Gait performance—the ability to walk steadily at a useful pace—is a strong predictor of falls. Because gait involves the incorporation of multiple cognitive and physical skills used to maintain balance, it is likely to be significantly affected by dementia and other cognitive decline. There is a lack of research, however, that compares gait and falls risk across the continuum of cognitive performance, which is needed to understand how cognition and gait affect falls risk in conditions such as mild cognitive impairment (MCI) and Alzheimer’s disease (AD).
A recently published study examines gait and cognition using “dual-task tests,” which simulate the kind of walking done in real-life situations. Researchers hypothesized that participants would experience a “dual-task cost” in their gait performance.[1] Dual-task gait assessment is closer to the kind of cognitive demands on real-life walking than is single-task gait assessment, in which the research participant is only asked to walk a set distance. This is because real-life walking usually involves multiple tasks; when we walk during our daily lives, we are usually involved in other activities such as social interaction, navigation, or other basic but cognitively-taxing processes.
Researchers also hypothesized that three groups of participants—cognitively healthy older adults; individuals with MCI; and individuals with AD—would differ in the amount of dual-task cost that they would experience. These groups differed in age and level of physical activity, as well as in cognitive ability. Participants were asked to walk at their normal speed along a six-meter electronic walkway. They were measured during single-task walking, as well as three dual-task walking conditions of varied difficulty: walking while naming animals and counting backwards from 100 by ones and sevens.
There was no significant difference among the groups in single-task walking, but the MCI and AD groups differed from the control groups in how they were affected by dual-task cost. These groups walked at a slower pace, with more time between steps and slower velocity during steps. The control group showed no difference across the varied dual-task assessments, but both the MCI and AD groups showed decreased gait performance with each increase in task difficulty. For example, they on average walked slower when counting back by sevens than when counting back by ones. In contrast to previous research, there was no statistically significant difference in performance between the AD and MCI groups.
This study provides useful evidence for falls risk screening and the development of falls assessment guidelines.
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[1] A dual-task is when a research participant is asked to perform two cognitively-taxing skills at once.
