Emerging research in small groups of elderly subjects has also found that a slower gait from year to year may be an early sign of cognitive decline. But not all signs of cognitive decline predict later dementia — only 10% to 20% of people age 65 or older with mild cognitive impairment or MCI develop dementia over the next year, according to the National Institute on Aging. Every other year, people in the study were asked to take cognitive tests that measured overall cognitive decline, memory, processing speed and verbal fluency. “Furthermore, dual decliners had a higher risk of dementia than those with either gait or cognitive decline alone,” Verghese wrote in an accompanying editorial published Tuesday in the JAMA journal. A dual association between walking speed and memory decline is predictive of later dementia, a 2020 meta-analysis of nearly 9,000 American adults found.