Summary: Researchers have found that hearing loss in older adults is linked to certain brain changes that increase the risk of dementia.
Using hearing tests and MRI, the study identified subtle structural differences in brain regions responsible for hearing, speech and executive functions in people with hearing loss. Chief Investigator Linda K. McAvoy emphasizes that these changes may stem from the cognitive effort required to process sounds.
The study emphasized the importance of hearing and early interventions to prevent dementia.
- Hearing loss in the elderly is associated with changes in brain areas involved in sound processing and executive functions, which may increase the risk of dementia.
- The research suggests that the cognitive strain involved in understanding sounds may contribute to these brain changes, highlighting the importance of interventions such as hearing aids and quiet environments.
- This research is part of a long-term study (the Rancho Bernardo Study of Healthy Aging) and was funded by several institutions, including the National Institute on Aging and the American Federation for Research on Aging.
Hearing loss affects more than 60 percent of adults 70 and older in the United States and is associated with an increased risk of dementia. The reason for this association is not fully understood.
To better understand the connection, researchers from the University of California San Diego and the Kaiser Permanente Washington Institute for Health Research used hearing tests and magnetic resonance imaging (MRI) to determine whether hearing loss is linked to differences in specific brain regions.
Issued on November 21, 2023 Journal of Alzheimer’s DiseaseIn this observational study, researchers reported that individuals with hearing loss showed subtle structural differences in the auditory part of the temporal lobe and the areas of the frontal cortex involved in speech and language processing.
“These results suggest that hearing loss causes changes in brain areas involved in processing sounds as well as in brain areas involved in attention. The extra effort involved in trying to understand sounds may lead to significant changes in the brain’s susceptibility to dementia,” said principal investigator Linda K., professor emeritus and Senior Investigator at Kaiser Permanente Washington Health Research Institute.
“If so, interventions to reduce the cognitive effort required to understand speech—such as using subtitles on television and movies, live captions or speech-to-text applications, hearing aids, and timed visits with people in quiet, non-noise environments—may protect the brain and reduce the risk of forgetfulness. It may be necessary to reduce.”
While at UC San Diego, McEvoy led the study in collaboration with Reiss and UC San Diego School of Medicine investigators who collected data from the Rancho Bernardo Study of Healthy Aging, a longitudinal cohort study of residents of the Rancho Bernardo suburb of San Diego. In the year Started in 1972. For this analysis, 130 study participants underwent a hearing test at research clinic visits between 2003 and 2005 and then underwent an MRI scan between 2014 and 2016.
The results of the study show that hearing impairment is associated with regionally specific brain changes that can be caused by sensory stimuli and the high effort required to understand auditory stimuli.
“The findings highlight the importance of protecting hearing by avoiding long-term exposure to loud noises, wearing hearing protectors and wearing noise protectors, and reducing the use of ototoxic medications,” said Associate Professor Emily T. Race, Ph.D. at the UC San Diego School of Medicine.
Co-authors include: Jaclyn Bergstrom, Donald J. Hagler Jr, David Wing and Emilie T. Reas, all of UC San Diego.
Financial support This research was funded in part by the National Institute on Aging (R00AG057797, R01AG077202, R01AA021187) and the American Federation for Aging Research/McKnight Foundation (311122-00001). Data collection for the Rancho Bernardo Healthy Aging Study was primarily provided by the National Institutes of Health (HV012160, AA021187, AG028507, AG007181, DK31801, HL034591, HS06726, HL089622). Archiving and sharing of Rancho Bernardo study data was supported by the National Institute on Aging (AG054067). Information is available from the study website at: knit.ucsd.edu/ranchobernardostudy/.
Disclosures: Donald J. Hager Jr. is listed as an inventor on US Patent 9,568,580, 2017 “Identification of White Matter Fiber Tracts Using Magnetic Resonance Imaging (MRI)”. Other authors reported no conflict of interest.
So hearing loss and dementia research news
Author: Yadira Galindo
Contact: Yadira Galindo – UCSD
Image: Image credited to Neuroscience News.
Preliminary study: Open Access.
“Elevated pure-tone thresholds are associated with altered microstructure in cortical areas associated with auditory processing and attentional allocation.” by Linda K. McEvoy et al Journal of Alzheimer’s Disease
Elevated pure-tone thresholds are associated with altered microstructure in cortical areas associated with auditory processing and attentional allocation.
Hearing loss is associated with cognitive decline and an increased risk of Alzheimer’s disease, but the basis of this association is not understood.
To determine whether hearing loss is related to advanced brain aging or altered microstructure in areas involving hearing and cognitive processing.
130 participants, (mean 76.4±7.3 years, 65% women) of the Rancho Bernardo Healthy Aging Study had a screening audiogram in 2003–2005 and a brain magnetic resonance imaging in 2014–2016. Hearing ability was defined as the average pure tone threshold (PTA) at 500, 1000, 2000 and 4000 Hz in the best hearing. Brain-estimated age difference (Brain-pad) The difference between brain-estimated age is calculated based on validated brain age biomarkers and chronology. Regional diffusion parameters in temporal and frontal cortex regions were obtained from diffusion-weighted MRIs. Linear regression adjusted for age, gender, education, and health-related measures.
PTAs were not associated with brain-PAD (β= 0.09; 95% CI: -0.084 to 0.243; p = 0.34). PTAs decreased restricted diffusion and increased free water diffusion primarily in right hemisphere temporal and frontal areas (restricted diffusion: βs = −0.21 to −0.30; 95% CIs −0.48 to −0.02; ps < 0.03; free water: βs = 0.18 to −0.30). 0.26; 95% CIs 0.01 to 0.438; ps < 0.04).
Hearing loss is not associated with advanced brain aging, but with differences in brain regions involved in controlling hearing and attention. Thus, the dementia associated with hearing loss may be partly due to compensatory brain resistance to changes.