Preoperative Epilepsy Network Distribution Correlates With Seizure Recurrence Following Epilepsy Surgery

Abstract INTRODUCTION Surgery remains an essential option for the treatment of medically intractable temporal lobe epilepsy. However, only 66% of patients achieve postoperative seizure freedom, perhaps attributable to an incomplete understanding of brain network alterations in surgical candidates. Here, we present a novel network modeling algorithm that may be used to identify key characteristics of epileptic networks correlated with improved surgical outcome. METHODS Twenty-nine patients were prospectively included, and relevant demographic information was attained. Resting-state functional magnetic resonance imaging (MRI) and electroencephalography (EEG) data were recorded and preprocessed. Using our novel algorithm, patient-specific epileptic networks were mapped preoperatively and geographic spread was quantified. Global functional connectivity was also determined using a volumetric functional atlas. Key demographic data and features of epileptic networks were then correlated with surgical outcome using Pearson's product-moment correlation. RESULTS At an average follow-up of 19 mo, 20/29 (69%) patients were seizure-free. Higher rates of seizure recurrence correlated with the localization of the epilepsy network to either temporal lobe (R = –0.415, P = .039), with the stronger correlation found with the localization to the contralateral temporal lobe (R = –0.566, P = .003). When the volumetric functional atlas connectivity was measured, increased connectivity globally was correlated with seizure recurrence (R = –0.541, P = .006). Seizure recurrence also correlated with greater atlas-based connectivity within the contralateral hemisphere (R = –0.390, P = .049). CONCLUSION Network localization to the temporal lobes, in particular the contralateral temporal lobe, and increased atlas-defined connectivity contralateral to the surgery side are associated with seizure recurrence. These findings may reflect network-level disruption that has infiltrated the contralateral temporal lobe contributing to relatively worse surgical outcomes. Further identification of network parameters that predict patient outcomes may aid in patient selection, resection planning, and ultimately the efficacy of epilepsy surgery.

Download Full-text

Structural brain network abnormalities and the probability of seizure recurrence after epilepsy surgery

Neurology ◽

10.1212/wnl.0000000000011315 ◽

2020 ◽

pp. 10.1212/WNL.0000000000011315

Author(s):

Nishant Sinha ◽

Yujiang Wang ◽

Nádia Moreira da Silva ◽

Anna Miserocchi ◽

Andrew W. McEvoy ◽

...

Keyword(s):

Temporal Lobe ◽

Clinical Data ◽

Structural Mri ◽

Brain Network ◽

Patient Specific ◽

Seizure Freedom ◽

Seizure Recurrence ◽

Post Surgery ◽

Structural Brain Network ◽

Structural Brain

Objective:We assessed pre-operative structural brain networks and clinical characteristics of patients with drug resistant temporal lobe epilepsy (TLE) to identify correlates of post-surgical seizure recurrences.Methods:We examined data from 51 TLE patients who underwent anterior temporal lobe resection (ATLR) and 29 healthy controls. For each patient, using the pre-operative structural, diffusion, and post-operative structural MRI, we generated two networks: ‘pre-surgery’ network and ‘surgically-spared’ network. Standardising these networks with respect to controls, we determined the number of abnormal nodes before surgery and expected to be spared by surgery. We incorporated these 2 abnormality measures and 13 commonly acquired clinical data from each patient in a robust machine learning framework to estimate patient-specific chances of seizures persisting after surgery.Results:Patients with more abnormal nodes had lower chance of complete seizure freedom at 1 year and even if seizure-free at 1 year, were more likely to relapse within five years. The number of abnormal nodes was greater and their locations more widespread in the surgically-spared networks of poor outcome patients than in good outcome patients. We achieved 0.84±0.06 AUC and 0.89±0.09 specificity in predicting unsuccessful seizure outcomes (ILAE3-5) as opposed to complete seizure freedom (ILAE1) at 1 year. Moreover, the model-predicted likelihood of seizure relapse was significantly correlated with the grade of surgical outcome at year-one and associated with relapses up-to five years post-surgery.Conclusion:Node abnormality offers a personalised non-invasive marker, that can be combined with clinical data, to better estimate the chances of seizure freedom at 1 year, and subsequent relapse up to 5 years after ATLR.Classification of evidence:This study provides Class II evidence that node abnormality predicts post-surgical seizure recurrence.

