Association of Dual-Task Gait With Incident Dementia in Mild Cognitive Impairment

This research from Montero-Odasso and colleagues investigated how speed of walking while performing a demanding cognitive task can predict whether a patient with Mild Cognitive Impairment (MCI) might later develop dementia. MCI, a condition where individuals present with small changes in their memory and mental functions, is often a precursor to dementia, though not everyone who has MCI goes onto develop dementia. Montero-Odasso and colleagues followed 112 older adults over six years who presented with MCI. Every two years, the participants were asked to first walk normally for six meters without doing a simultaneous task (single-task), and then to walk while simultaneously doing a secondary task that requires thinking and attention, such as counting backwards by one, by seven, or while naming animals (dual-task). In all tasks, the participants’ walking speed was measured. Over six years, 24% of the initial sample of older adults with MCI (27/112) developed dementia. The researchers found that the mean normal (single-task) walking speed of these 27 older adults was equivalent to the normal walking speed of the 85 older adults who did not develop dementia. In contrast, the older adults who eventually developed dementia were slower than those that did not develop dementia when they were walking while simultaneously doing a secondary task (e.g. counting backwards, or naming animals). In fact, the risk of progressing to dementia was two to three times greater in older adults with MCI whose walking speed diminished by at least 20 percent (e.g. slowing from one meter per second to 0.8 meters per second) in the dual-task walking condition relative to the single-task walking condition. The results of this study suggest that a significant slowing down in walking speed while doing a cognitively demanding task relative to normal walking speed (without doing a cognitively demanding task) can be used by clinicians to detect older adults with MCI who are at risk of developing dementia.