Dual-task standing in older adults with mild cognitive impairment: postural control complexity, prefrontal...

This study aimed to quantify prefrontal cortex (PFC) activation and postural control complexity in older adults with mild cognitive impairment (MCI) during single-task standing and dual-task standing balance conditions and to investigate the associations between these measures.

This secondary analysis included 21 older adults with MCI (71.19 ± 3.36 years) and 19 cognitively intact controls (70.16 ± 4.54 years) from a previously reported cohort. Outcomes included cognitive performance, sample entropy of COP displacement (SampEn-COP), PFC activation across four bilateral functional regions, and exploratory correlations between PFC activation and SampEn-COP.

A significant group effect was observed for SampEn-COPml, with lower values in the MCI group than in the control group (p = 0.002, η² _p = 0.217, q = 0.007). SampEn-COPap was significantly higher under the dual-task condition than under the single-task condition (p = 0.005, η² _p = 0.187, q = 0.016). Group × Task interactions were observed at the uncorrected level in the dorsolateral prefrontal cortex (DLPFC; p = 0.041, η² _p = 0.106, q = 0.073) and orbitofrontal cortex (OFC; p = 0.039, η² _p = 0.107, q = 0.073). The MCI group also showed lower cognitive accuracy and response rates than the control group across task conditions (both q < 0.01). An exploratory negative correlation between OFC activation and SampEn-COPap was observed in the MCI group under the single-task condition (r = -0.469, p = 0.032, q = 0.256).

Older adults with MCI showed a less complex medial-lateral postural control pattern than cognitively intact older adults. During dual-task standing, changes in postural complexity were accompanied by preliminary evidence of task-related increases in DLPFC and OFC activation in the MCI group, suggesting greater prefrontal involvement in managing concurrent cognitive and postural demands.