Download Full-text

Scalp and Intracranial EEG in Medically Intractable Extratemporal Epilepsy with Normal MRI

ISRN Neurology ◽

10.5402/2012/942849 ◽

2012 ◽

Vol 2012 ◽

pp. 1-9 ◽

Cited By ~ 14

Author(s):

Tarek Zakaria ◽

Katherine Noe ◽

Elson So ◽

Gregory D. Cascino ◽

Nicholas Wetjen ◽

...

Keyword(s):

Epilepsy Surgery ◽

Surgical Outcome ◽

Favorable Outcome ◽

Rank Test ◽

Seizure Freedom ◽

Intracranial Eeg ◽

Scalp Eeg ◽

Kaplan Meier ◽

Postoperative Seizure ◽

Beta Frequency

Purpose. To investigate EEG and SPECT in the surgical outcome of patients with normal MRI (nonlesional) and extratemporal lobe epilepsy. Methods. We retrospectively identified 41 consecutive patients with nonlesional extratemporal epilepsy who underwent epilepsy surgery between 1997 and 2007. The history, noninvasive diagnostic studies (scalp EEG, MRI, and SPECT) and intracranial EEG (iEEG) monitoring was reviewed. Scalp and iEEG ictal onset patterns were defined. The association of preoperative studies and postoperative seizure freedom was analyzed using Kaplan-Meier analysis, log-rank test, and Cox proportional hazard. Results. Thirty-six of 41 patients had adequate information with a minimum of 1-year followup. Favorable surgical outcome was identified in 49% of patients at 1 year, and 35% at 4-year. On scalp EEG, an ictal onset pattern consisting of focal beta-frequency discharge (>13–125 Hz) was associated with favorable surgical outcome (P=0.02). Similarly, a focal fast-frequency oscillation (>13–125 Hz) on iEEG at ictal onset was associated with favorable outcome (P=0.03). Discussion. A focal fast-frequency discharge at ictal onset identifies nonlesional MRI, extratemporal epilepsy patients likely to have a favorable outcome after resective epilepsy surgery.

Download Full-text

Epilepsy surgery for Rasmussen encephalitis: the UCLA experience

Journal of Neurosurgery Pediatrics ◽

10.3171/2020.4.peds2098 ◽

2020 ◽

Vol 26 (4) ◽

pp. 389-397

Author(s):

Nikhil Bellamkonda ◽

H. Westley Phillips ◽

Jia-Shu Chen ◽

Alexander M. Tucker ◽

Cassia Maniquis ◽

...

Keyword(s):

Epilepsy Surgery ◽

Outcome Data ◽

Seizure Freedom ◽

Rasmussen Encephalitis ◽

Seizure Recurrence ◽

Functional Hemispherectomy ◽

Significant Difference ◽

Seizure Relapse ◽

Drug Resistant Epilepsy ◽

Postoperative Seizure

OBJECTIVERasmussen encephalitis (RE) is a rare inflammatory neurological disorder typically involving one hemisphere and resulting in drug-resistant epilepsy and progressive neurological decline. Here, the authors present seizure outcomes in children who underwent epilepsy surgery for RE at a single institution.METHODSThe records of consecutive patients who had undergone epilepsy surgery for RE at the UCLA Mattel Children’s Hospital between 1982 and 2018 were retrospectively reviewed. Basic demographic information, seizure history, procedural notes, and postoperative seizure and functional outcome data were analyzed.RESULTSThe cohort included 44 patients, 41 of whom had sufficient data for analysis. Seizure freedom was achieved in 68%, 48%, and 22% of the patients at 1, 5, and 10 years, respectively. The median time to the first seizure for those who experienced seizure recurrence after surgery was 39 weeks (IQR 11–355 weeks). Anatomical hemispherectomy, as compared to functional hemispherectomy, was independently associated with a longer time to postoperative seizure recurrence (HR 0.078, p = 0.03). There was no statistically significant difference in postoperative seizure recurrence between patients with complete hemispherectomy and those who had less-than-hemispheric surgery. Following surgery, 68% of the patients could ambulate and 84% could speak regardless of operative intervention.CONCLUSIONSA large proportion of RE patients will have seizure relapse after surgery, though patients with anatomical hemispherectomies may have a longer time to postoperative seizure recurrence. Overall, the long-term data in this study suggest that hemispheric surgery can be seen as palliative treatment for seizures rather than a cure for RE.

