Long-term seizure and psychosocial outcomes of epilepsy surgery

Non-invasive measurements of ictal and interictal epileptiform activity using optically pumped magnetometers

Magneto- and electroencephalography (MEG/EEG) are important techniques for the diagnosis and pre-surgical evaluation of epilepsy. Yet, in current cryogen-based MEG systems the sensors are offset from the scalp, which limits the signal-to-noise ratio (SNR) and thereby the sensitivity to activity from deep structures such as the hippocampus. This effect is amplified in children, for whom adult-sized fixed-helmet systems are typically too big. Moreover, ictal recordings with fixed-helmet systems are problematic because of limited movement tolerance and/or logistical considerations. Optically Pumped Magnetometers (OPMs) can be placed directly on the scalp, thereby improving SNR and enabling recordings during seizures. We aimed to demonstrate the performance of OPMs in a clinical population. Seven patients with challenging cases of epilepsy underwent MEG recordings using a 12-channel OPM-system and a 306-channel cryogen-based whole-head system: three adults with known deep or weak (low SNR) sources of interictal epileptiform discharges (IEDs), along with three children with focal epilepsy and one adult with frequent seizures. The consistency of the recorded IEDs across the two systems was assessed. In one patient the OPMs detected IEDs that were not found with the SQUID-system, and in two patients no IEDs were found with either system. For the other patients the OPM data were remarkably consistent with the data from the cryogenic system, noting that these were recorded in different sessions, with comparable SNRs and IED-yields overall. Importantly, the wearability of OPMs enabled the recording of seizure activity in a patient with hyperkinetic movements during the seizure. The observed ictal onset and semiology were in agreement with previous video- and stereo-EEG recordings. The relatively affordable technology, in combination with reduced running and maintenance costs, means that OPM-based MEG could be used more widely than current MEG systems, and may become an affordable alternative to scalp EEG, with the potential benefits of increased spatial accuracy, reduced sensitivity to volume conduction/field spread, and increased sensitivity to deep sources. Wearable MEG thus provides an unprecedented opportunity for epilepsy, and given its patient-friendliness, we envisage that it will not only be used for presurgical evaluation of epilepsy patients, but also for diagnosis after a first seizure.

"Do I still have epilepsy?" Epilepsy identity 15-20 years after anterior temporal lobectomy

OBJECTIVE

Identity is a multifaceted construct, comprising personal identity (sense of being a unique individual) and social identity (the sense-of-self derived from membership of social groups). Social identity involves explicit identification with a group ("I am …") and implicit behaviors or attitudes associated with group membership. Following successful treatment with surgery, patients with epilepsy can undergo a complex and lasting change in personal identity. To date, there has been no research into postoperative social epilepsy identity (SEI). We sought to examine SEI 15-20 years post-surgery, and the relationship between SEI and satisfaction with surgery, psychosocial improvements, mood, and health-related quality of life (HRQoL).

METHODS

Thirty-two patients who underwent anterior temporal lobectomy (ATL; 19 female) were recruited, with a median follow-up of 18 years (interquartile range [IQR] = 2.5). Using a novel interactive online program, we collected data on SEI, satisfaction with surgery, and perceived psychosocial improvements, alongside standardized measures of mood (Neurological Disorders Depressio Inventory-Epilepsy; Patient Health Questionnaire-Generalised Anxiety Disorder-7 item) and HRQoL (Quality of Life in Epilepsy-31 item). Non-parametric analyses were used to analyse the data.

RESULTS

Twenty-five percent of patients were free of disabling seizures since surgery, yet 65% stated they no longer had epilepsy and >90% reported satisfaction with surgery. Explicitly discarding SEI was positively associated with HRQoL at long-term follow-up, over and above seizure outcome. Implicit SEI was expressed as (a) acceptance of epilepsy, (b) a sense of belonging to the epilepsy community, and (c) difficulty disclosing and discussing epilepsy. Difficulty disclosing and discussing epilepsy was associated with increased anxiety and lower HRQoL.

