Effective Connectivity in Subjects With Mild Cognitive Impairment as Assessed Using Functional Near-Infrared Spectroscopy

Abstract

Objective This study aimed to reveal the physiological mechanism in subjects with mild cognitive impairment based on effective connectivity method. Methods Effective connectivity was assessed by dynamic Bayesian inference of the oxygenated hemoglobin concentration signals measured through functional near-infrared spectroscopy. The oxygenated hemoglobin concentration signals were recorded from the left prefrontal cortex, right prefrontal cortex, left motor cortex, right motor cortex, left occipital lobe, and right occipital lobe of 26 subjects with mild cognitive impairment (mild cognitive impairment group) and 28 healthy elderly subjects (control group) at resting state. Results The coupling strength of right prefrontal cortex to left prefrontal cortex (F = 7.964, P = 0.007) and left prefrontal cortex to right occipital lobe (F = 4.278, P = 0.044) in interval III as well as left prefrontal cortex to left occipital lobe (F = 5.637, P = 0.021), right occipital lobe to left prefrontal cortex (F = 4.762, P = 0.034), and right prefrontal cortex to left occipital lobe (F = 4.06, P = 0.049) in interval IV in the mild cognitive impairment group were significantly lower than those in the control group. Conclusions The decreased effective connectivity levels among brain regions may be a marker of impaired cognitive function in the mild cognitive impairment group. The constructed effective connectivity network based on functional near-infrared spectroscopy provide a noninvasive method to assess mild cognitive impairment.

Quantitative Assessment of Resting-State for Mild Cognitive Impairment Detection: A Functional Near-Infrared Spectroscopy and Deep Learning Approach

“…Through studies over the past decade, researchers have demonstrated the feasibility of using fNIRS to identify reduced cerebral oxygenation either in the resting state or the task period, such as during word retrieval, memory tasks, motor tasks, and visuospatial perception [28]. In the resting-state cases, altered connectivity [29][30][31] and fluctuations [32][33][34][35][36] of cerebral oxygenation have been reported in MCI and AD groups. This difference is associated with the dysregulation of information integration in the patient's brain.…”

A Systematic Review of Cerebral Functional Near-Infrared Spectroscopy in Chronic Neurological Diseases—Actual Applications and Future Perspectives

“…We have therefore focused our attention on the current state-of-the-art of fNIRS applications dealing with motor and cognitive disability in the most frequent chronic neurological disorders of the elderly, namely PD and the AD continuum and MS as the most frequent chronic neurological disease of young and middle-aged adults. Our results reveal that AD and MCI are the most frequently addressed conditions by a wide variety of fNIRS applications, ranging from the monitoring of tissue oxygenation and vasomotor reactivity [ 65 , 66 , 67 , 68 , 69 , 70 ], to the analysis of resting-state conditions [ 64 , 71 , 72 , 73 ], the assessment of cognitive functions by means of memory and verbal fluency tasks [ 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 91 , 92 , 93 ], visuospatial functions [ 94 , 95 ] and other ecological applications [ 96 , 97 ]. Within the broad context of PD and MS, reviewed studies were more focused on the assessment of motor functions [ 51 , 53 , 54 , 55 , 56 , 109 , 110 , 112 ].…”

“…Low frequency oscillations were also correlated with performance on neurophysiological tests. Accordingly, Bu et al [64] assessed resting-state effective connectivity across the PFC, motor and occipital cortices by means of dynamic Bayesian interference. MCI patients showed a decreased connectivity compared to HCs most notably in the PFC, as well as positive correlations with cognitive performance assessed by means of the MMSE and the Montreal Cognitive Assessment.…”

“…In most of the reviewed applications, fNIRS probes were placed over the PFC, as this cortical area is mainly associated with high-level processing functions [ 64 ]. We identified 40 studies performed with a total of 977 AD and 477 MCI patients (208 amnestic MCI), as well as with 792 age-matched HC subjects ( Table 2 ) Most studies were addressed to the monitoring of tissue oxygenation [ 65 , 66 , 67 , 68 , 69 , 70 ], the investigation of functional resting-state activity and connectivity [ 64 , 71 , 72 , 73 ], the assessment of specific cognitive functions [ 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 91 , 92 , 93 ] such as visuospatial deficits [ 94 , 95 ] and additional ecological applications [ 96 , 97 ]. Though most studies reported cross-sectional reports, we also retrieved six longitudinal ones [ 98 , 99 , 100 , 101 , 102 , 103 ], thus strongly supporting the idea that fNIRS can represent a viable tool for long-term monitoring of cerebral activity from the early phases of the disease or during rehabilitation.…”

The Effects of Two Game Interaction Modes on Cortical Activation in Subjects of Different Ages: A Functional Near-Infrared Spectroscopy Study

“…We used a multi-channel near-infrared system (Nirsmart, Danyang Huichuang Medical Equipment Co., Ltd., China) in this experiment [23]. The sampling frequency was set to 10 Hz.…”