Neurocognitive Disorders

MCI eligibility in the SOUND trial is defined as a MoCA-HI score between 18 and 25 inclusive. MCI occupies the intermediate stage between normal age-related cognitive change and dementia. Neurocognitive disorders affect cognitive function, memory, learning, and attention. Alzheimer's disease aetiology is multifactorial, encompassing genetic, neurobiological, environmental, and psychosocial factors. Alzheimer's disease, the most prevalent form of major neurocognitive disorder, is irreversible and progressive, with a prevalence of 3–19% and an incidence of 8–58 per 1,000 person-years. Even when hearing aid use reduces the absolute risk of dementia progression, individuals with MCI remain at substantially greater risk than those without MCI history. Mild neurocognitive disorder affects approximately 10.5% of older adults without dementia, with incidence increasing markedly after age 70. Behavioural interventions that improve and sustain hearing aid use adherence specifically in people with MCI are identified as a priority.