Peripheral Hearing Loss at Age 70 Predicts Brain Atrophy and Associated Cognitive Change
Age-related hearing loss is considered a modifiable risk factor for dementia. However, the relationship between hearing, neurodegenerative changes, and cognitive changes, as well as how pathological processes such as Alzheimer’s disease and cerebrovascular disease affect these relationships, is not yet well understood. This report details a study on the relationship between hearing loss in older adults and brain and cognitive changes.
Researchers and Source:
The study was conducted by Thomas D. Parker, Chris Hardy, and others, from multiple institutions including University College London. The research results were published in the 2024 issue of the Journal of Neurology, Neurosurgery and Psychiatry.
Research Methods and Procedure:
1) A total of 287 older adults, all born in the same week of 1946 with an average age of 70.6 years, were included. They underwent baseline pure tone audiometry and two cognitive assessments/multimodal brain imaging sessions spaced an average of 2.4 years apart. 2) Baseline hearing was assessed using pure tone average (PTA), with PTA > 25dB defined as hearing loss. 3) Structural MRI data were collected, and boundary shift integral (BSI) was used to estimate the rate of volume change in the whole brain, hippocampus, and ventricles. 4) Cognitive function was assessed using the Preclinical Alzheimer’s Cognitive Composite (PACC). 5) Regression model analyses were conducted to evaluate how baseline hearing loss related to subsequent brain atrophy and cognitive decline, controlling for potential confounders such as baseline amyloid deposition and white matter hyperintensity volume.
Main Results:
1) 111 out of 287 participants had hearing loss. 2) Compared to those with preserved hearing, participants with hearing loss exhibited faster whole-brain atrophy rates; worse hearing (higher PTA) was associated with faster hippocampal atrophy rates. 3) Among those with hearing loss, faster whole-brain atrophy rates correlated with greater cognitive changes. 4) These relationships were independent of amyloid deposition and white matter hyperintensity volume.
Significance of the Study:
1) Hearing loss may influence dementia risk through pathways distinct from Alzheimer’s disease and cerebrovascular disease. 2) The results suggest a complex interplay between hearing, neurodegenerative changes, and cognitive function. 3) Future research with larger sample sizes, longer follow-up periods, and more detailed biomarker characterization is needed for deeper exploration.
Features of the Study:
1) Unique age-matched sample population. 2) Detailed longitudinal phenotypic data. 3) Exploration of the impact of hearing loss independent of Alzheimer’s disease and cerebrovascular pathways.