SIGNIFICANCE

At long-term follow-up, over half of our patients reported an explicit change in SEI, which could promote better HRQoL. In contrast, difficulty with disclosure of epilepsy was associated with increased anxiety and reduced HRQoL, possibly reflecting the ongoing effects of stigma. These findings highlight the importance of understanding changes in patient social identity for promoting long-term well-being after surgery.

Structural Brain Network Abnormalities and the Probability of Seizure Recurrence After Epilepsy Surgery

OBJECTIVE

We assessed preoperative structural brain networks and clinical characteristics of patients with drug-resistant temporal lobe epilepsy (TLE) to identify correlates of postsurgical seizure recurrences.

METHODS

We examined data from 51 patients with TLE who underwent anterior temporal lobe resection (ATLR) and 29 healthy controls. For each patient, using the preoperative structural, diffusion, and postoperative structural MRI, we generated 2 networks: presurgery network and surgically spared network. Standardizing 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 into a robust machine learning framework to estimate patient-specific chances of seizures persisting after surgery.

RESULTS

Patients with more abnormal nodes had a lower chance of complete seizure freedom at 1 year and, even if seizure-free at 1 year, were more likely to relapse within 5 years. The number of abnormal nodes was greater and their locations more widespread in the surgically spared networks of patients with poor outcome than in patients with good outcome. We achieved an area under the curve of 0.84 ± 0.06 and specificity of 0.89 ± 0.09 in predicting unsuccessful seizure outcomes (International League Against Epilepsy [ILAE] 3-5) as opposed to complete seizure freedom (ILAE 1) at 1 year. Moreover, the model-predicted likelihood of seizure relapse was significantly correlated with the grade of surgical outcome at year 1 and associated with relapses up to 5 years after surgery.

CONCLUSION

Node abnormality offers a personalized, noninvasive 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 postsurgical seizure recurrence.

Temporal Lobe Epilepsy Surgical Outcomes Can Be Inferred Based on Structural Connectome Hubs: A Machine Learning Study

OBJECTIVE

Medial temporal lobe epilepsy (TLE) is the most common form of medication-resistant focal epilepsy in adults. Despite removal of medial temporal structures, more than one-third of patients continue to have disabling seizures postoperatively. Seizure refractoriness implies that extramedial regions are capable of influencing the brain network and generating seizures. We tested whether abnormalities of structural network integration could be associated with surgical outcomes.

METHODS

Presurgical magnetic resonance images from 121 patients with drug-resistant TLE across 3 independent epilepsy centers were used to train feed-forward neural network models based on tissue volume or graph-theory measures from whole-brain diffusion tensor imaging structural connectomes. An independent dataset of 47 patients with TLE from 3 other epilepsy centers was used to assess the predictive values of each model and regional anatomical contributions toward surgical treatment results.

RESULTS

The receiver operating characteristic area under the curve based on regional betweenness centrality was 0.88, significantly higher than a random model or models based on gray matter volumes, degree, strength, and clustering coefficient. Nodes most strongly contributing to the predictive models involved the bilateral parahippocampal gyri, as well as the superior temporal gyri.

INTERPRETATION

Network integration in the medial and lateral temporal regions was related to surgical outcomes. Patients with abnormally integrated structural network nodes were less likely to achieve seizure freedom. These findings are in line with previous observations related to network abnormalities in TLE and expand on the notion of underlying aberrant plasticity. Our findings provide additional information on the mechanisms of surgical refractoriness. ANN NEUROL 2020;88:970-983.

A patient-centered approach to understanding long-term psychosocial adjustment and meaning-making, 15 to 20 years after epilepsy surgery

OBJECTIVE

Different psychosocial trajectories have been identified following treatment with epilepsy surgery, as patients adjust to possible changes in seizure frequency and the subsequent impact on their psychosocial functioning. Qualitative research has been key to understanding this adjustment process, particularly in the short-term (2-5 years). Currently, however, there is a lack of qualitative research examining longer-term (>15 years) outcomes, precluding the same rich, detailed understanding of longer-term psychosocial outcomes. Using a grounded theory approach, we explored how patients reflected on and made sense of their adjustment trajectories, 15 to 20 years after surgery. This included the impact of surgery on their sense of self and broader psychosocial functioning.

