The way older people walk may provide a reliable clue about how well their brain is aging and could eventually allow doctors to determine whether they are at risk of Alzheimer’s, researchers have found.

The study, involving thousands of older people in several countries, suggests that those whose walking pace begins to slow and who also have cognitive complaints are more than twice as likely to develop dementia within 12 years.

The findings are among the latest attempts to find and develop affordable, inexpensive diagnostic tools to determine whether a person is at risk for dementia. Last month, researchers attending the Alzheimer’s Association International Conference in Copenhagen presented several studies focused on locating biomarkers of dementia in its earliest stages.

Among other things, scientists reported a connection between dementia and sense of smell that suggested a common scratch-and-sniff test could be used to help identify onset of dementia, while other researchers suggested that eye scans could also be useful someday be able to detect Alzheimer’s. Different studies found a new abnormal protein linked to Alzheimer’s and a possible link between sleep disorders and the onset of dementia.

Now, researchers at the Albert Einstein College of Medicine of Yeshiva University and Montefiore Medical Center say that a simple test to measure a patient’s cognitive abilities and walking speed could provide a new diagnostic tool to identify people at risk for dementia. It could be especially important tool in low- and middle-income countries with less access to sophisticated and costly technology, the scientists said.

They cautioned, however, that slower walking speed is not by itself sufficient to determine whether a person has pre-dementia, as people’s gait can be affected by common age-related ailments such as arthritis or inner ear problems that affect one’s balance.

Alzheimer’s disease is the most common cause of dementia. More than 5 million Americans have been diagnosed with Alzheimer’s, and the numbers are expected to double by 2050 as the population ages.

The Einstein study, published last month by a team led by neurology and geriatrics professor Joe Verghese , sifted data on nearly 27,000 people from 17 countries. The subjects were at least 60 years old and free of dementia.

With a growing body of evidence that slowing gait occurs early in dementia, the researchers set out to determine whether older people with slower gaits would also be more likely to get dementia and suffer cognitive decline than those who did not.

Using a simple test that measured walking speed and cognitive abilities, the researchers focused on four of 22 studies that tested 4,812 people and then followed them with annual evaluations for 12 years to see how many developed dementia.

The researchers found that nearly 10 percent of the people suffered from motoric cognitive risk syndrome (MCR), a recently identified condition characterized by slowing walking speeds and cognitive lapses. They also found that the condition was a factor for cognitive decline. Walking speeds were measured in most cases by timing subjects over a short distance.

“Even though we think of walking as a automatic process, it really isn’t,” Verghese said in an interview Friday. “When you’re walking out in the real world, it’s a complex action.”

He said that as a young researcher into aging, he had noticed years ago that patients who were walking more slowly also performed poorly on cognigitive ability tests. In 2002, Verghese and others published a study in the 2002 New England Journal of Medicine showing that abnormal gait could be an indicator of dementia risk.

The latest study, which linked gait and cognitive complaints to dementia risk, appeared July 16 in Neurology, a journal of the American Academy of Neurology.