Correlation Between Gait and Near-Infrared Brain Functional Connectivity Under Cognitive Tasks in Elderly Subjects With Mild Cognitive Impairment

Abstract

Older adults with mild cognitive impairment (MCI) have a high risk of developing Alzheimer’s disease. Gait performance is a potential clinical marker for the progression of MCI into dementia. However, the relationship between gait and brain functional connectivity (FC) in older adults with MCI remains unclear. Forty-five subjects [MCI group, n = 23; healthy control (HC) group, n = 22] were recruited. Each subject performed a walking task (Task 01), counting backward–walking task (Task 02), naming animals–walking task (Task 03), and calculating–walking task (Task 04). The gait parameters and cerebral oxygenation signals from the left prefrontal cortex (LPFC), right prefrontal cortex (RPFC), left motor cortex (LMC), right motor cortex (RMC), left occipital leaf cortex (LOL), and right occipital leaf cortex (ROL) were obtained simultaneously. Wavelet phase coherence was calculated in two frequency intervals: low frequency (interval I, 0.052–0.145 Hz) and very low frequency (interval II, 0.021–0.052 Hz). Results showed that the FC of RPFC–RMC is significantly lower in interval I in Task 03 compared with that in Task 02 in the MCI group (p = 0.001). Also, the right relative symmetry index (IDpsR) is significantly lower in Task 03 compared with that in Task 02 (p = 0.000). The IDpsR is positively correlated with the FC of RPFC–RMC in interval I in the MCI group (R = 0.205, p = 0.041). The gait symmetry such as left relative symmetry index (IDpsL) and IDpsR is significantly lower in the dual-task (DT) situation compared with the single task in the two groups (p < 0.05). The results suggested that the IDpsR might reflect abnormal change in FC of RPFC–RMC in interval I in the MCI population during Task 03. The gait symmetry is affected by DTs in both groups. The findings of this study may have a pivotal role in the early monitoring and intervention of brain dysfunction among older adults with MCI.

Alterations in brain functional connectivity in patients with mild cognitive impairment: A systematic review and meta‐analysis of functional near‐infrared spectroscopy studies

“…Additionally, the FC of the left prefrontal to the left motor cortexes was significantly higher in the MCI group than that in the HC group in naming animalswalking task (Liu et al, 2021). They further demonstrated that the significantly different FC between groups were negatively correlated with relative symmetry index (IDps), suggesting that gait parameters might reflect the abnormal changes in FC in MCI individuals (Liu et al, 2021). Wang et al (2022) revealed that the FC of MCI patients was generally weakened compared to that of the HC during calculatingwalking task, with the brain regions showing decreased FC mainly associated with the left prefrontal cortex and the right prefrontal cortex.…”

“…Eventually, 13 studies were included in this systematic review and meta‐analysis. Among them, 13 studies were included in the qualitative synthesis (Bu et al., 2019 ; Ghafoor et al., 2019 ; Li et al., 2019 ; Liu et al., 2021 ; Nguyen et al., 2019 ; Niu et al., 2019 ; Tang & Chan, 2018 ; Wang et al., 2022 ; Yang & Hong, 2021 ; Yoo & Hong, 2019a , 2019 b ; Yu et al., 2020 ; Zhang et al., 2022 ), whereas only 2 studies met the criteria for quantitative synthesis (Bu et al., 2019 ; Zhang et al., 2022 ). The PRISMA flow diagram of the literature search and study selection strategy is shown in Figure 1 .…”

Neural Mechanisms of Motor Dysfunction in Mild Cognitive Impairment and Alzheimer’s Disease: A Systematic Review

“…Of the selected studies, 9 reported brain by group interactions on motor performance (see Table 1 ) and 29 reported other types of associations between motor function and neural measures in MCI and AD (see Table 3 ). Because one study reported both types of associations [ 21 ] and is therefore discussed under both headings, the total number of studies in both categories adds up to 38 instead of 37.…”

“…Participants with AD with a high lesion load have shown a higher dual tasking cost for cadence (steps per unit time) than control participants with either a low or high WML lesion load during treadmill walking while concurrently completing an n-back working memory task [ 25 ]. fNIRS studies have linked dual tasking deficits in MCI to both reductions in brain activation [ 26 ] and stronger functional connectivity [ 21 ]. Compared to controls, MCI participants exhibited lower brain activation in the prefrontal cortex during a task that involved walking while reciting alternate letters of the alphabet.…”

“…They also found that individuals with MCI had a larger decline in prefrontal cortex activation during walking at normal pace [ 26 ]. Participants with MCI also showed less prefrontal brain activation but stronger connectivity of the left prefrontal cortex with the left motor cortex and the right occipital cortex when walking while performing a cognitive task [ 21, 26 ]. Gray matter of the inferior temporal lobule and inferior and middle temporal gyrus were strongly related to motor-cognitive dual tasking performance in MCI, while this association was weak to absent in control participants [ 30 ].…”