Long-term Outcome of Resective Epilepsy Surgery in Patients With Lennox-Gastaut Syndrome

A comprehensive systematic literature review of the burden of illness of Lennox-Gastaut syndrome on patients, caregivers, and society

Fully elucidating the burden that Lennox-Gastaut syndrome (LGS) places on individuals with the disease and their caregivers is critical to improving outcomes and quality of life (QoL). This systematic literature review evaluated the global burden of illness of LGS, including clinical symptom burden, care requirements, QoL, comorbidities, caregiver burden, economic burden, and treatment burden (PROSPERO ID: CRD42022317413). MEDLINE, Embase, and the Cochrane Library were searched for articles that met predetermined criteria. After screening 1442 deduplicated articles and supplementary manual searches, 113 articles were included for review. A high clinical symptom burden of LGS was identified, with high seizure frequency and nonseizure symptoms (including developmental delay and intellectual disability) leading to low QoL and substantial care requirements for individuals with LGS, with the latter including daily function assistance for mobility, eating, and toileting. Multiple comorbidities were identified, with intellectual disorders having the highest prevalence. Although based on few studies, a high caregiver burden was also identified, which was associated with physical problems (including fatigue and sleep disturbances), social isolation, poor mental health, and financial difficulties. Most economic analyses focused on the high direct costs of LGS, which arose predominantly from medically treated seizure events, inpatient costs, and medication requirements. Pharmacoresistance was common, and many individuals required polytherapy and treatment changes over time. Few studies focused on the humanistic burden. Quality concerns were noted for sample representativeness, disease and outcome measures, and reporting clarity. In summary, a high burden of LGS on individuals, caregivers, and health care systems was identified, which may be alleviated by reducing the clinical symptom burden. These findings highlight the need for a greater understanding of and better definitions for the broad spectrum of LGS symptoms and development of treatments to alleviate nonseizure symptoms.

Neurostimulation for Generalized Epilepsy: Should Therapy be Syndrome-specific?

Current applications of neurostimulation for generalized epilepsy use a one-target-fits-all approach that is agnostic to the specific epilepsy syndrome and seizure type being treated. The authors describe similarities and differences between the 2 "archetypes" of generalized epilepsy-Lennox-Gastaut syndrome and Idiopathic Generalized Epilepsy-and review recent neuroimaging evidence for syndrome-specific brain networks underlying seizures. Implications for stimulation targeting and programming are discussed using 5 clinical questions: What epilepsy syndrome does the patient have? What brain networks are involved? What is the optimal stimulation target? What is the optimal stimulation paradigm? What is the plan for adjusting stimulation over time?

Epilepsy Surgery for Cognitive Improvement in Epileptic Encephalopathy

Epileptic encephalopathies are defined by the presence of frequent epileptiform activity that causes neurodevelopmental slowing or regression. Here, we review evidence that epilepsy surgery improves neurodevelopment in children with epileptic encephalopathies. We describe an example patient with epileptic encephalopathy without drug refractory seizures, who underwent successful diagnostic and therapeutic surgeries. In patients with epileptic encephalopathy, cognitive improvement alone is a sufficient indication to recommend surgical intervention in experienced centers.

Creating rare epilepsy cohorts using keyword search in electronic health records

OBJECTIVE

Administrative codes to identify people with rare epilepsies in electronic health records are limited. The current study evaluated the use of keyword search as an alternative method for rare epilepsy cohort creation using electronic health records data.

METHODS

Data included clinical notes from encounters with International Classification of Diseases, Ninth Revision (ICD-9) codes for seizures, epilepsy, and/or convulsions during 2010-2014, across six health care systems in New York City. We identified cases with rare epilepsies by searching clinical notes for keywords associated with 33 rare epilepsies. We validated cases via manual chart review. We compared the performance of keyword search to manual chart review using positive predictive value (PPV), sensitivity, and F-score. We selected an initial combination of keywords using the highest F-scores.

