Dual-task costs of listening while driving in older adults with and without audiometric hearing loss: Behavioural and neurophysiological outcomes.

Age-related hearing loss may increase listening difficulties in challenging listening conditions (e.g., speech-in-noise), limiting cognitive resources available to perform common, complex multitasking behaviours like listening while driving. Older adults with hearing loss may compensate by increasing prefrontal cortex (PFC) activation in response to multitasking demands. Few realistic, controlled studies have examined how competing attentional demands of listening while driving affect performance and brain activation, and how these patterns may differ between older adults with and without audiometric hearing loss. This study examined dual-task costs and neural activation levels during a listening-while-driving task in 28 older adults with normal hearing (Mage = 71.79 years) and 22 older adults with hearing loss (Mage=74.00 years) using functional near-infrared spectroscopy (fNIRS). Participants completed a driving task in a high-fidelity driving simulator under simpler (Rural) and more complex (City) conditions and the Connected Speech Test (CST) at +4 dB and 0 dB signal-to-noise ratios (SNR; easier and harder listening respectively). They also performed both tasks simultaneously to examine dual-task costs. fNIRS was recorded during all conditions. Results demonstrated that older adults with hearing loss showed poorer listening accuracy, poorer driving performance, and greater oxygenation concentration in the PFC than those with normal hearing. Both groups showed poorer listening and driving performance in the dual-task compared to the single-task conditions, with the greatest dual-task costs observed during the most difficult condition (City driving, 0 dB SNR). Broadly, these findings could inform strategies to optimize vehicle acoustics and reduce auditory distractions, thereby supporting driving performance in challenging driving conditions.