A new study from North Carolina State College discovers the link between hearing loss and dementia in geriatric dogs. The work could aid both in the treatment of aging dogs and in understanding the relationship between sensory loss and cognitive function in dogs.
“In humans, we know that age-related hearing loss affects one-third of people over 65 years,” says Natasha Olby, holder of the Dr. Kady M. Gjessing and Rahna M. Davidson Distinguished Chair in Gerontology in the State of North Carolina. University and corresponding author of the study.
“We also know that the rate of cognitive decline is approximately 30 at 39% faster in people with age-related hearing loss and that hearing loss contributes more to the risk of dementia than to other factors such as hypertension or obesity. But we don’t know. understand if the same is true for dogs.”
In the study, Olby and colleagues assessed 39 senior or geriatric dogs. Auditory and cognitive tests were performed on each dog and their owners were asked to complete two commonly used questionnaires, one focusing on cognitive abilities and the other on quality of life. Cognitive tests, questionnaire scores and age were compared between the hearing groups.
The “average” dog can hear tones at 50 decibels (dB) without difficulty. Among the study cohort, 19 dogs could hear at 50 dB, 12 to 70 dB and eight to 90 dB (roughly equivalent to the noise emitted by a jet aircraft taking off). The average age of the dogs in each group was respectively 12, 13 and 14 years.
When the researchers compared the hearing results along with owners’ responses to the Quality of Life Questionnaire, they found that scores related to vitality and companionship decreased significantly as hearing deteriorated.
Similarly, the scores of the cognitive questionnaire classified the eight dogs of the 90 dB group as abnormal, against nine of the 12 dogs of the group 70 dB and eight of the 19 dogs of the group 39 dB. The results of the cognitive tests were similar: as hearing decreased, the dog’s ability to perform tasks also decreased.
“Hearing loss is one of the strongest predictors of dementia in people,” says Olby. “Hearing loss also contributes to falls in the elderly, as sensory decline contributes to a loss of motor skills. Thus, the link between physical and neurological decline is clear for humans.
“This study indicates that the same connection is at work in aging dogs. But since we can potentially treat hearing loss in dogs, we might be able to alleviate some of these other issues. By quantifying neurological and physiological changes in older dogs, we’re not only improving our ability to identify and treat these issues in our pets, but we’re also creating a model to improve our understanding of the same issues in humans. ”
The study appears in the Journal of Veterinary Inner Medication. Margaret Gruen, assistant professor of behavioral medicine at NC Condition, is co-lead author of the book.