An anonymous reader quotes a report from the Washington Post: A study published Monday in the Lancet found that the use of hearing aids can reduce the risk of cognitive decline by about half — 48 percent — for adults with more risk factors for dementia, such as elevated blood pressure, higher rates of diabetes, lower education and income, and those living alone. The study was presented at the Alzheimer’s Association International Conference in Amsterdam. […] Over a three-year period, the randomized controlled trial studied nearly 1,000 older adults, ages 70 to 84, in four sites in the United States. The participants included older adults in an ongoing study of cardiovascular health — Atherosclerosis Risk in Communities (ARIC) — and others who were healthier than the ARIC adults; both groups were from the same communities at each site.
When the two groups were combined, use of hearing aids was shown to have no significant effect on slowing cognitive changes. When the group at higher risk of dementia, the ARIC group, was analyzed separately, however, researchers found that hearing intervention — counseling with an audiologist and use of hearing aids — had a significant impact on reducing cognitive decline. Those considered at high risk for dementia were older and had lower cognitive scores, among other factors. When the groups were combined, the slower rate of cognitive decline experienced by the healthier participants may have limited any effect of hearing aids, the researchers suggested. Whether hearing treatment reduces the risk of developing dementia in the long term is still unknown. “That’s the next big question — and something we can’t answer yet,” said Lin, who is also director of the Cochlear Center for Hearing and Public Health at Johns Hopkins University. He said he and his colleagues are planning a long-term follow-up study to attempt to answer that question.
There have many studies over the past decade to try to determine why people with hearing loss tend to have worse cognition, said Justin S. Golub, an associate professor of otolaryngology at Columbia University Irving Medical Center. One theory is that it requires a lot of effort for people with hearing loss to understand what others are saying — and that necessary brainpower leaves fewer cognitive resources to process the meaning of what was heard, he said. Another theory relates to brain structure. Research has shown that the temporal lobe of people with hearing loss tends to shrink quicker because it is not receiving as much auditory input from the inner ear. The temporal lobe is connected to other parts of the brain, and “that could have cascading influences on brain structure and function,” said Golub, who was not part of the Lancet study. A third theory is that people with hearing loss tend to be less social and, as a result, have less cognitive stimulation, he said.