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

Abstract

Background 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. Methods 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. Results A significant group effect was observed for SampEn-COPml, with lower values in the MCI group than in the control group (p = 0.002, η2p = 0.217, q = 0.007). SampEn-COPap was significantly higher under the dual-task condition than under the single-task condition (p = 0.005, η2p = 0.187, q = 0.016). Group × Task interactions were observed at the uncorrected level in the dorsolateral prefrontal cortex (DLPFC; p = 0.041, η2p = 0.106, q = 0.073) and orbitofrontal cortex (OFC; p = 0.039, η2p = 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). Conclusion 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.