Publications by authors named "Seyed Sohrab Hashemi Fesharaki"

10 Publications

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Temporal and extratemporal atrophic manifestation of temporal lobe epilepsy using voxel-based morphometry and corticometry: clinical application in lateralization of epileptogenic zone.

Neurol Sci 2021 Jan 3. Epub 2021 Jan 3.

Physics and Biomedical Engineering Department, Tehran University of Medical Sciences, Tehran, Iran.

Background: Advances in MRI acquisition and data processing have become important for revealing brain structural changes. Previous studies have reported widespread structural brain abnormalities and cortical thinning in patients with temporal lobe epilepsy (TLE), as the most common form of focal epilepsy.

Methods: In this research, healthy control cases (n = 20) and patients with left TLE (n = 19) and right TLE (n = 14) were recruited, all underwent 3.0 T MRI with magnetization-prepared rapid gradient echo sequence to acquire T1-weighted images. Morphometric alterations in gray matter were identified using voxel-based morphometry (VBM). Volumetric alterations in subcortical structures and cortical thinning were also determined.

Results: Patients with left TLE demonstrated more prevailing and widespread changes in subcortical volumes and cortical thickness than right TLE, mainly in the left hemisphere, compared to the healthy group. Both VBM analysis and subcortical volumetry detected significant hippocampal atrophy in ipsilateral compared to contralateral side in TLE group. In addition to hippocampus, subcortical volumetry found the thalamus and pallidum bilaterally vulnerable to the TLE. Furthermore, the TLE patients underwent cortical thinning beyond the temporal lobe, affecting gray matter cortices in frontal, parietal, and occipital lobes in the majority of patients, more prevalently for left TLE cases. Exploiting volume changes in individual patients in the hippocampus alone led to 63.6% sensitivity and 100% specificity for lateralization of TLE.

Conclusion: Alteration of gray matter volumes in subcortical regions and neocortical temporal structures and also cortical gray matter thickness were evidenced as common effects of epileptogenicity, as manifested by the majority of cases in this study.
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http://dx.doi.org/10.1007/s10072-020-05003-2DOI Listing
January 2021

Dynamic functional connectivity in temporal lobe epilepsy: a graph theoretical and machine learning approach.

Neurol Sci 2020 Oct 14. Epub 2020 Oct 14.

Research Center for Molecular and Cellular Imaging, Advanced Medical Technologies and Equipment Institute (AMTEI), Tehran University of Medical Sciences, Tehran, Iran.

Purpose: Functional magnetic resonance imaging (fMRI) in resting state can be used to evaluate the functional organization of the human brain in the absence of any task or stimulus. The functional connectivity (FC) has non-stationary nature and consented to be varying over time. By considering the dynamic characteristics of the FC and using graph theoretical analysis and a machine learning approach, we aim to identify the laterality in cases of temporal lobe epilepsy (TLE).

Methods: Six global graph measures are extracted from static and dynamic functional connectivity matrices using fMRI data of 35 unilateral TLE subjects. Alterations in the time trend of the graph measures are quantified. The random forest (RF) method is used for the determination of feature importance and selection of dynamic graph features including mean, variance, skewness, kurtosis, and Shannon entropy. The selected features are used in the support vector machine (SVM) classifier to identify the left and right epileptogenic sides in patients with TLE.

Results: Our results for the performance of SVM demonstrate that the utility of dynamic features improves the classification outcome in terms of accuracy (88.5% for dynamic features compared with 82% for static features). Selecting the best dynamic features also elevates the accuracy to 91.5%.

Conclusion: Accounting for the non-stationary characteristics of functional connectivity, dynamic connectivity analysis of graph measures along with machine learning approach can identify the temporal trend of some specific network features. These network features may be used as potential imaging markers in determining the epileptogenic hemisphere in patients with TLE.
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http://dx.doi.org/10.1007/s10072-020-04759-xDOI Listing
October 2020

Graph theory application with functional connectivity to distinguish left from right temporal lobe epilepsy.

Epilepsy Res 2020 11 6;167:106449. Epub 2020 Sep 6.

Medical Physics and Biomedical Engineering Department, Tehran University of Medical Sciences(TUMS), Tehran, Iran; Research Center for Molecular and Cellular Imaging, Research Center for Science and Technology in Medicine, Tehran University of Medical Sciences (TUMS), Tehran, Iran. Electronic address:

Objective: To investigate the application of graph theory with functional connectivity to distinguish left from right temporal lobe epilepsy (TLE).

