Effects of a reactive task on gait initiation in elderly individuals with mild cognitive impairment

Background: Older adults with mild cognitive impairment (MCI) exhibit deficits in motor control alongside cognitive decline. Gait initiation, a complex motor task, involves dynamic postural adjustments, fall risk, and cognitive demands. Reaction time tasks increase attentional and cognitive requirements. This study examined whether gait initiation differs between individuals with MCI and cognitively healthy adults and whether a reaction time task influences performance. Methods: A total of 30 participants were recruited, including 11 individuals with MCI and 19 cognitively healthy controls. Gait initiation was assessed under two conditions: self-initiated and light-triggered reactive gait initiation. Biomechanical parameters were collected using high-speed motion capture cameras and force plates, measuring center of pressure (COP) and center of mass (COM) movement time, displacement, and velocity, as well as gait parameters such as step length, step width, and landing angle. A two-way mixed ANOVA was conducted to examine the effects of cognitive function and task condition on gait initiation performance. Results: Older adults with MCI exhibited shorter movement time, shorter COP displacement, and faster COP velocity when performing gait initiation under the reaction time task. Under the reactive time task condition, both groups demonstrated shorter total gait initiation time, greater COP displacement, faster COP velocity, shorter COM displacement, slower COM velocity, and shorter step length. Conclusions: Gait assessment in older adults with MCI should include gait initiation analysis, preferably incorporating reactive time tasks. Particular attention should be given to COP parameters in result interpretation.