Study Of The Damage Of Cognitive Function And Functional Brain Network In Temporal Epilepsy

Objective To figure out the relationship between the cognitive impairment in patients with temporal lobe epilepsy(TLE),and the change characteristics about patients’ brain function network by using the resting-state functional magnetic resonance imaging(RS-f MRI)technology.Meanwhile,analyze the influence of seizure frequency to the cognitive function and brain function network for controlling seizure and avoiding cognitive function damage in clinical.Method Nineteen patients(male N=8)who were fulfilled the TLE diagnosis(ILAE,2001),from July 2016 and Dec 2016 in The Department of epilepsy in Tianjin medical university General Hospital,were enrolled as case group.The were underwent the long term VEEG monitoring Fifteen healthy volunteers(male N=8)in concordance with gender,age,education with patients group.The average age were 33.4±10.8 and 32.1±9.6 years old in case group and healthy control,respectively.We collected the clinical material and subdivided case group into high frequent group(times≥4,N=9)and low frequent group(times <4,N=10)according to the frequency of seizure per mouth.The average frequency of seizure were 11.3±6.2 and 1.0±0.7 in two group,respectively.All members in our cohort were right-hander and cooperated.Neuropsychological assessment including Mo CA,attention(including digit span subtest,DST and synbol digit modalities Test,SDMT),cognitive flexibility(block diagram,BD and trail making test,TMT including TMT A、TMT B、distraction),memory(auditory verbal memory test,AVMT and complax tigure Test,CFT)and MRI and RS-MRI were tested in case group and healthy control.Then the results were comparatively analysed.Results(1)The case group had a higher MOCA score and lower attention,cognitive flexibility,and memory than healthy control group,and the difference was statistically significant(p<0.05)except imitation in CFT and long delayed memory in AVMT.Compared with the healthy control,the increased abnormal activation of brain areas in case group were parahippocampal gyrus,inferior temporal gyrus,prefrontal lobe,orbital straight gyrus,the anterior cingulate gyrus and striatum(p<0.05),while the decreased areas were superior and middle frontal gyrus,the anterior cingulate gyrus,orbital gyrus,caudate nucleus,medial occipitotemporal gyrus,the corpus callosum and occipital lobe,respectively(p<0.05)(2)When compared with high frequency group and low frequency group,there was no significant difference among their gender,age,education,sides and seizure type.In both high and low frequency group,except TMT were longer time,other tests’ score were lower when compared with healthy control.To high frequency group,the difference about MOCA,attention,TMT B,time of distraction,long and short delayed memory of CFT and AVMT except 1 test was statistically significant(p<0.05),when compared to control.While low frequency group,there were significant differences(p<0.05)among MOCA,attention,TMT B,long and short delayed memory in CFT,short delayed memory,3 test’ serial number and long delayed memory’ serial number in AVMT.Furthermore,compared to low frequency group,high frequency group had lower score of short delayed memory in CFT and 3rd test in AVLT,and the difference was statistically significant(p<0.05).Compared with the high and low frequency groups showed increased abnormal activation of brain areas in left postcentral gyrus,right precentral gyrus,right parahippocampal gyrus,right precuneus(P<0.05).While the decreased areas in the bilateral cerebellum,left insula,left middle temporal gyrus left inferior frontal gyrus,left precentral gyrus,right superior temporal gyrus,right anterior cingulate(P<0.05).Conclusion ⒈ Patients with TLE has damage of general cognitive function,attention,memory,cognitive flexibility despite of high or low frequency.However higher frequency may correlate with worsen memory function.⒉In rest condition,the abnormal activated brain areas referre to more extensive area not only temporal lobe,but also occipital lobe and frontal lobe which reminded that abnormal discharge of TLE patients may lead to abnormal activity of local neuron,then affect the normal brain network connection through a certain network and traveling around,to damage the message transmission and cognitive function.⒊Frontal lobe,temporal lobe and precuneus are the main abnormal activated brain areas and the main abnormal decreased areas is cerebellum in patients with high frequency TLE,which prompted that there is inhibition with cerebellum for seizure.The different frequency affectes brain network in different degree which may lead to different degree of cognitive function damage.There is more severe memory damage in patient with more frequent seizure in temporal lobe,which is the center of main function memory area.It is important to control epilepsy,decrease and even eradicate seizure in clinical.⒋RS-f MRI is a useful test which can detect the early change of brain network in patients with TLE and the further cognitive function damage.It can guide doctors decide an early and effective therapy for seizure controlling,to decrease and avoid the damage of cognitive function.