RESULTS

Data included clinical notes from 77 924 cases with ICD-9 codes for seizures, epilepsy, and/or convulsions. The all-keyword search method identified 6095 candidates, and manual chart review confirmed that 2068 (34%) had a rare epilepsy. The initial combination method identified 1862 cases with a rare epilepsy, and this method performed as follows: PPV median = .64 (interquartile range [IQR] = .50-.81, range = .20-1.00), sensitivity median = .93 (IQR = .76-1.00, range = .10-1.00), and F-score median = .71 (IQR = .63-.85, range = .18-1.00). Using this method, we identified four cohorts of rare epilepsies with over 100 individuals, including infantile spasms, Lennox-Gastaut syndrome, Rett syndrome, and tuberous sclerosis complex. We identified over 50 individuals with two rare epilepsies that do not have specific ICD-10 codes for cohort creation (epilepsy with myoclonic atonic seizures, Sturge-Weber syndrome).

SIGNIFICANCE

Keyword search is an effective method for cohort creation. These findings can improve identification and surveillance of individuals with rare epilepsies and promote their referral to specialty clinics, clinical research, and support groups.

Deep Brain Stimulation of the Centromedian Nucleus of the Thalamus for Lennox-Gastaut Syndrome: A Systematic Review and Individual Patient Data Analysis

BACKGROUND

Lennox-Gastaut syndrome (LGS) is a severe childhood-onset pharmacoresistant epilepsy. Deep brain stimulation (DBS) of the centromedian nucleus of the thalamus (CMN) has been utilized.

OBJECTIVE

To conduct a systematic review and individual patient data (IPD) analysis to characterize outcomes of DBS of CMN in LGS.

METHODS

PubMed, Embase, and Scopus were searched per Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Articles were screened by title/abstract then full text. Included articles were reviewed for bibliographic, demographic, and outcome data. IPD were extracted from studies providing IPD for all patients.

RESULTS

Of 72 resultant articles, 10 studies (114 patients) were included. Six of 7 studies reporting the outcome of ≥50% seizure reduction indicated that ≥50% of patients achieved this, with improved functional ability. Seizure freedom rate was generally <10%. Six studies with 47 patients provided IPD. The mean ages at epilepsy onset and CMN DBS were 3.9 ± 4.5 years and 17.4 ± 8.8 years, respectively. Nineteen of 41 (46.3%) patients had positive MRI findings. Seizure types included atypical absence in 39 (83.0%) patients, generalized tonic-clonic in 32 (68.1%), tonic in 22 (46.8%), and atonic in 20 (42.6%). Thirty-eight (80.9%) patients experienced ≥50% reduction in seizure frequency, and only 3 (6.4%) experienced seizure freedom. The mean seizure reduction was 62.9% ± 31.2% overall. Quality of life improved in 30/34 (88.2%) and was unchanged in the remainder (11.8%). The complication rate was 2/41 (4.9%). The mean length of follow-up was 19.8 ± 26.1 months (IQR: 4-18 months).

CONCLUSION

Limited data indicate that DBS of the CMN may be effective and safe for people with LGS.

Frontoparietal 18F-FDG-PET hypo-metabolism in Lennox-Gastaut syndrome: further evidence highlighting the key network

INTRODUCTION

Lennox Gastaut syndrome (LGS) can be conceptualised as a "secondary network epilepsy", in which the shared electroclinical manifestations reflect epileptic recruitment of a common brain network, despite a range of underlying aetiologies. We aimed to identify the key networks recruited by the epileptic process of LGS using interictal 2-deoxy-2-(¹⁸F)fluoro-D-glucose positron emission tomography (¹⁸F-FDG-PET).

METHODS

Group analysis of cerebral ¹⁸F-FDG-PET, comparing 21 patients with LGS (mean age = 15 years) and 18 pseudo-controls (mean age = 19 years), studied at Austin Health Melbourne, between 2004 and 2015. To minimise the influence of individual patient lesions in the LGS group, we only studied brain hemispheres without structural MRI abnormalities. The pseudo-control group consisted of age- and sex-matched patients with unilateral temporal lobe epilepsy, using only the hemispheres contralateral to the side of epilepsy. Voxel-wise permutation testing compared ¹⁸F-FDG-PET uptake between groups. Associations were explored between areas of altered metabolism and clinical variables (age of seizure onset, proportion of life with epilepsy, and verbal/nonverbal ability). Penetrance maps were calculated to explore spatial consistency of altered metabolic patterns across individual patients with LGS.

