Resting-state Brain Entropy Alterations In Right Temproal Lobe Epilepsy And The Relationship With Alertness

Objectives: As an important brain function,including memory,executive,attention and other cognitive functions in patients with temporal lobe epilepsy in varying degrees of damage,and there are few studies on vigilance function.The brain entropy is an indicator of brain complexity and is rarely used in epilepsy study.In this study,resting-state functional magnetic resonance imaging(fMRI)was used to study the changes of brain entropy and its relationship with alertness function in patients with right temporal lobe epilepsy.Methods: We used the attention network test to evaluate the alertness in 31 rTLE patients and 33 healthy control subjects;at the same time took the resting state functional magnetic resonance(rs-fMRI)and 3D(3D-T1)structure scan.Calculated the brain entropy map of the two groups of subjects,and then defined the brain regions which shown significant difference in the two sample t test(p<0.01)as the regions of interest(ROI),extracted the entropy of them,and work out the relationship between brain entropy and alert function.Then calculated the function connectivity map between the regions of interest and the whole brain,and a two sample T test was used of the maps between the twogroups.At the end,extracted the average FC value of the ROIs,and correlated with alertness and BEN of ROIs respectively.Results:1.The intrinsic alertness reaction time of rTLE patients(685.44 +111.45ms)and phasic alerness reaction time(648.23 + 115.84ms)were significantly increased(p=0.000)than the healthy controls(intrinsic alertness RT:596.02 + 54.97 ms,phasic alertness RT: 552 + 54.67ms),while the alertness RT of rTLE patients(37.21 + 27.84ms)and normal people(44.02 + 19.01ms)did not find a statistically significant difference(p=0.254);2.Compared with normal controls,the brain entropy of rTLE patients significantly increased in the right temporal gyrus,inferior temporal gyrus,left superior and middle frontal gyrus,and left middle occipital gyrus,left insula,putamen,left posterior cerebellum,while decreased significantly in the right middle frontal gyrus,left supplementary motor area(p<0.05,Alphasim correction,single voxel p<0.01,voxel >140);and when the p<0.01,BEN of patients with rTLE was decreased in the left superior parietal lobule,right precentral gyrus(this two brain regions were defined as ROI1 and ROI2);3.The BEN of ROI2 was associated with the intrinsic alert RT of patients with rTLE(Spearman rank correlation,rs=0.441,p=0.013)and phasic alertness RT(Spearman rank correlation,rs=0.429,p=0.016).No correlation was found between ROI1 and alertness.4.Compared with normal subjects,the function connectivity in patients with rTLE were increased between ROI1 and right cerebellar tonsil,right anterior lobe of cerebellum,right thalamus,right insula,left superior temporal gyrus,right inferior frontal cortex,left middle frontal gyrus cortex,left middle occipital gyrus,right middle cingulate gyrus,right precuneus,and decreased in left precuneus,left middle temporal gyrus(p<0.01,Alphasim correction,voxel>18);the FC value between ROI2 and right superior temporal gyrus,left postcentral gyrus subcortical was increased,and decreased with right fusiform gyrus(p<0.01,Alphasim correction,voxel >18).5.There was no correlation between the average FC value of ROI1,ROI2 and BEN of ROI1、ROI2 and the alertness function in the patients with rTLE.Conlusion:Our findings suggest the brain entropy and function connectivity in patients with rTLE have altered,and lower right precentral gyrus entropy might involve compensatory effects on the alert functions,and the brain where entropy changed showed the reconstruction of brain functional connectivity.These findings may improve our understanding of the brain function of patients with rTLE,provide new ideas for future research of epilepsy.