Lennox-Gastaut syndrome in adulthood: Long-term clinical follow-up of 38 patients and analysis of their recorded seizures

Refining management strategies for Lennox-Gastaut syndrome: Updated algorithms and practical approaches

Lennox-Gastaut syndrome (LGS) is a severe developmental and epileptic encephalopathy (DEE) characterized by multiple types of drug-resistant seizures (which must include tonic seizures) with classical onset before 8 years (although some cases with later onset have also been described), abnormal electroencephalographic features, and cognitive and behavioral impairments. Management and treatment of LGS are challenging, due to associated comorbidities and the treatment resistance of seizures. A panel of five epileptologists reconvened to provide updated guidance and treatment algorithms for LGS, incorporating recent advancements in antiseizure medications (ASMs) and understanding of DEEs. The resulting consensus document is based on current evidence from clinical trials and clinical practice and the panel's expert opinion, focusing on new ASMs with novel mechanisms of action, such as highly purified cannabidiol and fenfluramine. For a patient presenting with newly diagnosed LGS or suspected LGS, the recommended first-line treatment continues to be valproate. If this is ineffective as monotherapy, adjunctive therapy with, firstly, lamotrigine and secondly, rufinamide, is recommended. If seizure control remains suboptimal, subsequent adjunctive ASM treatment options include (alphabetically) cannabidiol, clobazam, felbamate, fenfluramine, and topiramate, although evidence for these is more limited. Whenever possible, no more than two ASMs should be used together. Nonpharmacological treatment approaches should be used in conjunction with ASM therapy and include ketogenic diet therapies, vagus nerve stimulation, and corpus callosotomy. Patients with LGS that has evolved from another type of epilepsy who are not already being treated with valproate should be transitioned to valproate and then managed using the same algorithm as for newly diagnosed LGS. Older patients with established LGS should be reviewed at least annually by a suitably experienced neurologist. The revised guidance aims to improve seizure control and quality of life for patients with LGS through personalized, evidence-based treatment strategies while addressing the challenges of accurate diagnosis and management in a rapidly evolving therapeutic landscape. PLAIN LANGUAGE SUMMARY: Lennox-Gastaut syndrome (LGS) is a severe type of epilepsy that usually starts in childhood but continues into adulthood. It is characterized by a variety of different types of seizures (abnormal electrical activity in the brain), which are difficult to treat and often cause people with the condition to fall and injure themselves. Most people with LGS have learning difficulties and need a lot of support, often in residential care. The authors are experts in treating people with LGS and this article provides up-to-date guidance and advice on how best to care for those with the condition.

Long-term outcomes and adaptive behavior in adult patients with Lennox-Gastaut syndrome

OBJECTIVE

Lennox-Gastaut syndrome (LGS) is a severe form of epilepsy characterized by difficult-to-control seizures and cognitive dysfunction. Previous studies mainly focused on pediatric populations, and little is known about the long-term cognitive outcome in adult patients with LGS. The objective of this study was to investigate the long-term functional and adaptive behavior in adult patients with LGS.

METHODS

This cross-sectional study enrolled adult patients diagnosed with LGS according to the recently published International League Against Epilepsy (ILAE) diagnostic criteria. The adaptive behavior of participants was assessed using the Vineland Adaptive Behavior Scales, Survey Interview, Second Edition (VABS-II). Demographic, clinical, electroencephalography (EEG), and antiseizure medication (ASM) data were also collected at different timepoints, to investigate their association with VABS-II scores.

RESULTS

The study included 38 adult patients with LGS. A low score on the Adaptive Behavior Composite Scale was found in all patients. When considering single VABS-II domains, particularly low scores were found in daily living skills and socialization, whereas slightly higher performances were observed in communication. An earlier age at LGS diagnosis was identified as the most significant predictor of worse adaptive outcomes in adult life. At the time of study evaluation, high seizure frequency, higher EEG background slowing, and multifocal EEG epileptiform abnormalities were significantly associated with lower VABS-II raw scores. Furthermore, in an exploratory correlation analysis with ASM regimen at the study visit, treatment with cannabidiol was associated with higher adaptive behavior scores, whereas benzodiazepine intake correlated with lower scores.

SIGNIFICANCE

This study provides relevant insights into the long-term challenges faced by adults with Lennox-Gastaut syndrome (LGS), highlighting significant impairments in adaptive behavior as well as the associated clinical and electroencephalography features. Additionally, this study provides a more specific neuropsychological profile in adults with LGS and underscores the importance of comprehensive care approaches that go beyond seizure control in this population.