RESULTS

Although not always readily apparent on visual inspection of individual patient scans, group analysis revealed hypometabolism in a network of regions including prefrontal and premotor cortex, anterior and posterior cingulate, inferior parietal lobule, and precuneus (p < 0.05, corrected for family-wise error). These brain regions tended to show a greater reduction in metabolism in non-verbal compared to verbal LGS patients, although this difference was not statistically significant. No areas of hypermetabolism were detected on group analysis, although ∼25 % of individual patients showed increased metabolism (relative to pseudo-controls) in the brainstem, putamen, thalamus, cerebellum, and pericentral cortex.

DISCUSSION

Interictal hypometabolism in frontoparietal cortex in LGS is compatible with our previous EEG-fMRI and SPECT studies showing that interictal bursts of generalised paroxysmal fast activity and tonic seizures recruit similar cortical regions. This study provides further evidence that these regions are central to the electroclinical expression of LGS.

Pediatric epilepsy surgery in patients with Lennox-Gastaut syndrome after viral encephalitis

Objective

To analyse the surgical outcomes of pediatric patients with Lennox-Gastaut syndrome (LGS) secondary to viral encephalitis.

Methods

We retrospectively analyzed the data of four patients with LGS secondary to viral encephalitis who underwent surgery at the pediatric epilepsy center of Peking University First Hospital from January 2014 to December 2019. Preoperative evaluations included a detailed history, long-term video electroencephalography (VEEG), brain magnetic resonance imaging (MRI), positron emission tomography (PET) and a neuropsychological test. All patients were followed up at 1, 3, and 6 months and then yearly. The surgical outcome was evaluated according to the Engel classification.

Results

Among the four children, the surgeries were right temporo-parieto-occipital disconnection (case 1), corpus callosotomy (case 2), left temporo-parieto-occipital disconnection (case 3), and left temporal lobectomy (case 4). The pathology was gliosis secondary to viral encephalitis. The median follow-up time was 4 years (3-5 years). At the last follow-up, one case had Engel I, two cases had Engel III, and one case had Engel IV.

Conclusions

Preliminary observations shows that surgical treatment may be challenging for patients with LGS secondary to viral encephalitis. However, suitable surgical candidacy and approaches have a significant impact on the prognosis of the patients.

Development of localized interictal epileptiform discharges following vagus nerve stimulation for lennox-gastaut syndrome: a case report

Background

Lennox-gastaut syndrome (LGS) is an epileptic encephalopathy often associated with behavioral and psychiatric disorders. Vagus nerve stimulation (VNS) has been approved effective for LGS treatment. Surgical resection is also an option for LGS patients with focal pathology, offering a high probability of seizure control. However, it is challenging to accurately localize the seizure focus.

Case presentation

The case presented here is a 19-year-old male with a 16-year history of epilepsy with comorbid severe cognitive and psychiatric disorders. He was diagnosed with LGS due to generalized slow spike-wave discharges and multiple seizure types. He was treated with VNS in 2017 at the age of 15. After that, the frequency of the short tonic seizures decreased from 4–5 times per day to 2–5 times per year, and the generalized tonic–clonic seizure pattern did not recur, which had a frequency of 2–4 times per month before the surgery. In 2019, the generalized abnormal interictal epileptiform discharges changed to be localized in the right frontal–temporal lobe at the age of 17 years (2019).

Conclusions

This case report suggested that the generalized epileptiform discharges evolve into localized discharges after VNS treatment, which may help reveal the primary seizure focus for resection surgery in patients with LGS.

Treatment strategies for Lennox-Gastaut syndrome: outcomes of multimodal treatment approaches

Background

Multimodal treatment approaches are often considered for patients with Lennox-Gastaut syndrome (LGS). Creating an algorithm that can guide healthcare providers in selecting treatment options for patients with LGS remains a challenge. Herein, we assessed the long-term seizure-free and neurodevelopmental outcomes of stepwise multimodal treatment in patients with LGS.

