The Epidemiology of Cognitive Impairment in the Aging Population: Implications for Hearing Loss

Cognitive impairment and dementia are characterized by a progressive and devastating reduction in most cognitive abilities, functional independence, and social relationships. Dementia represents a substantial financial burden on society, one that is comparable to the financial burden of heart disease and cancer. Due to its insidious onset, cognitive impairment can be clinically silent for several years; therefore, diagnosis occurs late in the disease process, and treatment becomes almost useless. The identification of predictors of dementia may help identify the pathophysiological mechanisms underlying the disease and lead to the development of a more effective medical diagnosis and therapy, and thus an early treatment. Review of the literature suggests that in those individuals with less cognitive impairment (normal/predementia group), hearing loss has an association with language comprehension, and when cognitive impairment increases (moderate or severe dementia group), the contributing effect of hearing loss as a cognitive ability-impairing factor also increases. Greater understanding of the links between hearing impairment and cognition may have important implications for the screening and diagnosis of cognitive decline in older people with hearing impairment.