METHODS

We recruited 40 adult patients who had undergone anterior temporal lobectomy (ATL) 15 to 20 years ago (24 females; 26 left-sided). Median age at habitual seizure onset was 9.7 years (Interquartile range; IQR = 13.8), and at surgery was 31 years (IQR = 12). Median length of follow-up was 18.4 years (IQR = 4.3). Comprehensive one-on-one interviews (median time = 86 min, IQR = 28) were used to elicit patient experiences of their surgery and subsequent psychosocial outcomes. Data were analyzed using a grounded theory inductive-deductive process.

RESULTS

Patient narratives revealed a common process of psychosocial change and meaning-making triggered by surgery, which was often perceived as a major turning point in life. Patients reflected on moving through an early postsurgical period (<5 years) of upheaval and psychological disequilibrium. While this period was often remembered as stressful, difficulties were softened and/or reframed in hindsight. Through this process of reframing and meaning-making, patients were able to reestablish equilibrium and a sense of normality. Differences were evident in how patients navigated the process of meaning-making, and the extent to which they felt surgery had changed their self-identity.

DISCUSSION

We propose a model of postsurgical meaning-making, evident in the narratives of patients who have undergone ATL, providing a new perspective on long-term psychosocial outcomes. This model contributes to our understanding of patient well-being and quality of life, by acknowledging the active role that patients play in seeking to create their own sense of normality after epilepsy surgery.

Deep learning applied to whole-brain connectome to determine seizure control after epilepsy surgery

OBJECTIVE

We evaluated whether deep learning applied to whole-brain presurgical structural connectomes could be used to predict postoperative seizure outcome more accurately than inference from clinical variables in patients with mesial temporal lobe epilepsy (TLE).

METHODS

Fifty patients with unilateral TLE were classified either as having persistent disabling seizures (SZ) or becoming seizure-free (SZF) at least 1 year after epilepsy surgery. Their presurgical structural connectomes were reconstructed from whole-brain diffusion tensor imaging. A deep network was trained based on connectome data to classify seizure outcome using 5-fold cross-validation.

RESULTS

Classification accuracy of our trained neural network showed positive predictive value (PPV; seizure freedom) of 88 ± 7% and mean negative predictive value (NPV; seizure refractoriness) of 79 ± 8%. Conversely, a classification model based on clinical variables alone yielded <50% accuracy. The specific features that contributed to high accuracy classification of the neural network were located not only in the ipsilateral temporal and extratemporal regions, but also in the contralateral hemisphere.

SIGNIFICANCE

Deep learning demonstrated to be a powerful statistical approach capable of isolating abnormal individualized patterns from complex datasets to provide a highly accurate prediction of seizure outcomes after surgery. Features involved in this predictive model were both ipsilateral and contralateral to the clinical foci and spanned across limbic and extralimbic networks.

Psychosocial outcome in epilepsy after extratemporal surgery

OBJECTIVE

Only limited data exist on psychosocial long-term outcome after epilepsy surgery in patients with extratemporal epilepsy. The aim of this study was to investigate psychosocial outcome after extratemporal epilepsy surgery and to assess factors predicting favorable outcome.

METHOD

Sixty-five out of 104 eligible patients who had undergone extratemporal epilepsy surgery at our epilepsy center between 1990 and 2015 (mean age: 42.2. years; 75% of the resections in the frontal lobe) completed a questionnaire asking about seizure status, employment status, marital and living situation, driving status, depressive symptoms, and quality of life (QOL). Follow-up was on average 9.2years after surgery (range: 1-26years).

RESULTS

Thirty-eight (58%) patients were free of disabling seizures (Engel class I), and 28 (43%) have not experienced any seizures after surgery (Engel class IA). Employment rate in the primary labor market remained at 45%, but more patients lost employment (14%) than gained employment (8%). Postoperative employment was predicted by preoperative employment (p=.007), seizure freedom (p=.025), older age at seizure onset (p=.018), younger age at follow-up (p=.035), and female gender (p=.048). Seizure-free patients were more likely to be driving; have a partner, particularly in males; and have lower depressive scores. Quality of life at follow-up was best predicted by employment (p=.012), partnership (p=.025), and seizure freedom (p=.025). In contrast, recurrence of seizures and early seizure onset were associated with poor psychosocial outcome, particularly in men.