Objective

Herein, we assess the long-term seizure-free and neurodevelopmental outcomes of stepwise multimodal treatment in patients with LGS.

Methods

We retrospectively examined the data of 371 patients with LGS who underwent stepwise multimodal treatment, including antiseizure medication (ASM) therapy, dietary therapy (DT), resective epilepsy surgery (R-ES), and palliative epilepsy surgery (P-ES). The seizure-free outcome was considered to be the effect of the final treatment according to the treatment algorithm, and the percentage of patients who remained seizure-free in each treatment group was calculated. ASM treatment, DT, R-ES, and P-ES were applied to 371 (100%), 201 (54.2%), 112 (30.2%), and 115 (31.0%) patients with LGS, respectively. We evaluated the stepwise multimodal treatment outcomes in these patients.

Results

One hundred sixty-eight patients (45.3%) remained seizure-free for at least 1 year (seizure-free-for-1-year group), 61 of whom (16.5%) remained seizure-free for more than 5 years (remained-seizure-free group). Among the patients treated with ASM therapy, DT, R-ES, and P-ES, 41 (11.1%), 53 (14.3%), 56 (15.1%), and 29 (7.8%), respectively, remained seizure-free for 1 year. In addition, 15 (4.1%), 15 (4.1%), 19 (5.1%), and 12 (3.2%) patients in the ASM, DT, R-ES, and P-ES treatment groups, respectively, remained seizure-free for more than 5 years. Both the seizure-free-for-1-year and remained-seizure-free groups showed significant improvement in electroencephalography findings and neurodevelopmental status following treatment.

Conclusion

This study provides an update on the long-term seizure outcomes and neurodevelopmental improvements in a large cohort of patients with LGS following comprehensive multimodal treatment. We emphasize that the active combination of multiple ASMs, DT, and surgical treatment could provide long-term seizure-free outcomes and significant neurological benefits to patients with LGS.

Effective application of corpus callosotomy in pediatric intractable epilepsy patients with mitochondrial dysfunction

Background:

Whether epilepsy surgery, such as corpus callosotomy is effective in patients with pediatric intractable epilepsy with mitochondrial dysfunction is controversial, and there is a paucity of literature on this issue.

Objective:

This study aimed to assess and describe the effective application of corpus callosotomy for treating pediatric patients with intractable epilepsy with mitochondrial dysfunction in a single institution in Korea.

Methods:

This was a retrospective study of pediatric patients with intractable epilepsy and mitochondrial dysfunction who underwent corpus callosotomy in a single tertiary care center. Ten patients with intractable epilepsy with mitochondrial dysfunction were included, and 10 patients with intractable epilepsy with non-mitochondrial dysfunctions were included as a control group. The outcomes of corpus callosotomy in the two groups were evaluated and compared.

Results:

Corpus callosotomy was safely performed and was efficacious in reducing seizure frequency in both groups. The group with non-mitochondrial dysfunction showed slightly better treatment outcomes, with greater reductions in overall seizures, traumatic falling seizures, and electroencephalography improvements, but the differences in treatment effects were not statistically significant.

Conclusions:

Our study is meaningful as it identified the use of corpus callosotomy as a means to save lives and improve quality of life by reducing the frequency of seizures and those associated with traumatic falling in pediatric patients with intractable epilepsy with mitochondrial dysfunction. Larger multicenter studies are necessary to confirm the efficacy of the procedure.

Epilepsy: Epileptic Syndromes and Treatment

Epilepsy can now be diagnosed even in the presence of one unprovoked seizure or if the diagnosis of an epilepsy syndrome can be made. Epilepsy syndromes represent a specific set of seizure types and electroencephalographic and imaging features that tend to have age-dependent features, triggers, and prognosis. Epilepsy syndromes are the third and final level of epilepsy diagnosis, after classification of seizure and epilepsy types. Some epilepsy syndromes are self-limiting and pharmacoresponsive and others are pharmacoresistant and associated with poor developmental outcomes (epileptic and developmental encephalopathy). Features and management of 7 common age-dependent pediatric epilepsy syndromes are described.

