Hearing loss is a risk factor for cognitive decline that’s independent of other dementia risk factors, according to a new report.
A new study out Jan. 18 in Alzheimer’s & Dementia examined the link between prevalent and incident hearing loss, and cognitive change.
The trial involved 1,823 people between 24 and 82 years old. The participants were assessed at the start of the program, at six years and at 12 years. Participants were put into three groups: No hearing loss, hearing loss with hearing aid use, and hearing loss without using hearing aids.
The researchers found that people with prevalent and incident hearing loss had faster deterioration of verbal memory, information processing speed and executive function compared to people without hearing loss. The decline was steady throughout the study for prevalent hearing loss, but delayed from six to 12 years for incident hearing loss.
The researchers say their work supports the theory that hearing loss is a risk factor for cognitive decline even if an individual doesn’t show other dementia risk factors.
None of the models showed that wearing a hearing aid helped change the link between people with prevalent hearing loss and cognitive decline, whether under the age of 65 or over the age of 65.
A few mechanisms could be behind the link between hearing loss and cognitive decline. Vascular changes or Alzheimer’s disease that affects brain regions could affect the same parts for hearing and cognition. Neurodegeneration could be another factor, though they think that’s less plausible. Hearing loss could impact cognition because of impaired sensory input that changes the brain’s functional connectivity and lowers grey matter volume. Another theory: People with hearing loss use a lot of their neural activity to compensate for the loss at the expense of other brain functions.
“Our findings encourage randomized controlled trials to examine the effect of hearing aid use on cognitive functioning and inform about causality of associations,” the authors wrote. “Increasing awareness and promoting accessibility and use of hearing aids may have important public health implications.”
