Hearing Loss and Cognitive Decline in Older Adults
Lin and colleagues (2013) report a prospective, observational study that started in 1997/1998. The original study (Health, Aging and Body Composition, "HealthABC") involved more than 3,075 people, aged 70 to 79 years. Each participant lived within a one hour drive of the test facility in either Pittsburgh, Pennsylvania, or Memphis, Tennessee. Each participant was able to walk a quarter mile, climb 10 steps without resting and could perform basic activities of daily living. Of the 3,075 people 2,206 participants had hearing tests and of those, 1,984 participants had no evidence of cognitive impairment.
Specifically, 1,984 participants had baseline Modified Mini Mental State Examination (3MS, a global cognitive function scale) scores greater than or equal to 80, indicating they did not have prevalent cognitive impairment when they entered the study (follow-up testing included the 3MS and the Digit Symbol Substitution [DSS] test, a measure of executive function). Of the 1,984 adults without evidence of cognitive impairment, 1,162 adults had baseline hearing tests available indicating pure-tone averages greater than 25 dB (based on the better ear, from 500 to 4000 Hz).
The authors report that annual rates of decline in 3MS and DSS were 41 percent and 32 percent greater (respectively) for those with hearing loss, than for those with normal hearing. Lin and colleagues note "Rates of cognitive decline and the risk for incident cognitive impairment were linearly associated with the severity of an individual’s baseline hearing loss." Importantly, they further concluded hearing loss is indeed independently associated with accelerated cognitive decline and is associated with incident cognitive impairment in community dwelling older adults. However, they clearly state further studies are required before one can say whether or not hearing rehabilitative interventions are able to impact cognitive decline.
For More Information, References, and Recommendations
Lin FR, Yaffe K, Xia J, Xue QL, Harris TB, Purchase-Helzner E, Satterfield S, Ayonayon HN, Ferrussi L, Simonsick EM. (2013) Hearing Loss and Cognitive Decline in Older Adults. JAMA, Intern Med 173(4):293-299.