Most people recognise their dog’s usual way of walking instinctively. We spot the eager trot towards the door and its rhythm along a favourite path.
Yet a change in that gait can be easy to miss. New research into ageing dogs indicates that one subtle difference warrants more attention.
As cognitive ability declines, the length of a dog’s front-leg stride becomes shorter. Cognitive decline appears to have a greater influence than ageing by itself.
Researchers at North Carolina State University monitored 88 senior and older dogs to examine how their movement changed over time.
They recorded the length of every stride and compared it with owner-reported changes in memory and behaviour.
Front legs carry the signal
The front legs revealed a distinct pattern. Dogs with poorer scores on a dementia scale had shorter front-leg strides.
The hind legs showed no equivalent trend. Their stride length remained relatively consistent regardless of cognitive changes.
The study’s lead author, Dr Natasha Olby, is a professor of veterinary neurology and neurosurgery at North Carolina State University.
“Here we show that the length of front leg stride taken by dogs decreases with age, but even more importantly, decreases with a cognitive impairment,” said Dr. Olby.
“In fact, we found that the effect of cognitive decline is larger than the effect of age by itself.”
How the walk was measured
Every dog walked along a five-metre corridor at its natural pace, on a loose lead and without treats or encouragement. The walk was filmed from the side.
Trained observers logged each step made by every leg. They calculated stride length by dividing the walkway distance by the number of steps, then correcting the result for the dog’s shoulder height.
This correction is important, as it removes the simple difference that a Great Dane covers more distance in one step than a Chihuahua.
Two observers assessed the footage and produced closely matching figures. The approach was shown to be readily repeatable.
Cognition counts more than age
Ageing dogs do generally take shorter strides. However, when researchers assessed age and cognition together, age alone was no longer a meaningful factor.
Dementia scores remained associated with stride length after accounting for age. A dog’s cognitive condition, rather than only its age in years, influenced how far its front legs extended.
The effect was small. A 10-point increase on the dementia scale corresponded with an approximately 1.2 percent reduction in front-leg stride length.
Steps represent more than speed
Previous research had linked slower walking in older dogs with cognitive decline. This study examined whether stride length offers information beyond walking speed alone.
When researchers tested step length and walking speed alongside cognitive scores, stride length retained its significance while speed did not.
The distance covered in each step therefore appears to provide a separate signal. Speed by itself does not show the whole picture.
Why front and hind legs differ
The difference between the front and hind legs is biomechanically plausible. Each pair of legs serves distinct functions while a dog is moving.
“It is fascinating to see that cognitive decline affects front legs and hind legs differently. In dogs, the hind legs are important for moving forwards, while the front legs also change direction and initiate braking,” said Olby.
“The cerebral cortex integrates more sensory information into the neuronal circuits which produce steps in the front legs, and so loss of high-level sensorimotor integration affects them differently.”
Hind-leg movement relies more heavily on rhythmic patterns and joint condition. By contrast, front-leg movement requires the brain to combine many signals, precisely the ability that cognitive decline can diminish.
Pain shortens steps as well
Painful joints were also a factor. Dogs with higher pain scores likewise took shorter strides with their front legs.
However, pain did not remove the association with cognition. The relationship between dementia scores and stride length persisted after pain was taken into account.
This suggests there is more than one contributing cause. Both cognitive decline and painful joints can shorten a dog’s strides.
The pattern reflects observations in people. Well before memory problems become clearly apparent, some patients start walking more slowly with shorter, uneven steps.
These changes are linked to brain areas responsible for planning and monitoring movement. Dogs appear to share a similar pattern.
What dog owners can look for
For owners, the practical message is straightforward. A noticeably shorter front-leg stride is a reason to arrange a veterinary appointment.
“If owners notice that their dog’s front leg stride is becoming shorter they should visit their vet, for there are possible alternative causes such as arthritic pain or neck issues that can be treated,” noted Olby.
“If a diagnosis of cognitive decline is made, there are likewise several lifestyle interventions that can be made, even if there is currently no cure.”
Where the method falls short
The research has several limitations. Owners completed questionnaires to assess cognition and pain, rather than the dogs receiving formal diagnoses.
Its design also cannot establish cause and effect. Shorter strides occurred alongside cognitive decline, but the study did not demonstrate that either one causes the other.
Participation was limited to dogs capable of walking the course. The animals most severely affected were therefore probably excluded.
Even so, the method’s appeal lies in its simplicity. It requires only a short walk, a camera and careful step counting.
If monitored over time and considered alongside routine assessments, it could identify a dog beginning to decline before the changes become clear. That potential early warning is its key value.
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