Five studies presented at the Alzheimer’s Association International Conference in Vancouver provide striking evidence that when a person’s walk gets slower or becomes more variable or less controlled, his cognitive function is also suffering.

Thinking skills like memory, planning activities or processing information decline almost in parallel with the ability to walk fluidly, these studies show.

In other words, the more trouble people have walking, the more trouble they have thinking.

“Changes in walking may predate actually observable cognitive changes in people who are on their way to developing dementia,” said Molly Wagster, chief of the National Institute on Aging’s behavioral and systems neuroscience branch. Experts said the studies could lead to developing a relatively simple tool that doctors could use to forecast, if not diagnose, possible Alzheimer’s disease.

“You can probably just watch them walk down the hall in your office and look for people who are starting to show deterioration in their gait and have no other explanation for it,” said William Thies, the chief medical and scientific officer for the Alzheimer’s Association. “If gait begins to deteriorate, we begin to have a conversation about how is your memory.”