March 7, 2025
Keio University School of Medicine
A research group led by Senior Lecturer Takatsugu Nishiyama and Associate Professor Naoki Oishi of the Department of Otorhinolaryngology, Head and Neck Surgery at the Keio University School of Medicine, has discovered that in a group of individuals with hearing loss aged 55 and older with no experience using hearing aids, there is a negative correlation between hearing thresholds and cognitive function test results. They found that a risk for dementia could arise when the average of hearing thresholds at four different frequencies exceeds 38.75 dB HL. At the same time, in a group of individuals with hearing loss who had used hearing aids for over three years, the correlation between hearing ability and cognitive function tests disappeared, and no hearing threshold posing a risk for dementia was observed. These findings suggest that using hearing aids may mitigate the risk of dementia associated with hearing loss.
In Japan, a super-aging society, dementia has become a major economic and social issue. It has gained significant attention since hearing loss was reported as the largest modifiable risk factor for dementia in midlife. As the primary cause of hearing loss is aging, hearing aids are currently the main form of treatment. However, it was previously unknown at what level of hearing loss hearing aids should be used for dementia prevention, meaning people could have been living with an unrecognized risk of dementia. The findings of this study, which clarify the hearing level that may pose a risk for dementia, are expected to serve as a new indicator contributing to dementia prevention.
The results of this study were published inNPJ Aging, a partner journal ofNature, on February 24, 2025 (US time).
Please see below for the full press release.