New research from North Carolina State University shows cognitive decline in dogs is associated with a shorter stride length – specifically in their front limbs. The work provides a more complete picture of dogs that are developing dementia, potentially allowing earlier detection and providing another means of monitoring progress.
“We know that in humans, changes in stride length have been linked to cognitive impairment and dementia,” says Natasha Olby, professor of neurology and the Dr. Kady M. Gjessing and Rhanna M. Davidson Distinguished Chair in Gerontology at NC State’s College of Veterinary Medicine.
“That relationship hasn’t been investigated in dogs, so we created this study to examine the problem.” Olby is the corresponding author of the research.
The researchers enrolled 88 geriatric dogs with an average age of about 12 years in the study. Dogs were evaluated approximately every six months, undergoing physical, neurologic, and orthopedic examinations, mobility assessments, hearing testing, and blood work. The dogs completed a standardized cognitive test, and owners were asked to complete several questionnaires at each six-month time point, including the Canine Dementia Scale (CADES), and Canine Brief Pain Inventory (CBPI).
Gait speed was assessed by two trained observers as the dogs walked a straight, five-meter indoor walkway. Stride length was measured for both front (thoracic) and back (pelvic) limbs, then data for front limb, back limb and height-adjusted stride length were generated.
The researchers found that owner-reported cognitive decline was associated with shorter thoracic limb stride length, adjusted for height. Higher CADES scores were also associated with reduced stride length, even after adjusting for age and CBPI scores.
A 10-point increase in CADES corresponded to an approximate 1.2% reduction in thoracic limb stride length. Interestingly, pelvic limb stride length did not correlate with cognitive changes.
“While thoracic limbs play a key role in braking and postural stabilization, pelvic limbs mainly act as a propulsion motor,” Olby says. “Thoracic limb movement is likely under more cortical influence than pelvic limbs and may be more sensitive to alterations in visual or spatial awareness than pelvic limb movement.”
The researchers add that while stride length alone isn’t sufficient as a diagnostic tool, it is useful in creating a larger picture of a dog’s cognitive status.
“Our results show that cognitive decline does have a small effect on stride length and this could serve as an early indicator of functional decline in aging dogs,” Olby says. “It could also serve as a useful marker of an individual dog’s overall health trajectory when it is monitored over time.”
The paper, “Thoracic limb stride length is associated with cognitive impairment in aging dogs,” appears in Frontiers in Veterinary Science and was supported by the Dr. Kady M. Gjessing and Rhanna M. Davidson Distinguished Chair of Gerontology at NC State’s College of Veterinary Medicine. The study was led by postdoctoral researcher Shaghayegh Rafatpanah Baigi. Other NC State contributors include veterinary students Akiya Stywall and Katherine E Simon; former postdoctoral researchers Alejandra Mondino Vero, Chin Chieh Yang, and Wojciech K. Panek; Dr. Gilad Fefer; research technician Beth C. Case; and Professor of Clinical Sciences Margaret E. Gruen.
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