investigated how younger and older adults reallocate attentional resources during dual-task speech perception and balance, and how these age-related changes are reflected in alpha activity.

Twenty-four younger adults (18-35 years old) and twenty-one older adults (60-80 years old) identified words in audiovisual sentences extracted from the Grid corpus. Participants completed this speech perception task with or without background noise, whilst standing in easy or difficult balance positions. Fronto-central and parieto-occipital alpha activity was recorded using EEG, to measure activation in brain regions associated with balance maintenance and audiovisual speech perception, respectively.

Mixed ANOVAs revealed that speech-in-noise performance was strongest during the challenging balance condition, in contrast to our hypotheses. Whilst these behavioural effects were not reflected in parieto-occipital alpha power, decreases in fronto-central alpha power were greater in clear listening conditions. Taken together, increasing cognitive load may not always be detrimental to balance in physically and cognitively fit older adults.