Effects of divided attention on kinematic adaptations during obstacle-crossing in mild cognitive impairment

Older adults with mild cognitive impairment (MCI) exhibit memory deficits and impaired postural control, increasing their fall risk, especially during obstacle negotiation. The study aimed to examine the end-point control and kinematic changes of the pelvis-leg apparatus in older adults with MCI during dual-task obstacle crossing, and to compare these changes across different tasks and obstacle heights.

Eighteen older adults with single-domain amnestic MCI walked and crossed at three obstacle heights under single-task and cognitive-motor dual-task conditions. Pelvis orientations and lower-limb joint angles and associated end-point parameters, such as leading and trailing toe-obstacle clearances and crossing speeds were measured. Two-way analyses of variance were used to study within-subjects (task and obstacle height) effects on the variables.

Dual-task obstacle crossing led to significantly decreased crossing speeds and increased both leading and trailing toe-obstacle clearances (p < 0.05). Compared to single task, greater pelvic anterior tilt, upward list, hip flexion and abduction, and knee flexion in the swing limb, along with greater stance hip flexion were found during leading-limb crossing (p < 0.05). During trailing-limb crossing, greater pelvic posterior tilt and swing ankle dorsiflexion, but decreased pelvic upward list were found during dual task (p < 0.05).

Dual-task obstacle crossing induces significant kinematic adaptations in older adults with MCI, reflecting altered postural adjustments and end-point control. Monitoring these kinematic adaptations under dual-task obstacle crossing could serve as a valuable tool for assessing functional performance in MCI.