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 ≥ 2 signs of dysfunction within a category.
Dogs with impairment in 1 category were considered
mildly impaired and those with impairment in ≥ 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 all categories. The percentage of
11- to 12-year-old dogs with impairment in ≥ 1 category
was 28% (22/80), of which 10% (8/80) had
impairment in ≥ 2 behavioral categories. Of 15- to 16-
year-old dogs, 68% (23/34) had impairment in ≥ 1 category,
of which 35% (12/34) had impairments in ≥ 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.
(J Am Vet Med Assoc 2001;218:1787–1791)