Thoracic limb stride length is associated with cognitive impairment in aging dogs.

Introduction: Changes in stride length have been linked to cognitive impairment in humans with dementia. In aging dogs, cognitive decline is accompanied by slower gait speed. However, the relationship between stride length and cognitive decline has not been investigated. This study examined whether height-adjusted stride length is associated with owner-reported cognitive impairment in aging companion dogs. Methods: Data were collected from a cohort of client-owned senior and geriatric pet dogs, enrolled in the Longitudinal Study of Canine Neuroaging. On-leash gait was recorded on a standardized 5 m walkway, and stride lengths were derived from video analysis and normalized to withers height. Cognitive function was assessed using the Canine Dementia Scale (CADES), and pain was evaluated using the Canine Brief Pain Inventory (CBPI). Associations between height-adjusted stride length, age, CADES, and CBPI scores were examined using linear mixed-effects models. Results: Eighty-eight dogs were enrolled. Height adjustment reduced the influence of body size on stride length. Thoracic limb height-adjusted stride length decreased significantly with age, whereas pelvic limb stride showed no significant age-related association. Although CADES scores increased with age, their association with stride length persisted after adjustment for age and pain, while age alone was not a significant predictor in the multivariable model. Intra-observer and interobserver reliability for stride length measurements were excellent. Conclusion: These findings support the use of thoracic limb stride length as an objective, scalable functional mobility measure that reflects changes associated with cognitive decline and may be a useful tool for research and clinical monitoring of aging in dogs.