Aging impacts older adults’ ability to divide their attention. Research has shown that cognitive training techniques are promising in improving divided attention. Investigating the effects of training on electrophysiological brain activity might elucidate the mechanisms underlying improvements and allow better training method selection. Electroencephalography (EEG) is ideal for studying divided attention as switching attention is a dynamic process that takes place within milliseconds and requires high temporal resolution.
All participants (mean age 69.5 years, SD=6.42) performed a visual detection task and an alphanumeric equation task under single and dual-task conditions. Afterwards, participants were randomly assigned to three groups: The single task training group (STT, N=13) practiced the two tasks separately; the fixed attention training group (FAT, N=12) was trained to assign equal attention to both tasks concurrently; the variable-attention training group (VAT, N=14) was trained to flexibly vary their attention while performing the tasks concurrently. After training, participants were tested again. EEG measures were taken pre- and post-training.
Training led to behavioural improvements in all of our participants, with the VAT group displaying the greatest benefits and a reduction in dual-task costs. The N1 component was less pronounced after training while P2 was enhanced, suggesting more efficient processing. Functional connectivity measures indicated an increase in theta band coherence between fronto-parietal and fronto-occipital regions in the VAT group, suggesting improved cognitive control. Our results suggest that variable attentional allocation training incurred behavioural benefits with an electrophysiological profile distinct from single task practice and equal priority dual-task training
