"One of the attractions for me is that observing gait is not particularly high-tech and can be done in simple ways," Thies said. "We have lots of primary care physicians sometimes having difficulty picking out patients that need further evaluation. This is a potential tool not for diagnosis, but for knowing who needs more evaluation."
One study of more 1,100 people with an average age of 77 found that people with Alzheimer's disease walked more slowly and with a more irregular pattern of steps as their minds declined. Even people with a pre-Alzheimer's condition, called mild cognitive impairment, walked more sluggishly and variably than the normal elderly, according to the study led by Stephanie Bridenbaugh, from the Basel Mobility Center in Switzerland.
Bridenbaugh's group used a computerized pad that patients walk on to detect minute variations in their gaits. While a general practitioner probably wouldn't have that available in the office, asking patients to count backward by two while they walked and observing any changes in their stride could be helpful, she said. Though everyone walks more slowly while counting backward, troubles with balance or an unusual stride become more obvious when double-tasking.
Additionally, the double-task analysis may help doctors figure out which adults are walking more slowly because of pain, rather than brain changes, she said.
Another study of more than 1,200 people over age 49, found that the rhythm of a person's stride was associated with information processing speed. The ability to control and regulate behavior, called executive function, was associated with stride length. Memory wasn't correlated with any aspect of walking, according to the study led by Mohammad Ikram, a researcher at Erasmus Medical Center in Rotterdam, the Netherlands.
"Future studies should explore the link between gait and dementia," Ikram said. "Can we use gait to predict dementia? If so, how long before cognitive symptoms?"
A third study evaluated patients over multiple visits. It found that those who had slower steps and smaller strides had larger declines in thinking, memory and executive processing, according to the study led by Rodolfo Savica from the Mayo Clinic in Rochester, Minnesota.
"Motor and cognitive function may be part of the same spectrum of the disease," Savica said. "These motor changes happen before the memory changes."
Most older adults walk more slowly as they age, the doctors said. Any analysis of a person's stride should take into account the full medical work-up, Savica said. It's important to know whether patients are walking more slowly because they have an arthritic knee or a bone disease, he said.