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Hearing, Vision Impairments May Contribute to Increasing Dementia

Duke geriatrician leads workshop engaging national experts in age-related research

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Recommendations to reduce hearing and vision impairments and determine how they may contribute to rising dementia in the United States have been issued by national experts in sensory decline led by Duke geriatrician Heather E. Whitson, MD, MHS, principal investigator and co-chair of the initiative.

The conference report issued by the researchers emphasized vision and hearing interventions for senior patients and encouraged further research into biological mechanisms or genetic and behavioral factors that may link poor vision and hearing to risk of dementia. The conference was sponsored by the American Geriatrics Society and the National Institute on Aging.

Considering that almost 15 percent of individuals age 70 or older have dementia, researchers want to identify interventions to prevent dementia or reduce its symptoms of memory loss and other problems with thinking, says Whitson, who is deputy director of the Duke University Aging Center.

"It’s very clear in epidemiological data that people with sensory impairments such as vision or hearing loss are more likely to have cognitive deficits and dementia,” Whitson says. “But these researchers recognized that it’s too easy to jump to the conclusion that sensory loss causes dementia.”

Invited selectively from a range of disciplines, the investigators encouraged further exploration of the mechanism or mechanisms that link age-related sensory loss to cognitive decline. The panel posed other questions about the relationship between  sensory loss and cognition:

  • Does the brain undergo changes as a direct result of late-life impairments in vision and hearing? How are thought processes challenged when sensory input is reduced?
  • Do some people have risk factors that make them more likely to develop problems concurrently in their abilities to see, hear, and think?

“Sorting out whether both or one of those is truer is important because it would determine how we should go about trying to promote cognitive and sensory health as people age,” Whitson says.

The expert panel agreed that hearing and vision interventions are effective, but should be undertaken more frequently. Hearing aids or cochlear implants are commonly recommended for the hearing impaired; updated lenses or cataract surgery can have a dramatic effect on vision.

“Just trying to help people see and hear better is a significant and essential intervention,” Whitson says. “With vision and hearing, we recognize that better and earlier detection through regular check-ups should be encouraged.” Additional research is needed to determine whether improving vision and hearing ability may have a bonus effect of protecting cognition, she adds.

Another tactical issue, Whitson notes, is the need for consistent cognitive testing. “Everyone recognizes that we need better measures for detecting cognitive decline, especially in people who can’t see or hear well.” Beyond the common interventions, however, Whitson says the researchers also explored genetic issues and potential pharmaceutical development opportunities.

“If a significant risk factor connecting these two problems—a genetic cause, for example—could be identified that makes a patient susceptible to neurological degenerative problems in the eyes and the brain, the researchers believe that this would become a pharmacological priority,” Whitson says.