Methods: Alterations in functional connectivity within several brain networks - default mode (DMN), attention (AN), limbic (LN), sensorimotor (SMN) and visual (VN) - were examined using resting-state functional MRI (rs-fMRI). The study accrued 21 left and 14 right TLE as well as 17 nonepileptic control subjects. The local nodal degree, a feature of graph theory, was calculated foreach of the brain networks. Multivariate logistic regression analysis was performed to determine the accuracy of identifying seizure laterality based on significant differences in local nodal degree in the selected networks.

Results: Left and right TLE patients showed dissimilar patterns of alteration in functional connectivity when compared to control subjects. Compared with right TLE, patients with left TLE exhibited greater nodal degree' (i.e. hyperconnectivity) with right superomedial frontal gyrus (in DMN), inferior frontal gyrus pars triangularis (in AN), right caudate and left superior temporal gyrus (in LN) and left paracentral lobule (in SMN), while showing lesser nodal degree (i.e. hypoconnectivity) with left temporal pole (in DMN), right insula (in LN), left supplementary motor area (in SMN), and left fusiform gyrus (in VN). The LN showed the highest accuracy of 82.9% among all considered networks in determining laterality of the TLE. By combinations of local degree attributes in the DMN, AN, LN, and VN, logistic regression analysis demonstrated an accuracy of 94.3% by comparison.

Conclusion: Our study demonstrates the utility of graph theory application to brain network analysis as a potential biomarker to assist in the determination of TLE laterality and improve the confidence in presurgical decision-making in cases of TLE.
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http://dx.doi.org/10.1016/j.eplepsyres.2020.106449DOI Listing
November 2020

Distinct patterns of hippocampal subfield volume loss in left and right mesial temporal lobe epilepsy.

Neurol Sci 2021 Apr 12;42(4):1411-1421. Epub 2020 Aug 12.

Medical Physics and Biomedical Engineering Department, Tehran University of Medical Sciences (TUMS), Tehran, Iran.

Objective: To investigate the pattern and severity of hippocampal subfield volume loss in patients with left and right mesial temporal lobe epilepsy (mTLE) using quantitative MRI volumetric analysis.

Methods: A total of 21 left and 14 right mTLE subjects, as well as 15 healthy controls, were enrolled in this cross-sectional study. A publically available magnetic resonance imaging (MRI) brain volumetry system (volBrain) was used for volumetric analysis of hippocampal subfields. The T1-weighted images were processed with a HIPS pipeline.

Results: A distinct pattern of hippocampal subfield atrophy was found between left and right mTLE patients when compared with controls. Patients with left mTLE exhibited ipsilateral hippocampal atrophy and segmental volume depletion of the Cornu Ammonis (CA) 2/CA3, CA4/dentate gyrus (DG), and strata radiatum-lacunosum-moleculare (SR-SL-SM). Those with right mTLE exhibited similar ipsilateral hippocampal atrophy but with additional segmental CA1 volume depletion. More extensive bilateral subfield volume loss was apparent with right mTLE patients.

Conclusion: We demonstrate that left and right mTLE patients show a dissimilar pattern of hippocampal subfield atrophy, suggesting the pathophysiology of epileptogenesis in left and right mTLE to be different.
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http://dx.doi.org/10.1007/s10072-020-04653-6DOI Listing
April 2021

Evolution of Graph Theory in Dynamic Functional Connectivity for Lateralization of Temporal Lobe Epilepsy.

Annu Int Conf IEEE Eng Med Biol Soc 2019 Jul;2019:628-631

Resting-state functional magnetic resonance imaging (rsfMRI) has described the functional architecture of the human brain in the absence of any task or stimulus. Since the functional connectivity (FC), has non-stationary nature, it is evidenced to be varying over time. Using dynamic functional connectivity, six graph theoretical characteristics were measured and compared between left and right temporal lobe epilepsy (TLE). We also obtain a trend for each characteristic in the time course of experiments. The results demonstrated that the static connectivity analysis failed to fully separate the left and right TLE patients for some characteristics, whereby the dynamic analysis has been shown capable of identifying the laterality. Furthermore, the results suggest that the temporal trend of some graph theoretical characteristics can be exploited as a novel marker for TLE laterality.
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http://dx.doi.org/10.1109/EMBC.2019.8856717DOI Listing
July 2019

Expression Analysis of lncRNAs in Refractory and Non-Refractory Epileptic Patients.

