Owner reported sensory impairments affect behavioural signs associated with cognitive decline in dogs

Abstract

To describe the extent of age-related cognitive decline in dogs, information regarding the baseline occurrence of associated behaviours in the general population is necessary. With a seven-item, data driven Age-Related Changes scale, we evaluated the relationship between sensory functions, training, sex, and the occurrence of behavioural signs associated with cognitive decline across the whole adult lifespan. The twofold difference in lifespan between small and large dogs presents challenges for ageing studies, with no widely accepted method to control for body size as it relates to chronological age and longevity, when comparing behavioural signs of cognitive decline. To address this issue, we utilized relative age, calculated using the estimated expected lifespan of the individuals in our questionnaire study. Signs of cognitive decline were already detectable in' Mature' dogs (at 50-75% of the expected lifespan). Visual, auditory and olfactory impairments all resulted in significantly higher scores on the Age-Related Changes scale. Participating in dog training activities was revealed to be protective against behavioural signs of cognitive decline in aged dogs as perceived by the owners. These results revealed possible beneficial effects of training on cognitive ageing and emphasize the importance of routinely screening the sensory capacities of ageing dogs.

Gut Microbiome Composition is Associated with Age and Memory Performance in Pet Dogs

“…The wide range of expected lifespans, a natural risk to develop dementia, and an environment shared with humans, has also made dogs a promising model organism in aging research (for a review see [10]). Since laboratory dogs represent a limited sample of the natural genetic and environmental variability found in human populations and companion (or pet) dogs, the latter has gained more popularity in aging research recently [11][12][13][14][15][16][17][18]. Their behavior also differs from that of laboratory dogs [19] in ways that make the companion dog a more ecologically valid model of human aging.…”

A Preliminary Study toward a Rapid Assessment of Age-Related Behavioral Differences in Family Dogs

“…Finally, they are among the few model animals, alongside cats, that naturally develop dementia-like symptoms [4][5][6].…”

“…Some tests investigating cognitive skills require extensive pre-training before the animals' behavior can be evaluated with the test [10,15]. The administration of test batteries which capture spontaneous behavioral performances can save on both costs, although, like questionnaires, [16] they might not always distinguish clearly between behavioral differences caused by aging of the brain, body, and sensory systems, or be able to determine whether each system is affected [5]. For this reason, in some investigations, dogs were first pre-selected for equal performance based on sensory acuity tasks [15].…”

“…Dogs display many humanlike social behaviors [ 3 ]. Finally, they are among the few model animals, alongside cats, that naturally develop dementia-like symptoms [ 4 , 5 , 6 ].…”

Individual and group level personality change across the lifespan in dogs

“…This is a problem because some studies have revealed that the relationship between age and behaviour is not always linear 22 , 23 , so dog ageing studies which compared only young and aged dogs or analysed the effect of age only with correlations or with linear models, may have led to biased conclusions. Impaired dogs A proportion of aged dogs, especially those considered senior/geriatric could suffer from age-related physical, sensory, or mental impairments which could change their behaviour compared to that of successfully ageing dogs 24 , 25 . Studies assessing behaviours other than cognition rarely make efforts to identify potentially impaired dogs in their sample, even though individuals with severe behavioural deterioration may affect the general age trajectory of a given personality trait.…”