Researchers examine links to cognitive decline in hearing loss, military service, and speed of diagnosis


Newswise – As research on dementia accelerates, more and more published articles offer new insights into the disease that impairs memory loss and judgment. Below is a summary of three recent studies involving researchers at UW Medicine. Each included a cohort of volunteers from Kaiser Permanente Washington’s Adult Changes in Thought research program.

Risk of dementia and hearing: The Lancet Commission’s 2020 report suggests that hearing may be particularly important to study in terms of dementia risk. A study published on October 13 in JAMA Otorhinolaryngology suggests that central auditory processing – or how the brain processes sound – might provide additional information.

In an observational study of 280 elderly people without dementia, researchers found that people with intermediate and poor results on dichotic tests (both ears) were at significantly increased risk of developing dementia. Dichotic tests measure certain aspects of central auditory processing.

Sound perception can be tested with standard audiological tests, where beeps at different frequencies are presented at different volumes to determine sound perception thresholds. Once the speech is perceived, it must be transformed by the brain into language.

This study administered two types of hearing assessments: standard audiology threshold tests as well as dichotic tests.

In one of the dichotic tests, noise is presented to one ear and a number is presented to the other ear; the participant is prompted to say the name of the number. Dichotic tests assess the brain’s ability to handle competing auditory signals and to isolate speech against noise.

“The result of our publication is a step in the right direction to better understand the risks of Alzheimer’s disease and to improve our ability to detect the first signs of neurodegenerative disease,” said lead author Adeeb Mohammed, a student at UW’s first cycle in neuroscience and biochemistry.

Co-lead author Paul Crane, a professor of medicine at the University of Washington School of Medicine and principal investigator of the Adult Changes in Thought research program at UW, said this study suggests that further research on the relationship between hearing and dementia risk should be considered. add dichotic tests as part of the measurement.

“Hearing is more complicated than you think,” he said.

An important underlying scientific question is what aspect of hearing loss is associated with dementia, said co-lead author Eric Larson, senior investigator in the Adult Changes in Thought research program at the Kaiser Permanente Washington Health Research Institute.

Larson said George Gates, professor emeritus of otolaryngology at UW Medicine, was a pioneer in early research linking dementia to a decline in central auditory processing in midlife.

“This document is a testament to his work,” he said.

Donor: National Institute of Aging

Military service and dementia: As the number of U.S. veterans over 65 has increased, researchers want to know if military service is associated with an increased risk of cognitive decline.

In a study published in Military medicine On October 9, researchers studied 4,370 participants and found no such link. Researchers classified people as having military jobs if their first or second longest job was with the military. Of the participants, 6% had a military job; of these, 76% were men.

“While our study does not suggest any overall increased risk for those employed in the military, we still need to better understand how specific experiences unique to our veterans may impact the risk of cognitive decline and dementia,” said lead author Dr Melinda Power, associate. professor of epidemiology at George Washington University Milken Institute School of Public Health.

She said veterans can benefit from the same advice given to the general population: stay active, eat well, and actively manage your chronic illnesses.

“Heart health is especially important because what’s good for your heart appears to be good for your brain,” Power said.

Co-authors of UW Medicine: Eric Larson, Department of Medicine and Kaiser Permanente Washington Health Research Institute; Paul Crane, Department of Medicine, Laura Gibbons, Department of Medicine.
Funder: Department of Defense Peer-Reviewed Alzheimer’s Research Program, award number W81XWH-17-1-0330.

Timely diagnosis of dementia: What types of people have access to a rapid diagnosis of dementia or mild cognitive impairment?

In an observational study published in the Journal of General Internal Medicine On October 13, researchers examined 4,760 participants with dementia and 1,864 participants with mild cognitive impairment. They found that only 26% of people with dementia and only 11.4% of people with mild cognitive impairment were diagnosed in a timely manner.

Black non-Hispanic respondents and respondents without a college degree were significantly less likely to receive a timely diagnosis than non-Hispanic white respondents with a college degree. Respondents who lived alone were also less likely to be diagnosed early with dementia, but not with mild cognitive impairment. The diagnosis of both conditions increased over time.

The researchers concluded that targeting resources for a rapid diagnosis of cognitive impairment on people from racial and ethnic minorities or with lower levels of education, and on those living alone, can improve detection and reduce disparities in getting a quick diagnosis of dementia and mild cognitive impairment.

Principal Author: Lindsey White, PhD, with RTI International in Seattle
UW Medicine Co-Authors: Eric Larson, Department of Medicine and Kaiser Permanente Washington Health Research Institute
Donor: National Institute of Aging


Comments are closed.