Cognitive Decline and Untreated Hearing Loss
Communication difficulties are one of the earliest signs of dementia. Hearing loss is the third most prevalent chronic health condition facing older adults. In 2010, 4.7 million people in the Unites States older than 65 had the most common form of dementia, Alzheimer’s disease. In 2016 that number grew to 5.4 million: and in 2050, 13.8 million Americans are expected to have Alzheimer’s. (Herbert, 2013).
The Baltimore Longitudinal Study of Aging (BLSA) found that the severity of hearing loss has a significant positive correlation with the risk of developing dementia. Individuals with severe hearing loss were five times more likely to develop dementia (Deal, 2015).
The National Health and Nutrition Examination Survey (NHANES) showed a much higher incidence of cognitive decline with hearing loss than with aging alone. John Hopkins University found that adults with untreated hearing loss developed cognitive impairment 3.2 years sooner than the normal hearing cohort; and that the rate of cognitive decline was 30-40 percent faster in individuals with hearing loss than in individuals with normal hearing (Lin et al, 2011, 2013).
There is evidence that brain changes occur with sensory deprivation. The University of Colorado concluded that adults with mild hearing loss, many of whom were not even aware of their hearing loss at the time they were enrolled in the study, showed that changes in the auditory cortex lead to functional changes in speech perception and can negatively impact cognitive reserve for working memory and executive functions which contributes to cognitive decline (Campbell and Sharma, 2013, 2014).
Over a 20 year period the Atherosclerosis Risk in Communities (ARIC) conducted a study addressing the hypothesis that older aged persons with hearing loss who use hearing aids have slower rates of cognitive decline than their cohorts who do not wear hearing aids. The study revealed the greatest decline was noted in the cohort who did not use hearing aids. Persons with hearing loss who used hearing aids showed global cognitive decline much more in line with the decline in persons with normal hearing (Deal et al, 2015).
Evidence consistently supports participating in cognitively-stimulating environments as an intervention for management of dementia and hearing aids allow cognitive and interpersonal stimulation and engagement. Properly fitted quality hearing instruments decrease listening effort, allowing patients to feel less exhausted after socializing, allowing more energy for further engagement with family and friends. Well-fit hearing aids allow for cognitively-engaging behaviors, which are known to prevent, delay, or slow cognitive decline.
We know there are positive correlations between severity of hearing loss and the incidence of cognitive decline, severity of cognitive decline and rate of cognitive decline. Cognitive and social engagements that hearing aids allow are known to be protective against cognitive decline. Hearing aids reduce depressive symptoms, boost social engagement and reduce caregiver burden; all of which are critical factors for positive health outcomes and improved quality of life.
Excerpted & Adapted
Studivant, G. 2016 Cognitive Decline + Hearing Loss. Audiology Today. 28 (5):16-21.