Download Full-text

Shorter epilepsy duration is associated with better seizure outcome in temporal lobe epilepsy surgery

Arquivos de Neuro-Psiquiatria ◽

10.1590/0004-282x20140230 ◽

2015 ◽

Vol 73 (3) ◽

pp. 212-217 ◽

Cited By ~ 10

Author(s):

Lucas Crociati Meguins ◽

Rodrigo Antônio Rocha da Cruz Adry ◽

Sebastião Carlos da Silva-Junior ◽

Gerardo Maria de Araújo Filho ◽

Lúcia Helena Neves Marques

Keyword(s):

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

Epilepsy Surgery ◽

Surgical Outcome ◽

Seizure Control ◽

Seizure Outcome ◽

Seizure Onset ◽

Postoperative Seizure

Objective To investigate the influence of patient’s age and seizure onset on surgical outcome of temporal lobe epilepsy (TLE). Method A retrospective observational investigation performed from a cohort of patients from 2000 to 2012. Results A total of 229 patients were included. One-hundred and eleven of 179 patients (62%) were classified as Engel I in the group with < 50 years old, whereas 33 of 50 (66%) in the group with ≥ 50 years old group (p = 0.82). From those Engel I, 88 (61%) reported epilepsy duration inferior to 10 years and 56 (39%) superior to 10 years (p < 0.01). From the total of patients not seizure free, 36 (42%) reported epilepsy duration inferior to 10 years and 49 (58%) superior to 10 years (p < 0.01). Conclusion Patients with shorter duration of epilepsy before surgery had better postoperative seizure control than patients with longer duration of seizures.

Download Full-text

Node abnormality predicts seizure outcome and relates to long-term relapse after epilepsy surgery

10.1101/747725 ◽

2019 ◽

Cited By ~ 1

Author(s):

Nishant Sinha ◽

Yujiang Wang ◽

Nádia Moreira da Silva ◽

Anna Miserocchi ◽

Andrew W. McEvoy ◽

...

Keyword(s):

Temporal Lobe ◽

Clinical Data ◽

Structural Mri ◽

Brain Network ◽

Patient Specific ◽

Seizure Outcome ◽

Seizure Freedom ◽

Post Surgery ◽

Seizure Relapse ◽

Temporal Lobe Resection

AbstractObjectiveWe assessed pre-operative structural brain networks and clinical characteristics of patients with drug resistant temporal lobe epilepsy (TLE) to identify correlates of post-surgical seizure outcome at 1 year and seizure relapses up to 5 years.MethodsWe retrospectively examined data from 51 TLE patients who underwent anterior temporal lobe resection (ATLR) and 29 healthy controls. For each patient, using the pre-operative structural, diffusion, and post-operative structural MRI, we generated two networks: ‘pre-surgery’ network and ‘surgically-spared’ network. The pre-surgery network is the whole-brain network before surgery and the surgically-spared network is a subnetwork of the pre-surgery network which is expected to remain unaffected by surgery and hence present post-operatively. Standardising these networks with respect to controls, we determined the number of abnormal nodes before surgery and expected to remain after surgery. We incorporated these 2 abnormality measures and 13 commonly acquired clinical data from each patient in a robust machine learning framework to estimate patient-specific chances of seizures persisting after surgery.ResultsPatients with more abnormal nodes had lower chance of seizure freedom at 1 year and even if seizure free at 1 year, were more likely to relapse within five years. In the surgically-spared networks of poor outcome patients, the number of abnormal nodes was greater and their locations more widespread than in good outcome patients. We achieved 0.84 ± 0.06 AUC and 0.89 ± 0.09 specificity in detecting unsuccessful seizure outcomes at 1-year. Moreover, the model-predicted likelihood of seizure relapse was significantly correlated with the grade of surgical outcome at year-one and associated with relapses up-to five years post-surgery.ConclusionNode abnormality offers a personalised non-invasive marker, that can be combined with clinical data, to better estimate the chances of seizure freedom at 1 year, and subsequent relapse up to 5 years after ATLR.

