高齢者におけるバランス自動性とデュアルタスク干渉の関係

Age-related decline can impair older adults' ability to perform tasks involving a mix of motor and cognitive goals in a dual-task (DT) paradigm. The amount of DT interference effects has typically been associated with the availability of attentional resources and the degree of balance automaticity. Older adults with mild cognitive impairment may lack sufficient sensorimotor capacity for "automatic" regulation of posture under demanding balance conditions, resulting in larger DT interference effects due to increasing attentional control.

Does the degree of automaticity affect balance stability in older adults with mild cognitive impairment during dual tasking, and does this relationship vary with the difficulty of the balance task?

Sixty-seven older adults, aged 60-80 years (23 mild cognitive impairmentss), were positioned barefoot on a single piezoelectric force plate in a double-support and tandem stance with eyes open. Each stance condition was tested as single task during performance of a mathematical counting task (i.e., DT). DT cost (DTC) scores of center-of-pressure sway velocity (DTCVcop) were calculated, and regression analyses were conducted to assess the unique contribution of baseline center-of-pressure sway entropy under single-task conditions to DTCVcop, with age, Montreal Cognitive Assessment scores, gender, and cognitive status included as covariates.

Baseline sway entropy accounted for only 0.25%-4% of the variance in DTC of Vcop. Gender and cognitive status accounted for 12%-20% of the variance under double-support but not in tandem stance.

Our findings suggest that sway entropy has only minimal impact on DT interference while gender and cognitive status play a more substantial role, highlighting the importance of these factors in balance control of older adults.