Vagus nerve stimulation in patients with Lennox-Gastaut syndrome: A meta-analysis

Objectives

Lennox‐Gastaut syndrome (LGS) is among the most severe epileptic and developmental encephalopathies. A meta‐analysis was performed to evaluate the effectiveness of adjunctive vagus nerve stimulation (VNS Therapy) in patients with LGS.

Materials & Methods

PubMed database was queried (January 1997 to September 2018) to identify publications reporting on the efficacy of VNS Therapy in patients with LGS, with or without safety findings. Primary endpoint of the meta‐analysis was the proportion of responders (≥50% reduction in seizure frequency). Random‐effects analysis was used to calculate weighted mean estimates and confidence intervals. Heterogeneity was evaluated by statistical tests including I².

Results

Of 2752 citations reviewed, 17 articles (480 patients) were eligible including 10 retrospective studies and seven prospective studies. A random‐effects model produced a pooled proportion of 54% (95% confidence intervals [CI]: 45%, 64%) of patients with LGS who responded to adjunctive VNS Therapy (p for heterogeneity <0.001, I²=72.9%). Per an exploratory analysis, the calculated incidence of serious adverse events associated with VNS Therapy was 9% (95% CI: 5%, 14%); the rate was higher than in long‐term efficacy studies of heterogeneous cohorts with drug‐resistant epilepsy and likely attributed to variable definitions of serious adverse events across studies.

Conclusions

The meta‐analysis of 480 patients with LGS suggests that 54% of patients responded to adjunctive VNS Therapy and that the treatment option was safe and well‐tolerated. The response in patients with LGS was comparable to heterogeneous drug‐resistant epilepsy populations. A clinical and surgical overview has been included to facilitate the use of VNS in LGS.

The role of surgery in the management of Lennox-Gastaut syndrome: A systematic review and meta-analysis of the clinical evidence

Lennox-Gastaut syndrome (LGS) is a severe form of childhood onset epilepsy in which patients require multiple medications and may be candidates for palliative surgical intervention. In this meta-analysis, we sought to evaluate the impact of palliative vagus nerve stimulation (VNS), corpus callosotomy (CC), and resective surgery (RS) by analyzing their impact on seizure control, antiepileptic drug (AED) usage, quality of life (QOL), behavior, cognition, prognostic factors, and complications. A systematic search of PubMed MEDLINE, Scopus, and Cochrane Database of Systematic Reviews was performed to find articles that met the following criteria: (1) prospective/retrospective study with original data, (2) at least one LGS surgery patient aged less than 18 years, and (3) information on seizure frequency reduction (measured as percentage, Engel class, or qualitative comment). Seizures were analyzed quantitatively in a meta-analysis of proportions and a random-effects model, whereas other outcomes were analyzed qualitatively. Forty studies with 892 LGS patients met the selection criteria, with 19 reporting on CC, 17 on VNS, four on RS, two on RS + CC, one on CC + VNS, and one on deep brain stimulation. CC seizure reduction rate was 74.1% (95% confidence interval [CI] = 64.5%-83.7%), and VNS was 54.6% (95% CI = 42.9%-66.3%), which was significantly different (p < .001). RS seizure reduction was 88.9% (95% CI = 66.1%-99.7%). Many VNS patients reported alertness improvements, and most had no major complications. VNS was most effective for atonic/tonic seizures; higher stimulation settings correlated with better outcomes. CC patients reported moderate cognitive and QOL improvements; disconnection syndrome, transient weakness, and respiratory complications were noted. Greater callosotomy extent correlated with better outcomes. AED usage most often did not change after surgery. RS showed considerable QOL improvements for patients with localized seizure foci. In the reported literature, CC appeared to be more effective than VNS for seizure reduction. VNS may provide a similar or higher level of QOL improvement with lower aggregate risk of complications. Patient selection, anatomy, and seizure type will inform decision-making.

The unchanging face of Lennox-Gastaut syndrome in adulthood

PURPOSE

Lennox-Gastaut syndrome (LGS) is a severe childhood-onset epileptic encephalopathy characterized by the presence of multiple types of intractable seizures, cognitive impairment, and specific electroencephalogram (EEG) patterns. The aim of this study was to investigate the electroclinical features of patients with LGS during adulthood.

