Spontaneous Brain Activity Of Benign Epilepsy With Centrotemporal Spikes:Resting-state FMRI Study

Benign epilepsy with centrotemporal spikes (BECTS) is one of the most common epilepsy syndromes and belongs to a class of epilepsy syndromes called idiopathic partial epilepsies of childhood. BECTS has been traditionally thought to be a benign syndrome, resulting in few if any neurodevelopmental problems. However, more recent neuroimaging research, especially a non-invasive and high spatial resolutionfunctional magnetic resonance imaging (fMRI) has suggested thatBECTS can be associated with some neurocognitive problems and deficits of brain function.Recently, the resting-state fMRI which differs with conventional external task-related fMRI paradigm mainly focuses the intrinsic spontaneous brain activity during task-free state. It provides a simple and feasible way to map the pattern of spontaneous brain activityfor the patient with epilepsy, especially for epilepsies of childhood.In the present work, we employed the resting-state fMRI to investigate the changes of local properties of blood oxygenation level-dependent (BOLD) activation in BECTS. Frist, given the epileptic activity has presentations of highly synchronization of local neuronal activity, we used an regional homogeneity(ReHo) analysis to observe the changes of local synchronization of BOLD activationinduced by epileptic activity. In addition, given the interictal epileptic activity has electrophysiological presentations of high amplitude of neuronal activity, correspondingly, we used an amplitude of low-frequency fluctuation (ALFF) analysis to observe the changes of amplitude of BOLD activation induced by epileptic activity. Finally, we expected to detect the epileptic activation in individual BECTS using ALFF. In sum, the current work translate the resting-state fMRI to assess the clinical applications, and understand the pathophysiological mechanisms of BECTS. Three are three parts in the dissertation.Part I:Regional Homogeneity Abnormalities in Patients With Benign Epilepsy with Centrotemporal SpikesPurpose:Epileptic activity originates with abnormally increased local synchronization in electrophysiology. We hypothesized that the epileptic activity may evoked hemodynamic response alteration in functionally related brain regions, which may be identified by regional homogeneity (ReHo) on resting-state fMRI data.Methods:We acquired resting-state fMRI data of30patients with benign epilepsy with centrotemporal spikes (BECTS) and20controls (under3.0T scanner). ReHo was computed for each participants and compared between patients and controls.Results: As compared to controls, patients showed higher ReHo in bilateral precentral gyrus, right postcentral gyrus, right supramarginal gyrus, left superior frontal gyrus, left inferior frontal gyrus and superior parietal lobule; lower ReHo in bilateral temporal lobule, bilateral obit frontal cortex and putamen. We observed significant positive correlation between ReHo in left superior frontal gyrus and disease duration.Conclusion:Based on the regional feature of resting-state fMRI signal, we found enhanced ReHo in bilateral central area and prefrontal cortex; and decreased ReHo in limbic system in patients with BECTS. These findings provided new evidences to understand the pathophysiology of BECTS. Part Ⅱ. The Resting-State fMRI Study of Spontaneous BrainActivity for Benign Epilepsy With Centrotemporal SpikesPurpose:Based on abnormal epilepsy activity with high amplitude EEG discharges could result in BOLD signal changes, amplitude of low-frequency fluctuation(ALFF) was used for analyzing the amplitude of BOLD signal changes of epilepsy in this study. Method:There were30BECTS children in this study. The MR images were acquired using a3-Tesla scanner. ALFF, the resting state analysis method, was used in this study to detecte the abnormal brain areas between patients and20healthy controls.Results:The results suggested that ALFF value of BECTS patients was significant higher in bilateral precentral gyrus, right postcentral gyrus, right supramaginal gyrus, right frontal lobe, right pallidum and significant lower in left cerebellum, right inferior tempotal gyrus, right inferior frontal gyrus, left rectus gyrus, left superior parietal gyrus and left middle occipital gyrus.Conclusion:ALFF was used in this study to detect the abnormal spontaneous neural activity of BECTS patients. Our results suggested that the significant higher ALFF was mainly located in central area. ALFF of central area was correlated with IQ, performance IQ and duration. These discovery suggested that IED may result in spontaneous activity changes for BECTS patients and right precentral gyrus may be related to lower performance ability. Part Ⅲ. The Localization of Epileptic Foci forBenign Epilepsy With Centrotemporal Spikes Patients Using Resting-statePurpose:As we know that BOLD signals can be response to the abnormal discharges for epilepsy. So we planed to compare ALFF of every patient with the ALFF of all controls to localize the epileptic foci for those patients who had no discharges during the experiments.Methods:Thirty BECTS patients and20normal controls were concluded. Functional imaging data were acquired on a3.0Tesla MRI scanner. We compared ALFF of one patient with ALFF of all normal controls to localize the epileptic foci. To assess the results we also analyzed these data using GLM method.Results:Comparing the two results, we found that the traditional GLM method could localize43%BECTS patients well while ALFF one to N method could localize43%BECTS patients well. However, ALFF method could localize53%BECTS patients who had no IED during the experiments.Conclusions:This study localized the abnormal functional brain area using the ALFF one to N method. The results showed that the ALFF one to N method was consistent with the GLM method. In addition, ALFF one to N method could localize the epileptic foci for patients who had no IED during the experiments.