Download Full-text

A historical cohort of temporal lobe surgery for medically refractory epilepsy: a systematic review and meta-analysis to guide future nonrandomized controlled trial studies

Journal of Neurosurgery ◽

10.3171/2019.4.jns183235 ◽

2020 ◽

Vol 133 (1) ◽

pp. 71-78 ◽

Cited By ~ 2

Author(s):

Anthony T. Lee ◽

John F. Burke ◽

Pranathi Chunduru ◽

Annette M. Molinaro ◽

Robert Knowlton ◽

...

Keyword(s):

Systematic Review ◽

Temporal Lobe ◽

Epilepsy Surgery ◽

Refractory Epilepsy ◽

Meta Analysis ◽

Small Sample ◽

Seizure Freedom ◽

Level I ◽

Study Designs ◽

Medically Refractory Epilepsy

OBJECTIVERecent trials for temporal lobe epilepsy (TLE) highlight the challenges of investigating surgical outcomes using randomized controlled trials (RCTs). Although several reviews have examined seizure-freedom outcomes from existing data, there is a need for an overall seizure-freedom rate estimated from level I data as investigators consider other methods besides RCTs to study outcomes related to new surgical interventions.METHODSThe authors performed a systematic review and meta-analysis of the 3 RCTs of TLE in adults and report an overall surgical seizure-freedom rate (Engel class I) composed of level I data. An overall seizure-freedom rate was also collected from level II data (prospective cohort studies) for validation. Eligible studies were identified by filtering a published Cochrane meta-analysis of epilepsy surgery for RCTs and prospective studies, and supplemented by searching indexed terms in MEDLINE (January 1, 2012–April 1, 2018). Retrospective studies were excluded to minimize heterogeneity in patient selection and reporting bias. Data extraction was independently reverified and pooled using a fixed-effects model. The primary outcome was overall seizure freedom following surgery. The historical benchmark was applied in a noninferiority study design to compare its power to a single-study cohort.RESULTSThe overall rate of seizure freedom from level I data was 72.4% (55/76 patients, 3 RCTs), which was nearly identical to the overall seizure-freedom rate of 71.7% (1325/1849 patients, 18 studies) from prospective cohorts (z = 0.134, p = 0.89; z-test). Seizure-freedom rates from level I and II studies were consistent over the years of publication (R2< 0.01, p = 0.73). Surgery resulted in markedly improved seizure-free outcomes compared to medical management (RR 10.82, 95% CI 3.93–29.84, p < 0.01; 2 RCTs). Noninferiority study designs in which the historical benchmark was used had significantly higher power at all difference margins compared to using a single cohort alone (p < 0.001, Bonferroni’s multiple comparison test).CONCLUSIONSThe overall rate of seizure freedom for temporal lobe surgery is approximately 70% for medically refractory epilepsy. The small sample size of the RCT cohort underscores the need to move beyond standard RCTs for epilepsy surgery. This historical seizure-freedom rate may serve as a useful benchmark to guide future study designs for new surgical treatments for refractory TLE.

Download Full-text

Do psychiatric comorbidities predict postoperative seizure outcome in temporal lobe epilepsy surgery?

Epilepsy & Behavior ◽

10.1016/j.yebeh.2009.01.002 ◽

2009 ◽

Vol 14 (3) ◽

pp. 529-534 ◽

Cited By ~ 57

Author(s):

Ricardo Guarnieri ◽

Roger Walz ◽

Jaime E.C. Hallak ◽

Érica Coimbra ◽

Edna de Almeida ◽

...

Keyword(s):

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

Epilepsy Surgery ◽

Seizure Outcome ◽

Psychiatric Comorbidities ◽

Postoperative Seizure

Download Full-text

Association Between Anatomical Location of Surgically Induced Lesions and Postoperative Seizure Outcome in Temporal Lobe Epilepsy

Neurology ◽

10.1212/wnl.0000000000013033 ◽

2021 ◽

pp. 10.1212/WNL.0000000000013033

Author(s):

Ezequiel Gleichgerrcht ◽

Daniel L. Drane ◽

Simon Sean Keller ◽

Kathryn A. Davis ◽

Robert Gross ◽

...