CONCLUSION

The study provides support that extratemporal surgery can lead to improved QOL and favorable psychosocial outcome. Seizure freedom is important but not the only determinant of good psychosocial outcome.

Socioeconomic outcome of epilepsy surgery: A controlled national study

PURPOSE

Epilepsy surgery has been a standard treatment for refractory epilepsies that cannot be controlled by standard medical treatment. We aimed to evaluate the health and social consequences of resective surgery relative to controls from a study of national data.

METHODS

Using the Danish National Patient Registry we identified all subjects with an epilepsy diagnosis between 1996 and 2009 and compared them with a group of patients with an epilepsy diagnosis who had had neither epilepsy surgery nor a vagus stimulation diagnosis by the index date, and who were matched by gender, index year for epilepsy diagnosis, and index year for epilepsy surgery. We considered all the health and social information available in the Danish health, medication and social registers. The duration of follow-up was three years.

RESULTS

254 epilepsy patients and 989 controls were analyzed. Surgery patients were more severely affected by their disease as indicated by health care use and social impact before the surgical procedure. Patients who underwent epilepsy surgery had a significantly lower costs associated with the use of medication, outpatient services, inpatient admissions, and accident and emergency visits after surgery. The surgical intervention had no significant effects on social status in terms of occupation and educational level.

CONCLUSION

Although epilepsy surgery was followed by a reduction in inpatient and outpatient health care use, medication and use of accident and emergency facilities, suggesting a positive effect on the epileptic disease, there was no significant effect on social outcome measures.

The brain connectome as a personalized biomarker of seizure outcomes after temporal lobectomy

OBJECTIVE

We examined whether individual neuronal architecture obtained from the brain connectome can be used to estimate the surgical success of anterior temporal lobectomy (ATL) in patients with temporal lobe epilepsy (TLE).

METHODS

We retrospectively studied 35 consecutive patients with TLE who underwent ATL. The structural brain connectome was reconstructed from all patients using presurgical diffusion MRI. Network links in patients were standardized as Z scores based on connectomes reconstructed from healthy controls. The topography of abnormalities in linkwise elements of the connectome was assessed on subnetworks linking ipsilateral temporal with extratemporal regions. Predictive models were constructed based on the individual prevalence of linkwise Z scores >2 and based on presurgical clinical data.

RESULTS

Patients were more likely to achieve postsurgical seizure freedom if they exhibited fewer abnormalities within a subnetwork composed of the ipsilateral hippocampus, amygdala, thalamus, superior frontal region, lateral temporal gyri, insula, orbitofrontal cortex, cingulate, and lateral occipital gyrus. Seizure-free surgical outcome was predicted by neural architecture alone with 90% specificity (83% accuracy), and by neural architecture combined with clinical data with 94% specificity (88% accuracy).

CONCLUSIONS

Individual variations in connectome topography, combined with presurgical clinical data, may be used as biomarkers to better estimate surgical outcomes in patients with TLE.

Volumetric brain analysis in neurosurgery: Part 3. Volumetric CT analysis as a predictor of seizure outcome following temporal lobectomy

OBJECT

The incidence of temporal lobe epilepsy (TLE) due to mesial temporal sclerosis (MTS) can be high in developing countries. Current diagnosis of MTS relies on structural MRI, which is generally unavailable in developing world settings. Given widespread effects on temporal lobe structure beyond hippocampal atrophy in TLE, the authors propose that CT volumetric analysis can be used in patient selection to help predict outcomes following resection.

METHODS

Ten pediatric patients received preoperative CT scans and temporal resections at the CURE Children's Hospital of Uganda. Engel classification of seizure control was determined 12 months postoperatively. Temporal lobe volumes were measured from CT and from normative MR images using the Cavalieri method. Whole brain and fluid volumes were measured using particle filter segmentation. Linear discrimination analysis (LDA) was used to classify seizure outcome by temporal lobe volumes and normalized brain volume.

