1 Department of Psychology/Centre for Research in Human Development, Concordia University, Montréal, QC, Canada.
2 School of Health, Concordia University, Montréal, QC, Canada.
3 Department of Psychology, University of Toronto, Toronto, ON, Canada.
4 KITE-Toronto Rehabilitation Institute, University Health Network, Toronto, ON, Canada.
5 Department of Medicine, Division of Geriatric Medicine, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada.
6 Gait and Brain Lab, Parkwood Institute, Lawson Health Research Institute, London, ON, Canada.
7 Department of Epidemiology and Biostatistics, Schulich School of Medicine & Dentistry, Western University, London, ON, Canada.
8 Département de Médecine, Université de Montréal, Montréal, QC, Canada.
9 Centre de Recherche de l'Institut de Cardiologie de Montréal, Montréal, QC, Canada.
10 Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal, Montréal, QC, Canada.
11 Recovery and Performance Lab, Division of Biomedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada.
12 Ontario Shores Centre for Mental Health Sciences, Whitby, ON, Canada.
13 Division of Geriatric Psychiatry, Department of Psychiatry, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada.
14 Department of Medicine (Neurology), University of Alberta, Edmonton, AB, Canada.
15 Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada.
16 Interdisciplinary School of Health Sciences, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada.
17 The Centre for Aging SMART, Vancouver Coastal Health Research Institute, Vancouver, BC, Canada.
18 Djavad Mowafaghian Centre for Brain Health, Vancouver Coastal Health Research Institute, Vancouver, BC, Canada.
19 Department of Kinesiology and Health Sciences, University of Waterloo, ON, Canada.
20 Schlegel-UW Research Institute for Aging, Waterloo, ON, Canada.

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.

Clinical trial registration: https://www.clinicaltrials.gov/ct2/show/NCT02808676, NCT02808676.