Doctors of Audiology | Board Certified Audiologists
The Link Between Hearing Loss and Dementia
The road ahead can be a hazardous trip for those unwilling to pay attention to the signs…
A ground-breaking study indicates that people who experience significant hearing loss as they age may also be at higher risk of developing dementia. The study was conducted by researchers at Johns Hopkins University School of Medicine in Baltimore in partnership with the National Institute on Aging. Dr. Frank Lin and others found that older adults with hearing loss were more likely to develop cognitive decline over time than others who didn’t experience hearing loss as they aged. Cognitive function is an intellectual process that allows us to become aware of, perceive, or comprehend ideas. It involves all aspects of perception, thinking, reasoning, and remembering. While hearing loss is not a “sentence” of creeping dementia, the study found that people with severe hearing loss were five times more likely to develop cognitive problems. A disturbing finding of the study indicates that even mild hearing loss doubles the risk for serious cognitive impairment. Dr. Frank Lin, an assistant professor of otolaryngology and epidemiology at Johns Hopkins, directed the study: “For many years, hearing loss in older adults has been perceived as an unfortunate but inconsequential part of aging. Our research is now demonstrating that hearing loss doesn’t just affect a person’s quality of life. It may also lead to a decline in cognitive function.” Dr. Lin believes that the neurological stress imposed by hearing loss, such as the constant effort required to decode conversations, may ultimately take its toll. “We also know that people with hearing loss tend to avoid socializing,” he says, “and that social isolation is a risk factor for dementia.” The good news is that social isolation and the risk of dementia can be greatly diminished or even eliminated through proper treatment. Hearing aids fit and programmed to your individual hearing loss profile can provide auditory stimulation, which not only allows you to communicate effectively, but may also contribute to delaying or even preventing diseases like dementia.
Hearing Loss and Incident Dementia
Frank R. Lin, MD, PhD; E. Jeffrey Metter, MD; Richard J. O’Brien, MD, PhD; Susan M. Resnick, PhD; Alan B. Zonderman, PhD; Luigi Ferrucci, MD, PhD
Objective: To determine whether hearing loss is associated with incident all-cause dementia and Alzheimer disease (AD). Design: Prospective study of 639 individuals who underwent audiometric testing and were dementia free in 1990 to 1994. Hearing loss was defined by a pure-tone average of hearing thresholds at 0.5, 1, 2, and 4 kHz in the better-hearing ear (normal, <25 dB [n = 455]; mild loss, 25-40 dB [n = 125]; moderate loss, 41-70 dB [n = 53]; and severe loss, >70 dB [n = 6]). Diagnosis of incident dementia was made by consensus diagnostic conference. Cox proportional hazards models were used to model time to incident dementia according to severity of hearing loss and were adjusted for age, sex, race, education, diabetes mellitus, smoking, and hypertension. Setting:Baltimore Longitudinal Study of Aging. Participants: Six hundred thirty-nine individuals aged 36 to 90 years. Main Outcome Measure: Incident cases of all-cause dementia and AD until May 31, 2008. Results: During a median follow-up of 11.9 years, 58 cases of incident all-cause dementia were diagnosed, of which 37 cases were AD. The risk of incident all-cause dementia increased log linearly with the severity of baseline hearing loss (1.27 per 10-dB loss; 95% confidence interval, 1.06-1.50). Compared with normal hearing, the hazard ratio (95% confidence interval) for incident all-cause dementia was 1.89 (1.00-3.58) for mild hearing loss, 3.00 (1.43-6.30) for moderate hearing loss, and 4.94 (1.09-22.40) for severe hearing loss. The risk of incident AD also increased with baseline hearing loss (1.20 per 10 dB of hearing loss) but with a wider confidence interval (0.94-1.53). Conclusions: Hearing loss is independently associated with incident all-cause dementia. Whether hearing loss is a marker for early-stage dementia or is actually a modifiable risk factor for dementia deserves further study.