Early screening model for mild cognitive impairment based on resting-state functional connectivity: a functional near-infrared spectroscopy study

Abstract

Significance: As an early stage of Alzheimer's disease (AD), the diagnosis of amnestic mild cognitive impairment (aMCI) has important clinical value for timely intervention of AD. Functional near-infrared spectroscopy (fNIRS)-based resting-state brain connectivity analysis, which could provide an economic and quick screening strategy for aMCI, remains to be extensively investigated.

Aim: This study aimed to verify the feasibility of fNIRS-based resting-state brain connectivity for evaluating brain function in patients with aMCI, and to determine an early screening model for auxiliary diagnosis.

Approach: The resting-state fNIRS was utilized for exploring the changes in functional connectivity of 64 patients with aMCI. The region of interest (ROI)-based and channel-based connections with significant inter-group differences have been extracted through the two-sample $t$ -tests and the receiver operating characteristic (ROC). These connections with specificity and sensitivity were then taken as features for classification.

Results: Compared with healthy controls, connections of the MCI group were significantly reduced between the bilateral prefrontal, parietal, occipital, and right temporal lobes. Specifically, the long-range connections from prefrontal to occipital lobe, and from prefrontal to parietal lobe, exhibited stronger identifiability (area under the ROC curve $>0.65$ , ** $p<0.01$ ). Subsequently, the optimal classification accuracy of ROI-based connections was 71.59%. Furthermore, the most responsive connections were located between the right dorsolateral prefrontal lobe and the left occipital lobe, concomitant with the highest classification accuracy of 73.86%.

Conclusion: Our findings indicate that fNIRS-based resting-state functional connectivity analysis could support MCI diagnosis. Notably, long-range connections involving the prefrontal and occipital lobes have the potential to be efficient biomarkers.

Keywords: amnesic mild cognitive impairment; functional connectivity; functional near-infrared spectroscopy; resting state.

Fig. 1

The arrangement of measuring channels. Each ball represented a channel (CH), and the color indicated which region the channel belongs to. The nine ROIs were as follow: LPF = left prefrontal lobe; RPF = right prefrontal lobe; LT = left temporal lobe; P = superior parietal lobe; RT = right temporal lobe; LIP = left inferior parietal lobe; RIP = right inferior parietal lobe; LO = left occipital lobe; and RO = right occipital lobe.

Fig. 2

The inter-group differences in whole-brain mean functional connectivity. Black and grey points represent the HC and MCI groups, respectively. Asterisk indicates an extremely significant difference ($**p<0.01$).

Fig. 3

Regional differences in functional connectivity. Red lines indicate significant inter-group differences in the regional connection.

Fig. 4

(a) The ROC curves of the top six long-range connections in ascending order: RPF-RO (orange), RPF-LIP (purple), LPF-LO (blue), RPF-P (green), LPF-P (black), and RPF-LO (red). (b) The inter-group differences in the top six ROI-based functional connections. The color settings of the connections are consistent with (a). Circles and triangles represent the HC and MCI groups, respectively. Asterisk indicates an extremely significant difference (**$p<0.01$).

Fig. 5

(a) Channel-based connections with inter-group differences ($*p<0.05$). (b) Connections with highly significant difference (**$**p<0.01$).