RESULTS

Epilepsy patients showed normal to small brain volumes and small temporal lobes bilaterally. A multivariate measure of the volume of each temporal lobe separated patients who were seizure free (Engel Class IA) from those with incomplete seizure control (Engel Class IB/IIB) with LDA (p<0.01). Temporal lobe volumes also separate normal subjects, patients with Engel Class IA outcomes, and patients with Class IB/IIB outcomes (p<0.01). Additionally, the authors demonstrated that age-normalized whole brain volume, in combination with temporal lobe volumes, may further improve outcome prediction (p<0.01).

CONCLUSIONS

This study shows strong evidence that temporal lobe and brain volume can be predictive of seizure outcome following temporal lobe resection, and that volumetric CT analysis of the temporal lobe may be feasible in lieu of structural MRI when the latter is unavailable. Furthermore, since the authors' methods are modality independent, these findings suggest that temporal lobe and normative brain volumes may further be useful in the selection of patients for temporal lobe resection when structural MRI is available.

Reducing versus stopping antiepileptic medications after temporal lobe surgery

Objective

To study the safety of antiepileptic drug (AED) withdrawal after temporal lobe epilepsy (TLE) surgery.

Methods

We reviewed patients who underwent TLE surgery from 1995 to 2011, collecting data on doses, dates of AED initiation, reduction, and discontinuation. Predictors of seizure outcome were defined using Cox-proportional hazard modeling and adjusted for, while comparing longitudinal seizure-freedom in patients for whom AEDs were unchanged after resection as opposed to reduced or stopped.

Results

A total of 609 patients (86% adults) were analyzed. Follow-up ranged from 0.5 to 16.7 years. Most (64%) had hippocampal sclerosis. Overall, 229 patients had remained on their same baseline AEDs, while 380 patients stopped (127 cases) or reduced (253 cases) their AEDs. Mean timing of the earliest AED change was shorter in patients with recurrent seizures (1.04 years) compared to those seizure-free at last follow-up (1.44 years; P-value 0.03). Whether AEDs were withdrawn 12 or 24 months after surgery, there was a 10–25% higher risk of breakthrough seizures within the subsequent 2 years. However, 70% of patients with seizure recurrence after AED discontinuation reachieved remission, as opposed to 50% of those whose seizures recurred while reducing AEDs (P = 0.0001). Long-term remission rates were similar in both AED discontinuation and “unchanged” groups (82% remission for AEDs withdrawn after 1 year and 90% for AEDs withdrawn after 2 years), while only 65% of patients whose recurrences started during AED reduction achieved a 2-year remission by last follow-up.

Interpretation

AED withdrawal increases the short-term risk of breakthrough seizures after TLE surgery, and may alter the long-term disease course in some patients.

Long-term outcome and predictors of resective surgery prognosis in patients with refractory extratemporal epilepsy

PURPOSE

We analyzed the long-term postoperative outcome and possible predictive factors of the outcome in surgically treated patients with refractory extratemporal epilepsy.

METHODS

We retrospectively analyzed 73 patients who had undergone resective surgery at the Epilepsy Center Brno between 1995 and 2010 and who had reached at least 1 year outcome after the surgery. The average age at surgery was 28.3±11.4 years. Magnetic resonance imaging (MRI) did not reveal any lesion in 24 patients (32.9%). Surgical outcome was assessed annually using Engel's modified classification until 5 years after surgery and at the latest follow-up visit.

RESULTS

Following the surgery, Engel Class I outcome was found in 52.1% of patients after 1 year, in 55.0% after 5 years, and in 50.7% at the last follow-up visit (average 6.15±3.84 years). Of the patients who reached the 5-year follow-up visit (average of the last follow-up 9.23 years), 37.5% were classified as Engel IA at each follow-up visit. Tumorous etiology and lesions seen in preoperative MRI were associated with significantly better outcome (p=0.035; p<0.01). Postoperatively, 9.6% patients had permanent neurological deficits.

CONCLUSION

Surgical treatment of refractory extratemporal epilepsy is an effective procedure. The presence of a visible MRI-detected lesion and tumorous etiology is associated with significantly better outcome than the absence of MRI-detected lesion or other etiology.