J Mol Neurosci 2020 May 3;70(5):689-698. Epub 2020 Jan 3.

Urogenital Stem Cell Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

Long non-coding RNAs (lncRNAs) have been demonstrated to be involved in the pathogenesis of neuropsychiatric disorders such as epilepsy. In the current study, we evaluated expression of eight lncRNAs in 80 epileptic patients (40 refractory and 40 non-refractory ones) and 40 normal individual using quantitative real-time PCR. Bayesian regression model showed significant higher expression of UCA1 in both refractory and non-refractory groups compared with controls (posterior beta of relative expression (RE) = 2.03, P value = 0.003, and posterior beta of RE = 4.05, P value < 0.0001, respectively). Besides, expression of UCA1 was higher in non-refractory patients compared with refractory ones (posterior beta of RE = 2.008, P value = 0.019). When repeating statistical analyses in a gender-based manner, differences in expression of UCA1 were significant in all subgroup analyses except for male non-refractory vs. refractory subgroups analysis. Expression levels of NKILA and ANRIL were higher in both refractory and non-refractory groups compared with controls (posterior beta of RE = 1.565, P value = 0.018, and posterior beta of RE = 1.902, P value = 0.006 for NKILA; posterior beta of RE = 1.304, P value < 0.0001, and posterior beta of RE = 1.603, P value = 0.019 for ANRIL, respectively). However, expression levels of these two lncRNAs were not different between refractory and non-refractory groups. Gender-based analysis for these two lncRNAs revealed similar results except for lack of difference in ANRIL expression between male refractory group and controls. Expression of THRIL was significantly lower in both refractory and non-refractory groups compared with controls (posterior beta of RE = - 0.842, P value = 0.044 and posterior beta of RE = - 1.969, P value < 0.0001, respectively). Furthermore, expression of this lncRNA was lower in non-refractory patients compared with refractory ones (posterior beta of RE = - 1.129, P value = 0.002). However, no significant difference was detected between non-refractory and refractory patients either in males or females. The interactions between gender and relative expressions of PACER, DILC, and MALAT1 were significant, so the results were assessed in gender-based manner. In females, expression of DILC was higher in non-refractory patients compared with refractory ones (posterior beta of RE = 0.959, P value = 0.044). Expression of MALAT1 was lower in female non-refractory patients compared with controls and in female non-refractory patients compared with refractory ones (posterior beta of RE = - 1.35, P value = 0.002, and posterior beta of RE = - 0.942, P value = 0.045, respectively). Finally, expression of PACER was higher in refractory patients vs. controls and non-refractory patients vs. controls in both male and female subgroups. However, comparison between non-refractory and refractory patients revealed significant results only among females. Expression of none of the assessed lncRNAs was correlated with age of study participants. There were robust correlations between expression levels of lncRNAs. The most robust correlations were detected between UCA1 and PACER (r = 0.84, P < 0.0001) and between UCA1 and ANRIL (r = 0.75, P < 0.0001). Taken together, our study demonstrated dysregulation of lncRNAs in peripheral blood of epileptic patients and potentiated them as biomarkers for this neurologic condition.
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http://dx.doi.org/10.1007/s12031-019-01477-8DOI Listing
May 2020

Anti-NMDA Receptor Encephalitis Presenting with Status Epilepticus: Brucellosis as a Possible Triggering Factor: A Case Report.

Int J Prev Med 2019 5;10:119. Epub 2019 Jul 5.

Pars Advanced Medical Research Center, Pars Hospital, Tehran, Iran.

Brucellosis is a common zoonotic infection caused by bacterial genus , a Gram-negative bacterium, and continued to be a health problem in endemic areas. Anti--methyl-d-aspartate receptor (NMDAR) encephalitis is an autoimmune disease which can lead to status epilepticus. A 19-year-old male patient was referred to our hospital with status epilepticus. The diagnosis of brucellosis was confirmed about 2 weeks before. The brain magnetic resonance imaging was normal. Lumbar puncture was performed, and cerebral spinal fluid (CSF) was in normal limits. The patient was treated with antiepileptic, anti-brucellosis agents. Two weeks after discharge, the patient readmitted to hospital with status epilepticus again. Extensive workup was negative except that NMDAR antibodies were detected in serum and CSF. The diagnosis of anti-NMDAR encephalitis was established. Brucellosis as a triggering factor for NMDAR encephalitis should be considered.
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http://dx.doi.org/10.4103/ijpvm.IJPVM_417_18DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6639843PMC
July 2019

Component-related BOLD response to localize epileptic focus using simultaneous EEG-fMRI recordings at 3T.