METHODS

We retrospectively identified the medical records of 20 patients aged over 18 years with a diagnosis of LGS from 3896 patients with epilepsy.

RESULTS

Thirteen (65 %) patients were male. The mean age of the patients was 23.4 ± 7.1 (min-max; 18-43) years, and the mean follow-up period was 5.6 ± 4.5 (min-max; 1-14) years. The etiology was identified in 11 (55 %) patients. None of the patients achieved seizure freedom. The most prevalent seizure types were atypical absences in 14 (70 %) patients, tonic seizures in 13 (65 %) patients, and atonic seizures in 11 (55 %) patients. One (5 %) patient was diagnosed as having psychogenic non-epileptic seizures. Mental retardation was reported in all patients and only half of them could walk independently. All patients had drug-resistant seizures and 16 (80 %) patients were on polytherapy. A vagus nerve stimulator was implanted into ten (50 %) patients and five reported 50-80 % seizure reduction. Ketogenic diet was administered to two (10 %) patients and epilepsy surgery was performed in two (10 %) patients with no significant benefit.

CONCLUSIONS

Paying attention to all factors of seizure outcomes, cognitive impairment, and ambulatory status, all patients were dependent on caregivers for daily living abilities. LGS has life-long persistence with poor outcomes, even during adulthood.

Neuroimaging of Childhood Epilepsy: Focal versus Generalized Epilepsy

Neuroimaging plays an increasingly crucial role in delineating the pathophysiology, and guiding the evaluation, management and monitoring of epilepsy. Imaging contributes to adequately categorizing seizure/epilepsy types in complex clinical situations by demonstrating anatomical and functional changes associated with seizure activity. This article reviews the current status of multimodality neuroimaging in the pediatric population, including focal lesions which may result in focal epileptic findings, focal structural abnormalities that may manifest as generalized epileptiform discharges, and generalized epilepsy without evidence of detectable focal abnormalities.

Postoperative improvement of executive function and adaptive behavior in children with intractable epilepsy

INTRODUCTION

An alteration in postoperative cognitive function varies according to the patients' background characteristics, such as etiology, focus, and seizure duration. Accurate prediction and assessment of postoperative cognitive function is difficult in each patient. Adaptive behavior could describe the typical performance of daily activities and represents the ability to translate cognitive potential into real-world skills. We examined the relationship between alterations of executive function (EF) and adaptive behavior in school children undergoing surgery for intractable epilepsy.

METHODOLOGY

We enrolled 31 children with focal resection or corpus callosotomy for intractable epilepsy [mean age at surgery, 12.5 years; 16 boys; mean intellectual quotient, 73.3]. We surveyed answered questionnaires on attention-deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and adaptive behavior using the Vineland Adaptive Behavior Scale, 2nd edition (VABS-II), and performed continuous performance tests (CPTs) on children pre- and postoperatively.

RESULT

ADHD and ASD symptoms improved after epilepsy surgery. The omission error (OE) in the CPT variable improved after epilepsy surgery, especially in children with a shorter preoperative period. Improved ASD symptoms led to an increased score of the coping skills subdomain. The reduced OE observed after surgery also increased the score of the community skills subdomain.

CONCLUSION

Improvement in EF and ASD symptoms resulted in better adaptive behavior postoperatively. These results were important for the pre- and postoperative evaluation and re-evaluation of children with epilepsy requiring special education and related services.

Expanding the Treatment Landscape for Lennox-Gastaut Syndrome: Current and Future Strategies

