Problems walking and talking or thinking at the same time might be a warning sign of impending dementia, a new study suggests.
Being unable to juggle two tasks simultaneously has been recognized as a sign of mental (or "cognitive") decline after age 65, but this research shows that the ability actually starts to fall off in middle-age. The finding could spur calls for earlier screening, researchers say.
"The ability to maintain walking performance while performing another task, a common scenario of walking in daily life, starts to decline in the middle of the sixth decade of lifespan," said lead researcher Junhong Zhou. He is an assistant scientist at the Hinda and Arthur Marcus Institute for Aging Research at Harvard Medical School, in Boston.
The decline of dual-task walking can lead to falls and injuries. Zhou said it is closely linked to thinking skills and underlying brain function.
"This outcome would be a marker for brain health and, in turn, taking interventions that target cognitive function may help preserve and enhance the dual-task walking, reducing the risk of dementia in later life," Zhou said.
With advancing age, the brain's ability to handle multiple tasks at the same time is diminished, he noted.
And the ability to dual task while walking drops off by age 55 — up to a decade sooner than what is traditionally defined as "old age," the study found. Researchers described their investigation as the first to characterize links between age, dual-task walking and mental function in healthy middle-age adults.
"Older adults oftentimes concentrate more on one task, and the task prioritization mainly depends on the importance of tasks, for example, in dual-task walking, they may put more focus on the maintenance of walking so that they may not fall down," he said.
There are several contributors to the decline in dual-tasking skills, and most are related to brain health, Zhou said.
Studies showed that as old age begins, connections between neurons in the brain drop, taking a toll on their efficiency, especially in brain regions involved in attention, as well as processing information.
"These kinds of age-related alterations in neuronal activities are associated with diminished brain function, which is an important contributor to such age-related declines in dual-tasking capacity," Zhou said.
For the study, Zhou and his colleagues collected data on nearly 1,000 people in Spain who took part in the Barcelona Brain Health Initiative between May 2018 and July 2020. Of those, more than 600 were evaluated for their ability to walk and think at the same time.
Zhou said that "older people had poorer dual-task walking performance, which suggests that cognitive function and/or underlying brain health contributed significantly to the variance."
Studies have shown that those with a greater inability to do two things at once have a significantly greater risk of developing dementia, Zhou said.
"The performance of dual-tasking, in the fields of neurology and aging, is an important marker of brain health," he explained. "This age-related decline of dual-task walking may indicate, at a much earlier age, when interventions should start."
The findings were published online March 17 in The Lancet Healthy Longevity.
For more on dementia, head to the Alzheimer's Association.
SOURCES: Junhong Zhou, PhD, assistant scientist, Hinda and Arthur Marcus Institute for Aging Research, Harvard Medical School, Boston; The Lancet Healthy Longevity, March 17, 2023, online