Does the Future Hold Better Hearing Options for Aging Dogs?

Approximately one-third of individuals older than age 65 experience presbycusis. The serious consequences of age-related untreated hearing loss due to presbycusis include a faster rate of cognitive decline, a higher risk for dementia, social isolation depression, and ultimately, a decreased quality of life (QoL) (Chen et al, 2018).

Presbycusis is also a common phenomenon in the aging process of dogs, starting at approximately 8­–10 years of age. (Ter Haar et al, 2008). However, the consequences of presbycusis in companion animals and their QoL have not been well studied.

Fefer and colleagues (2022) evaluated the relationships among aging, cognitive function, QoL and hearing loss in old companion dogs. The authors hypothesized that, as hearing declines in dogs, there would be a decline in cognitive performance as well as QoL according to the owners’ assessment.

Thirty-nine dogs with a median age of 13 years were evaluated via brainstem auditory evoked responses (BAER) to establish hearing. Cognitive testing was completed by a dog handler for all dogs, and a QoL assessment (The CORQ—Canine Owner-Reported Quality of Life) was completed by the dogs’ owners. Owners also completed a canine cognitive dysfunction assessment (Canine Dementia Scale—CADES) for their dog.

Results revealed significantly lower vitality and companionship domains for the dogs with hearing loss relative to those without hearing loss. These findings suggest that the quality of interactions between dogs and their owners decline as a dog’s hearing declines. This change in perceived QoL is similar to findings for people with presbycusis. The data also revealed an association between hearing loss and severity of cognitive dysfunction as scored by owners, including poorer performance on certain cognitive tests of executive function.

Research has shown that the use of hearing aids and cochlear implants can counteract the progression of presbycusis and help mitigate many of the changes seen with cognitive decline and depression in the elderly (human) population. This is not currently feasible with dogs, as amplification is not well tolerated.

However, the authors are hopeful there will be well-tolerated and affordable hearing aids for dogs in the near future, and conclude that the relationships among presbycusis, aging and dementia deserve further investigation in dogs.

References

Chen Y, Ye B, Chen P, et al. (2018) Cognitive decline, dementia, Alzheimer’s disease and presbycusis: examination of the possible molecular mechanism. Front Neurosci 12:1–14.

Fefer G, Khan MZ, Panek WK, Case B, Gruen ME, Olby NJ. (2022) Relationship between hearing, cognitive function, and quality of life in aging companion dogs. J Vet Intern Med 2022:1–11.

Ter Haar G, Venker-van Haagen AJ, van den Brom WE, et al. (2008) Effects of aging on brainstem responses to tone burst auditory stimuli: a cross-sectional and longitudinal study in dogs. J Vet Intern Med 22:937–945.