Lennox-Gastaut syndrome (LGS), a childhood-onset severe developmental and epileptic encephalopathy (DEE), is an entity that encompasses a heterogenous group of aetiologies, with no single genetic cause. It is characterised by multiple seizure types, an abnormal EEG with generalised slow spike and wave discharges and cognitive impairment, associated with high morbidity and profound effects on the quality of life of patients and their families. Drug-refractory seizures are a hallmark and treatment is further complicated by its multiple morbidities, which evolve over the patient's lifetime. This review provides a comprehensive overview of the current and future options for the treatment of seizures associated with LGS. Six treatments are specifically indicated as adjunct therapies for the treatment of seizures associated with LGS in the US: lamotrigine, clobazam, rufinamide, topiramate, felbamate and most recently cannabidiol. These therapies have demonstrated reductions in drop seizures in 15%-68% of patients across trials, with responder rates (≥ 50% reduction in drop seizures) of 37%-78%. Valproate is still the preferred first-line treatment, generally in combination with lamotrigine or clobazam. Other treatments frequently used off-label include the broad spectrum anti-epileptic drugs (AED) levetiracetam, zonisamide and perampanel, while recent evidence from observational studies has indicated that a newer AED, the levetiracetam analogue brivaracetam, may be effective and well tolerated in LGS patients. Other treatments in clinical development include fenfluramine in late phase III, perampanel, soticlestat-OV953/TAK-953, carisbamate and ganaxolone. Non-pharmacologic interventions include the ketogenic diet, vagus nerve stimulation and surgical interventions; these are also expanding, with the potential for less invasive techniques for corpus callosotomy that have promise for reducing complications. However, despite these advancements, patients continue to experience a significant burden. Because LGS is not a single entity, tailoring of treatment is needed as opposed to a 'one size fits all' approach. Further research is needed into the underlying aetiologies and pathophysiology of LGS, together with advancements in treatments that encompass the spectrum of seizures associated with this complex syndrome.

Combined Isoflurane-Remifentanil Anaesthesia Permits Resting-State fMRI in Children with Severe Epilepsy and Intellectual Disability

Head motion is a significant barrier to functional MRI (fMRI) in patients who are unable to tolerate awake scanning, including young children or those with cognitive and behavioural impairments. General anaesthesia minimises motion and ensures patient comfort, however the optimal anaesthesia regimen for fMRI in the paediatric setting is unknown. In this study, we tested the feasibility of anaesthetised fMRI in 11 patients (mean age = 9.8 years) with Lennox-Gastaut syndrome, a severe form of childhood-onset epilepsy associated with intellectual disability. fMRI was acquired during clinically-indicated MRI sessions using a synergistic anaesthesia regimen we typically administer for epilepsy neurosurgery: combined low-dose isoflurane (≤ 0.8% end-tidal concentration) with remifentanil (≤ 0.1 mcg/kg/min). Using group-level independent component analysis, we assessed the presence of resting-state networks by spatially comparing results in the anaesthetised patients to resting-state network templates from the 'Generation R' study of 536 similarly-aged non-anaesthetised healthy children (Muetzel et al. in Hum Brain Mapp 37(12):4286-4300, 2016). Numerous resting-state networks commonly studied in non-anaesthetised healthy children were readily identifiable in the anaesthetised patients, including the default-mode, sensorimotor, and frontoparietal networks. Independent component time-courses associated with these networks showed spectral characteristics suggestive of a neuronal origin of fMRI signal fluctuations, including high dynamic range and temporal frequency power predominantly below 0.1 Hz. These results demonstrate the technical feasibility of anaesthetised fMRI in children, suggesting that combined isoflurane-remifentanil anaesthesia may be an effective strategy to extend the emerging clinical applications of resting-state fMRI (for example, neurosurgical planning) to the variety of patient groups who may otherwise be impractical to scan.

Intractable Generalized Epilepsy: Therapeutic Approaches

PURPOSE OF REVIEW

To summarize recent developments in therapeutic options, both medical and surgical, for patients with drug-resistant generalized epilepsy syndromes, which continue to be a multifaceted challenge for patients and physicians.

RECENT FINDINGS

Newer generation pharmaceutical options are now available, such as brivaracetam, rufinamide, lacosamide, perampanel, and cannabidiol. Less restrictive dietary options appear to be nearly as effective as classic ketogenic diet for amelioration of seizures. The latest implantable devices include responsive neurostimulation and deep brain stimulation. Corpus callosotomy is an effective treatment for some seizure types, and newer and less invasive approaches are being explored. Resective surgical options have demonstrated success in carefully selected patients despite generalized electrographic findings on electroencephalogram. The current literature reflects a widening range of clinical experience with newer anticonvulsant medications including cannabinoids, dietary therapies, surgical approaches, and neurostimulation devices for patients with intractable generalized epilepsy.