The Earliest Signs of Cognitive Decline May Not Be Cognitive

One of the biggest challenges in cognitive decline is that by the time memory symptoms appear, the disease process has often been unfolding for years.

This is one of the central lessons from our movement. Cognitive decline does not begin when someone forgets a name, misses an appointment, or gets lost driving home. Those symptoms are often the final stage of a process that has been quietly developing for a decade or more.

That is why I am always interested in early signals.

A fascinating study published in Alzheimer’s & Dementia in 2022 followed 287 adults for 15 years. All participants had normal cognition when the study began. Researchers measured their walking speed over time and tracked who eventually developed cognitive decline.

The results were striking.

The people who later developed dementia were already walking more slowly up to nine years before their first cognitive symptoms appeared. Their slower gait was also associated with the biological changes seen in Alzheimer’s disease, suggesting that the disease process was already developing while they still appeared completely healthy.

A second study using data from the UK Biobank examined more than 47,000 adults and found something similar. Across the entire dataset, slower walking speed emerged as the strongest gait-related predictor of future dementia.

These studies are observational, so they do not prove that slower walking causes dementia. But they do reinforce an important idea that is becoming increasingly difficult to ignore.

The brain often reveals its struggles through movement long before it reveals them through memory.

Walking may seem simple, but it is actually one of the most complex things we do. Every step requires coordination between multiple brain networks. Balance, attention, sensory processing, motor planning, visual input, and executive function must all work together seamlessly.

When those networks begin to lose efficiency, the first sign may not be a forgotten word. It may be a slower pace.

Reduced arm swing. A slight hesitation when turning. A loss of fluidity. A subtle change that would be easy to dismiss as normal aging.

To me, walking speed is not really about the legs. It is a window into the health of the brain.

This is one reason why experienced clinicians often pay close attention to how a patient walks into the room. Long before a cognitive assessment begins, there may already be clues present in the way someone moves.

Historically, these observations have been subjective. One practitioner notices something. Another does not. But that is beginning to change.

Today’s wearable technologies can continuously measure cadence, walking speed, stride length, variability, balance, and movement patterns. For the first time, we have the ability to monitor changes in movement over years rather than relying on a snapshot from a single office visit.

That is exciting because it aligns perfectly with where the field needs to go.

At TruNeura, we spend a lot of time thinking about how to identify cognitive decline earlier. The reality is that memory loss is often a late-stage symptom. By the time someone notices that they are forgetting things, the process may have been underway for years.

What makes these studies so interesting is that they suggest the brain is giving us signals much earlier. Not through memory, but through movement.

I am excited about a future where wearable devices can track walking speed, cadence, balance, and other markers continuously over time. Not because walking speed itself is the problem, but because it may be another window into how well the brain’s networks are functioning.

The more we learn about cognitive decline, the more it becomes clear that there is no single test that will tell us everything. Instead, we need to start paying attention to patterns. Changes in biomarkers. Changes in sleep. Changes in social engagement. Changes in movement.

Walking speed may be one more piece of that puzzle.

The lesson here is not that everyone should start obsessing over how fast they walk.

The lesson is that cognitive decline leaves clues.

There are many ways to spot the early signs of Alzheimer’s disease and other forms of dementia. Some people notice changes in memory. Others notice changes in mood, attention, executive function, or social engagement. Increasingly, research suggests that changes in movement may be part of that picture too.

Looking back, my own father’s walking speed and shuffling gait became much more obvious in the summer before he was diagnosed. At the time, it was easy to explain away as aging. Only later did it become clear that it was part of a much bigger story.

For decades, we have waited for memory symptoms to tell us that something is wrong. Increasingly, the science suggests that the brain has been telling us for years. We just have not been listening.

The opportunity now is to build systems that can recognize those signals earlier and intervene while there is still plenty of brain function left to protect.

Because when it comes to cognitive decline, the goal is not to diagnose it earlier.

The new goal is to prevent it from becoming a diagnosis in the first place.