Prevalence of behavioral changes associated with age-related cognitive impairment in dogs

Objective-To determine the prevalence of age-related behavioral changes, namely impairment, in a randomly chosen population of dogs. Design-Age-stratified cohort study. Animals-97 spayed female and 83 castrated male dogs that were 11 to 16 years old. Procedure-Data on possible impairment in 4 behavioral categories (ie, orientation in the home and yard, social interaction, house training, and sleep-wake cycle) linked to cognitive dysfunction were obtained from dog owners, using a structured telephone interview. Hospital records of dogs had been screened to exclude dogs with dysfunction in organ systems that may cause behavioral changes. Dogs with behavioral impairment were those with greater than or equal to 2 signs of dysfunction within a category. Dogs with impairment in 1 category were considered mildly impaired and those with impairment in greater than or equal to 2 categories were considered severely impaired. Results-Age by sex interactions for dogs with impairment in any category were not significant, and, therefore, data on castrated males and spayed females were pooled for analyses across ages. The prevalence of age-related progressive impairment was significant in ail categories. The percentage of 11- to 12-year-old dogs with impairment in greater than or equal to 1 category was 28% (22/80), of which 10% (8/80) had impairment in greater than or equal to 2 behavioral categories. Of 15-to 16-year-old dogs, 68% (23/34) had impairment in greater than or equal to 1 category, of which 35% (12/34) had impairments in greater than or equal to 2 categories. There were no significant effects of body weight on the prevalence of signs of dysfunction in the behavioral categories. Conclusions and Clinical Relevance-Data collected provide estimates of the prevalence of various degrees of age-related behavioral changes associated with cognitive dysfunction in dogs. Age-related behavioral changes may be useful indicators for medical intervention for dogs with signs of cognitive impairment.