Examining ear with otoscope

Understanding the importance of hearing loss for those with Alzheimer’s disease and their caregivers

By: Marilyn Reed, professional practice leader for audiology at Baycrest Health Sciences

The link between age-related hearing loss and cognitive impairment has been well established through over 30 years of research, and recent exciting findings have caused a resurgence of interest in this relationship.

When functioning optimally, auditory and cognitive processing together enable us to receive and perceive multiple acoustic signals superimposed upon each other (such as when we are listening to conversation in a noisy restaurant) so that we can extract meaning from the cacophony of sounds around us almost effortlessly.

The interaction and codependence of cognition and sensory systems allows us to perceive the world around us, to comprehend, communicate, to learn, and to share thoughts and ideas. Our ears enable us to hear, but our brains enable us to use what we have heard for specific purposes.

Impairments of hearing and cognition both increase markedly with age such that the majority of those over 75 years of age have hearing loss and about 1/5 have cognitive impairment. Since both hearing and cognitive impairment are highly prevalent in older adults, it is reasonable to expect that dual impairments would be common. However, these conditions seem to combine in ways that we are only beginning to understand. Hearing loss is more prevalent in those with dementia (9/10 cases) and recent studies of those with mild cognitive impairment (MCI) have found that their performance on tests of auditory processing is worse than that of controls. In addition, epidemiological studies have shown that hearing loss and the ability to understand speech in noise are predictive of the future manifestation of dementia.

Audiologists, psychologists, neuroscientists and others (including those at Baycrest) are exploring the interactions between sensory and cognitive processes in healthy aging and in those with dual impairments, and what we learn should have a positive impact on patient care.

Because research has provided strong evidence that hearing impairment contributes to or accelerates the progression of symptoms of cognitive decline in older adults, hearing health care is an important component in the larger context of healthy aging.

Studies have also shown that the use of interventions such as hearing aids can help individuals with Alzheimer’s disease, and yet these individuals are much less likely to receive attention for their hearing needs. As well as helping patients hear better, we can also help to alleviate the burden of caregivers by reducing problem behaviors and facilitating communication.

A comprehensive hearing assessment should be part of any Alzheimer’s diagnosis because interventions for hearing loss might not only help to maintain social interaction but might also help to stave off or slow down the manifestation of symptoms of dementia. 

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