Passively monitoring how quickly an individual walks in the home may provide clues about the development of mild cognitive impairment, suggest researchers from Oregon Health & Science University (Oregon, USA). Hiroko Dodge and colleagues studied undividuals 70 and older (mean age 84) who were living independently and who participated in the Intelligent Systems for Assessing Aging Change (ISAAC) cohort study. The homes of all of the participants were fitted with passive infrared sensors to measure walking speed. At baseline, there were 54 participants with intact cognition, 31 with nonamnestic mild cognitive impairment, and eight with amnestic mild cognitive impairment. The researchers focused on the individuals with nonamnestic impairment because the sample size was large enough for comparisons. Follow-up lasted 2.6 years. The researchers defined three groups based on mean walking speed — slow, moderate, and fast. The moderate and fast groups had slight declines in walking speed during the study, whereas the slow group had a more noticeable reduction. The individuals with nonamnestic mild cognitive impairment were about 9 times more likely to be in the slow group than in the fast and about 5 times more likely to be in the slow group than in the moderate group. The participants with nonamnestic mild cognitive impairment made up 16.7% of the fast group, 34.6% of the moderate group, and 66.7% of the slow group. Submitting that: “Walking speed and its daily variability may be an early marker of the development of [mild cognitive impairment],” the study authors conclude that: “These and other real-time measures of function may offer novel ways of detecting transition phases leading to dementia.”
