Predicting poststroke dyskinesia with resting-state functional connectivity in the motor network

Abstract

Significance: Motor function evaluation is essential for poststroke dyskinesia rehabilitation. Neuroimaging techniques combined with machine learning help decode a patient's functional status. However, more research is needed to investigate how individual brain function information predicts the dyskinesia degree of stroke patients.

Aim: We investigated stroke patients' motor network reorganization and proposed a machine learning-based method to predict the patients' motor dysfunction.

Approach: Near-infrared spectroscopy (NIRS) was used to measure hemodynamic signals of the motor cortex in the resting state (RS) from 11 healthy subjects and 31 stroke patients, 15 with mild dyskinesia (Mild), and 16 with moderate-to-severe dyskinesia (MtS). The graph theory was used to analyze the motor network characteristics.

Results: The small-world properties of the motor network were significantly different between groups: (1) clustering coefficient, local efficiency, and transitivity: MtS > Mild > Healthy and (2) global efficiency: MtS < Mild < Healthy. These four properties linearly correlated with patients' Fugl-Meyer Assessment scores. Using the small-world properties as features, we constructed support vector machine (SVM) models that classified the three groups of subjects with an accuracy of 85.7%.

Conclusions: Our results show that NIRS, RS functional connectivity, and SVM together constitute an effective method for assessing the poststroke dyskinesia degree at the individual level.

Keywords: dyskinesia; machine learning; motor network; near-infrared spectroscopy; stroke.

Fig. 1

NIRS-measured brain area schematic diagram.

Fig. 2

Time course of $\mathrm{\Delta }[{\mathrm{HbO}}_2]$ and $\mathrm{\Delta }[\mathrm{Hb}]$ at a typical channel (Ch13) from one Healthy subject (a), one Mild patient (b), and one MtS patient (c).

Fig. 3

Mean $C$ (a), $L$ (b), LE (c), GE (d), $T$ (e), $\gamma$ (f), $\lambda$ (g), and $\delta$ (h) for the three groups under each threshold. The shaded part indicates the standard error (SEM). The black, blue, and red small triangles represent significant differences between Healthy and Mild groups, Mild and MtS groups, and Healthy and MtS groups. (p < 0.05, FDR correction) under this threshold, respectively.

Fig. 4

AUC indicators of the small-world properties for the three groups, * indicates p < 0.05, ** indicates p < 0.01, and *** indicates p < 0.001 (LSD correction).

Fig. 5

Scatterplots of significant correlations between FMA and $C$-AUC (a), $LE$-AUC (b), $T$-AUC (c), and GE-AUC (d).

Fig. 6

(a) The confusion matrix of the classification result and (b) the ROC curves of the three SVM models.