Psychosocial status 10 years after temporal lobe resection for epilepsy, a longitudinal controlled study

Knowledge about long-term psychosocial outcome of temporal lobe resection (TLR) for epilepsy is limited. The aims of this study were to describe vocational outcome 10 years after TLR and to analyze the effect on the vocational situation by seizures, laterality of resection, verbal memory, and mood. Fifty-one patients were prospectively followed 10 years after TLR. Psychosocial and neuropsychological data were ascertained at baseline and 10 years after surgery and at corresponding time points for 23 controls. Fewer patients worked 10 years post-operatively compared with controls (TLR patients: 61% and controls: 96%). However, seizure-free patients were more likely to retain employment (71%) than patients who had seizures (41%). The odds of working full-time were 9.5 times higher for patients with seizure freedom than for those with continuing seizures. There were no associations between working at 10 years and side of resection or mood, and impairment of verbal memory did not have an influence on vocational outcome.

Long term outcome in patients not initially seizure free after resective epilepsy surgery

PURPOSE

To assess the long-term seizure outcome and find predictors of outcome for patients who were not initially seizure free 6 months after epilepsy surgery.

METHODS

We retrospectively reviewed all adult patients who underwent epilepsy surgery at the Epilepsy Center Bethel, between 1992 and 2003. There were 266 patients included in this analysis.

RESULTS

Of the 266 patients who were included in this study, the probability of becoming seizure free was 12% (95%CI 8-16%) after 2 years, 19.5% (95%CI 15-24%) after 5 years and 34.7% (95%CI 28-41%) after 10 years. In patients who had auras only, the probability of being seizure free was 18.2% after 2 years, 25.5% after 5 years, and 39.1% after 10 years. In the multiregression analysis, the EEG carried out 2 years after surgery, a psychic aura, the frequency of postoperative focal seizures and hypermotor seizures predicted seizure remission in the long-term outcome.

CONCLUSIONS

The frequency and type of postoperative seizures are critical determinants for long-term outcome. Seizure semiology may be the clue to a precise diagnosis and long-term prognosis of epilepsy.

Selecting patients for epilepsy surgery: synthesis of data

The consideration of epilepsy surgery for those with medically refractory seizure disorders requires a well-functioning multidisciplinary team and a systematic approach to investigations, with the aim of advising patients of their chances of being seizure free following surgery, and the risks of any procedure. Investigatory pathways may be outlined that cover most clinical situations, and the indications for invasive EEG studies. It is crucial that patients and their families are given realistic expectations of what may, and may not, be achieved with surgical treatment, and that long-term follow-up is maintained post-operatively.

Effectiveness of the use of an omega 3 and omega 6 combination(EquazenTM) in paediatric patients with refractory epilepsy

INTRODUCTION: Epilepsy is considered a health problem. 85% of patients are satisfactorily controlled with antiepileptic drugs (AEDs) and 15% have refractory seizures. The combination of omega 3 and omega 6 fatty acids (EquazenTM) can contribute to changes in ionic currents and to stabilization of neurotransmitter's function resulting in cell membrane equilibrium. These changes lead to potential seizure control. OBJECTIVE: To compare efficacy and safety in the treatment of refractory epilepsy with a supplement combining EPA, DHA (omega 3 fatty acids) and GLA (omega 6 fatty acids). METHODS: We reviewed patients from the Neurology Department of the Children's Hospital of Mexico who have refractory epilepsy, evaluating clinical characteristics of seizures, number of seizures and AEDs. 792 mg of EPA, DHA and GLA per day (6 capsules of EquazenTM) were administrated for four weeks in order to assess the frequency of seizures as well as tolerability and probable side effects. RESULTS: The study was conducted with a total of 13 patients with follow-up four weeks after the start of supplementation. We obtained a satisfactory clinical response with ≥ 80% decrease in the daily number of seizures in more than 60% of patient. The mean of number of seizures over all patients was reduced significantly from 26.61±37.2 to 5.92 daily. In addition a significant improvement in the neurocognitive capacity was observedin all patients. CONCLUSION: The co-adjuvant supplementation with EquazenTM may result in a reduction of the number of seizures in refractory epilepsy having in addition significant impact on neurocognitive aspects. To enhance the quality of life of epileptic patient supplementation with a specific combination of EPA, DHA and GLA should be reconsidered.