Keyword(s):

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

Anterior Commissure ◽

Piriform Cortex ◽

Seizure Outcome ◽

Seizure Freedom ◽

Anatomical Location ◽

Surgical Interventions ◽

Postoperative Seizure ◽

Promising Source

Objective:To determine the association between surgical lesions of distinct grey and white structures and connections with favorable post-operative seizure outcomes.Methods:Patients with drug-resistant temporal lobe epilepsy (TLE) from three epilepsy centers were included. We employed a voxel-based and connectome-based mapping approach to determine the association between favorable outcomes and surgery-induced temporal lesions. Analyses were conducted controlling for multiple confounders, including total surgical resection/ablation volume, hippocampal volumes, side of surgery, and site where the patient was treated.Results:The cohort included 113 patients with TLE [54 women; 86 right-handed; 16.5 (SD = 11.9) age at seizure onset, 54.9% left] who were 61.1% free of disabling seizures (Engel class 1) at follow-up. Postoperative seizure freedom in TLE was associated with 1) surgical lesions that targeted the hippocampus as well as the amygdala-piriform cortex complex and entorhinal cortices; 2) disconnection of temporal, frontal, and limbic regions through loss of white matter tracts within the uncinate fasciculus, anterior commissure, and fornix; and 3) functional disconnection of the frontal (superior and middle frontal gyri, orbitofrontal region) and temporal (superior and middle pole) lobes.Conclusions:Better postoperative seizure freedom are associated with surgical lesions of specific structures and connections throughout the temporal lobes. These findings shed light on the key components of epileptogenic networks in TLE and constitute a promising source of new evidence for future improvements in surgical interventions.Classification of Evidence:This study provides Class II evidence that for patients with temporal lobe epilepsy, postoperative seizure freedom is associated with surgical lesions of specific temporal lobe structures and connections.

Download Full-text

Surgical Outcomes and EEG Prognostic Factors After Stereotactic Laser Amygdalohippocampectomy for Mesial Temporal Lobe Epilepsy

Frontiers in Neurology ◽

10.3389/fneur.2021.654668 ◽

2021 ◽

Vol 12 ◽

Author(s):

Shasha Wu ◽

Naoum P. Issa ◽

Maureen Lacy ◽

David Satzer ◽

Sandra L. Rose ◽

...

Keyword(s):

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

Surgical Outcomes ◽

Mesial Temporal Lobe Epilepsy ◽

Seizure Freedom ◽

Seizure Recurrence ◽

Factors Associated ◽

Scalp Eeg ◽

Mesial Temporal Lobe

Objective: To assess the seizure outcomes of stereotactic laser amygdalohippocampectomy (SLAH) in consecutive patients with mesial temporal lobe epilepsy (mTLE) in a single center and identify scalp EEG and imaging factors in the presurgical evaluation that correlate with post-surgical seizure recurrence.Methods: We retrospectively reviewed the medical and EEG records of 30 patients with drug-resistant mTLE who underwent SLAH and had at least 1 year of follow-up. Surgical outcomes were classified using the Engel scale. Univariate hazard ratios were used to evaluate the risk factors associated with seizure recurrence after SLAH.Results: The overall Engel class I outcome after SLAH was 13/30 (43%), with a mean postoperative follow-up of 48.9 ± 17.6 months. Scalp EEG findings of interictal regional slow activity (IRSA) on the side of surgery (HR = 4.05, p = 0.005) and non-lateralizing or contra-lateralizing seizure onset (HR = 4.31, p = 0.006) were negatively correlated with postsurgical seizure freedom. Scalp EEG with either one of the above features strongly predicted seizure recurrence after surgery (HR = 7.13, p < 0.001) with 100% sensitivity and 71% specificity.Significance: Understanding the factors associated with good or poor surgical outcomes can help choose the best candidates for SLAH. Of the variables assessed, scalp EEG findings were the most clearly associated with seizure outcomes after SLAH.

Download Full-text