J Neurosci Methods 2019 07 23;322:34-49. Epub 2019 Apr 23.

Isfahan Neurosciences Research Center, Department of Neurology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.

Background: Simultaneous EEG-fMRI experiments record spatiotemporal dynamics of epileptic activity. A shortcoming of spike-based EEG-fMRI studies is their inability to provide information about behavior of epileptic generators when no spikes are visible.

New Method: We extract time series of epileptic components identified on EEG and fit them with Generalized Linear Model (GLM) model. This allows a precise and reliable localization of epileptic foci in addition to predicting generator's behavior. The proposed method works in the source domain and delineates generators considering spatial correlation between spike template and candidate components in addition to patient's medical records.

Results: The proposed method was applied on 20 patients with refractory epilepsy and 20 age- and gender-matched healthy controls. The identified components were examined statistically and threshold of localization accuracy was determined as 86% based on Receiver Operating Characteristic (ROC) curve analysis. Accuracy, sensitivity, and specificity were found to be 88%, 85%, and 95%, respectively. Contribution of EEG-fMRI and concordance between EEG and fMRI were also evaluated. Concordance was found in 19 patients and contribution in 17.

Comparison With Existing Methods: We compared the proposed method with conventional methods. Our comparisons showed superiority of the proposed method. In particular, when epileptogenic zone was located deep in the brain, the method outperformed existing methods.

Conclusions: This study contributes substantially to increasing the yield of EEG-fMRI and presents a realistic estimate of the neural behavior of epileptic generators, to the best of our knowledge, for the first time in the literature.
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http://dx.doi.org/10.1016/j.jneumeth.2019.04.010DOI Listing
July 2019

Cardiac arrest associated with epileptic seizures: A case report with simultaneous EEG and ECG.

Epilepsy Behav Case Rep 2014 29;2:145-51. Epub 2014 Aug 29.

Shefa Neuroscience Research Center, Khatamolanbia Hospital, Tehran, Iran ; Pars Advanced Medical Research Center, Pars Hospital, Tehran, Iran.

Ictal asystole is a rare, probably underestimated manifestation of epileptic seizures whose pathophysiology is still debated. This report describes two patients who had cardiac asystole at the end of their seizure. The first patient was a 13-year-old boy with complex partial seizures.. His MRI showed symmetrical signal abnormality in the bilateral parietooccipital lobe accompanied by mild gliosis and volume loss. During a 3-day long-term video-EEG monitoring, he had cardiac arrest at the end of one of his seizures that was secondarily generalized. The second one was a 42-year-old veteran with penetrating head trauma in the left frontal lobe due to shell injury. During long-term video-EEG monitoring, he had one generalized tonic-clonic seizure accompanied by bradycardia and cardiac asystole. Asystoles could have a role in the incidence of sudden unexpected death in epilepsy (SUDEP), meaning that the presence of ictal bradycardia is a risk factor for SUDEP. In cases of epileptic cardiac dysrhythmia, prolonged simultaneous EEG/ECG monitoring may be required. Cardiological investigation should be included in epilepsy management.
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http://dx.doi.org/10.1016/j.ebcr.2014.07.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4307967PMC
February 2015

Bumetanide reduces seizure frequency in patients with temporal lobe epilepsy.

Epilepsia 2013 Jan 12;54(1):e9-12. Epub 2012 Oct 12.

Cellular and Molecular Research Center, Tehran University of Medical Sciences, Tehran, Iran.

Alterations in the balance of K-Na-2Cl cotransporter (NKCC1) and Na-Cl cotransporter (KCC2) activity may cause depolarizing effect of γ-aminobutyric Acid (GABA), and contribute to epileptogenesis in human temporal lobe epilepsy. NKCC1 facilitates accumulation of chloride inside neurons and favors depolarizing responses to GABA. In the current pilot study we provide the first documented look at efficacy of bumetanide, a specific NKCC1 antagonist, on reduction of seizure frequency in adult patients with temporal lobe epilepsy. According to our results, seizure frequency was reduced considerably in these patients. Furthermore, epileptiform discharges decreased in two of our patients. If the efficacy of bumetanide is proven in large scale studies, it can be used as a supplemental therapy in temporal lobe epilepsy.
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http://dx.doi.org/10.1111/j.1528-1167.2012.03654.xDOI Listing
January 2013