Examination of dynamic gait stability during overground walking in people with mild cognitive impairment.

Although mild cognitive impairment (MCI) is known to compromise balance in older adults, its influence on dynamic gait stability is less understood. This study is the first to examine dynamic gait stability within the Feasible Stability Region framework during level overground walking at a self-selected speed in individuals with MCI. Eighteen people with MCI (66.4 ± 5.9 years) and 20 age- and sex-matched healthy controls (66.9 ± 6.2 years) completed overground walking trials at their comfortable speed while their full-body kinematics were collected. Dynamic gait stability at touchdown and liftoff served as the primary outcome. Secondary outcomes included the center of mass velocity and position, along with standard spatiotemporal gait parameters. Dynamic gait stability was similar between groups at touchdown (p = 0.299) and liftoff (p = 0.185). However, people with MCI positioned their center of mass more anteriorly relative to the base of support than the healthy controls at touchdown (p < 0.001) and liftoff (p = 0.012). The center of mass velocity was slower in the MCI group than in cognitively healthy individuals at touchdown (p = 0.013) and comparable between groups at liftoff (p = 0.109). People with MCI exhibited a reduced gait speed (p = 0.018), decreased cadence (p = 0.018), shortened step length (p = 0.047), and prolonged stance phase (p = 0.067) compared to their healthy counterparts. Our study suggests that older adults with MCI adopt a cautious gait pattern, allowing them to maintain dynamic gait stability. These findings provide insight into the dynamic stability control in people with MCI during gait, broadening our understanding of dynamic balance control in human locomotion across populations.