Alterations of brain functional complex network in temporal lobe epilepsy patients: a functional magnetic resonance imaging study / 中华神经科杂志

ABSTRACT

Objective:To investigate longitudinal alterations of brain functional complex network by rest-stage functional magnetic resonance imaging (rs-fMRI) and graph theory in patients with temporal lobe epilepsy (TLE).Methods:A total of 13 TLE patients (TLE baseline group) and 13 healthy controls (healthy control group) were enrolled to observe alterations in complex functional network. The subjects were recruited in the Epilepsy Clinic of the First Affiliated Hospital of Guangxi Medical University from January 2015 to April 2018. For longitudinal analysis, TLE patients were followed-up for three years (TLE follow-up group). All participants underwent rs-fMRI and attention network test (ANT). Finally, a cross-sectional study was conducted by comparing the area under the curve (AUC) between the TLE baseline group and the healthy control group, and a longitudinal analysis was conducted by comparing the AUC between the TLE baseline group and the TLE follow-up group.Results:Cross-sectional analysis showed that the alerting function of the TLE baseline group was declined [The tonic alertness reaction time, phasic alertness reaction time and alertness were (727.00±126.07) ms, (692.85±132.37) ms, and (34.15±23.50) ms, respectively in the TLE baseline group, which were (639.87±81.41) ms, (589.50±80.59) ms, and (50.37±14.71) ms, respectively in the healthy control group, with statistically significant differences between the two groups ( t=-2.09, P=0.047; t=-2.41, P=0.024; t=2.11, P=0.045)]; the TLE baseline group demonstrated decreased clustering coefficient in left supplementary motor area (SMA.L)(AUC was 0.162±0.044, 0.189±0.021, respectively; t=-4.14, P=4.67E-04) and left inferior parietal supramarginal angular gyri (AUC was 0.178±0.021, 0.202±0.026, respectively; t=-2.42, P=0.024), and decreased nodal local efficiency in SMA.L (AUC was 0.239±0.045, 0.260±0.022, respectively; t=-4.13, P=4.77E-04) and left inferior temporal gyrus (AUC was 0.233±0.036, 0.253±0.027, respectively; t=-3.03, P=0.006) compared with the healthy control group, and both SMA.L clustering coefficient and nodal local efficiency were positively correlated with TLE patients′ duration ( r=0.652, P<0.05; r=0.611, P<0.05). Longitudinal analysis showed that the global network efficiency of the TLE follow-up group decreased (The AUC of the TLE baseline group was 0.182±0.008, and the AUC of the TLE follow-up group was 0.169±0.015, t=2.73, P=0.017), which was negatively correlated with alertness ( r=-0.617, P<0.05). Conclusions:TLE patients show impairment of topological properties of brain functional network. SMA.L is a significant node in network. Alterations of brain functional network associate with duration. The decline in global network efficiency may be a characteristic of progressive deficit to TLE.