The effect of hearing ability on dual-task performance following multi-domain training in older adults with mild cognitive impairment: findings from the SYNERGIC trial

Abstract

Background: Hearing loss is one of the largest potentially modifiable risk factors for dementia and is linked with poor cognitive-motor dual-task performance (e.g., walking while performing a cognitive task). Hearing loss is more prevalent and severe in males, whereas dementia is more prevalent in females. Physical exercise and cognitive interventions appear promising in improving dual-tasking in older adults; however, it is currently unclear whether hearing ability affects training efficacy on dual-task outcomes in older adults with mild cognitive impairment (MCI), and whether sex influences this effect.

Objective: The primary aim of this study was to examine whether hearing ability affects dual-task performance at baseline and after training in individuals with MCI, and whether sex further influences these relationships, irrespective of intervention arm.

Methods: Secondary data was analysed from 75 participants with MCI (M_age = 73.66 ± 6.67) enrolled in the SYNERGIC trial. Hearing ability was assessed using self-report and behavioral measures. Participants completed a 20-week intervention: (1) Exercise (aerobic-resistance exercise + sham cognitive training; n = 31), (2) Multi-Domain Training (aerobic-resistance exercise + cognitive training; n = 32), or (3) Placebo Training (balance and toning exercises + sham cognitive training; n = 12). Primary outcomes included dual-task gait and cognitive performance.

Results: At baseline, poorer hearing predicted worse dual-task performance, particularly in males. Dual-task gait variability significantly improved following Multi-Domain Training in participants with a greater degree of self-reported hearing complaints. Sex-stratified analyses revealed that females with more hearing complaints improved more across all interventions, while in the Multi-Domain group, males with poorer objective hearing and females with better hearing showed the greatest gains. Additionally, in those with poorer hearing, lower cognitive scores (MoCA) predicted greater improvements after Multi-Domain Training, but a decline after Placebo Training.

Conclusion: Hearing ability, sex, and cognitive status appear to interact to influence the effects of exercise and cognitive training on dual-task performance in older adults with MCI. Multi-Domain Training appears particularly beneficial for those with hearing loss (who are male and/or have lower cognitive status), highlighting the need for personalized interventions to preserve function and slow decline in this at-risk population.

Plain Language Summary

Background: Older adults who walk more slowly while simultaneously competing a cognitive task (i.e., dual-tasking) are at an increased risk for cognitive decline. Hearing loss is one of the largest risk factors for dementia, and it may be possible to reduce this risk.  It is also linked with poor performance while doing two tasks at once (dual-task performance). Hearing loss is more common and severe in males, while dementia is more common in females. Exercise and cognitive training have shown promise in improving dual-task performance in older adults, but it remains unclear whether hearing level moderates the effectiveness of such interventions in older adults with mild cognitive impairment (MCI) – a transitional state between normal cognitive aging and dementia – or if sex plays a role.

Seventy-five participants with MCI participated in one of three types of interventions for 20 weeks to determine if it would improve dual-tasking more so for those who had a greater degree of hearing loss. The three types of interventions consisted of: 1) aerobic-strength exercises with cognitive training, 2) aerobic-strength exercises with a placebo cognitive training, or 3) balance and toning exercises with a placebo cognitive training.

Prior to training, dual-task walking and cognition were poorer in participants with worse hearing, particularly in males. Following combined exercise and cognitive training, dual-task walking became more stable, particularly in males with a greater degree of hearing loss, and in older adults with poorer hearing and lower cognitive status. These findings can help guide interventions to improve multitasking abilities and reduce decline in older adults at risk for dementia.