PLAIN LANGUAGE SUMMARY

This study examined adults with Lennox-Gastaut syndrome (LGS), a severe type of epilepsy, to understand their long-term abilities to perform daily tasks and adapt socially. We found that these adults have significant difficulties with daily living and social skills, although not all areas were equally affected. They performed somewhat better in communication, particularly in understanding others (receptive communication). Importantly, the younger the age at which LGS was diagnosed, the worse their outcomes were as adults. This study highlights the need for research and treatment approaches that focus not only on controlling seizures but also on improving daily life skills.

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.

The landscape of drug resistant absence seizures in adolescents and adults: Pathophysiology, electroclinical spectrum and treatment options

The persistence of typical absence seizures (AS) in adolescence and adulthood may reduce the quality of life of patients with genetic generalized epilepsies (GGEs). The prevalence of drug resistant AS is probably underestimated in this patient population, and treatment options are relatively scarce. Similarly, atypical absence seizures in developmental and epileptic encephalopathies (DEEs) may be unrecognized, and often persist into adulthood despite improvement of more severe seizures. These two seemingly distant conditions, represented by typical AS in GGE and atypical AS in DEE, share at least partially overlapping pathophysiological and genetic mechanisms, which may be the target of drug and neurostimulation therapies. In addition, some patients with drug-resistant typical AS may present electroclinical features that lie in between the two extremes represented by these generalized forms of epilepsy.

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?

Importance of targeted next-generation sequencing in pediatric patients with developmental epileptic encephalopathy

OBJECTIVE

Childhood epilepsy is a common neurological disorder with a prevalence of 300-600 cases per 100,000 people. It is associated with refractory epilepsies, global developmental delay, and epileptic encephalopathies, causing epileptic syndromes characterized by cognitive and behavioral disorders.

METHODS

In this retrospective cohort study, patients with refractory epilepsy and global developmental delay, defined as epileptic encephalopathy, who applied to the Aydın 7Maternity and Children's Hospital Genetic Diagnosis Center and were followed in the pediatric neurology clinic of our hospital, between July 2018 and July 2021, were included.

RESULTS

Targeted next-generation sequencing molecular genetics results were reviewed, and 3 ALDH7A1, 1 AARS, 3 CACNA1A, 1 CTNNB1, 1 DCX, 2 DBH, 2 DOCK7, 1 FOLR1, 2 GABRB3, 2 GCH1, 1 VGRIN2B, 1 GUF1, 3 KCNQ2, 2 KCNT1, 1 NECAP1, 1 PCDH19, 1 PNPO, 1 SCN8A, 1 SCN9A, 4 SCN1A, 2 SLC25A22, 1 SLC2A1, 2 SPTAN1, 2 SZT2, 4 TBC1D24, 2 TH, and 1 PCDH19 (X chromosome) mutations were detected in three of the patients using the next-generation sequencing method.

CONCLUSION

Although the development of gene panels aids in diagnosis, there are still unidentified disorders in this illness category, which is highly variable in genotype and phenotype. Understanding the genetic etiology is vital for genetic counseling and, maybe, the future development of remedies for the etiology.

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.

International League Against Epilepsy classification and definition of epilepsy syndromes with onset in childhood: Position paper by the ILAE Task Force on Nosology and Definitions

The 2017 International League Against Epilepsy classification has defined a three-tier system with epilepsy syndrome identification at the third level. Although a syndrome cannot be determined in all children with epilepsy, identification of a specific syndrome provides guidance on management and prognosis. In this paper, we describe the childhood onset epilepsy syndromes, most of which have both mandatory seizure type(s) and interictal electroencephalographic (EEG) features. Based on the 2017 Classification of Seizures and Epilepsies, some syndrome names have been updated using terms directly describing the seizure semiology. Epilepsy syndromes beginning in childhood have been divided into three categories: (1) self-limited focal epilepsies, comprising four syndromes: self-limited epilepsy with centrotemporal spikes, self-limited epilepsy with autonomic seizures, childhood occipital visual epilepsy, and photosensitive occipital lobe epilepsy; (2) generalized epilepsies, comprising three syndromes: childhood absence epilepsy, epilepsy with myoclonic absence, and epilepsy with eyelid myoclonia; and (3) developmental and/or epileptic encephalopathies, comprising five syndromes: epilepsy with myoclonic-atonic seizures, Lennox-Gastaut syndrome, developmental and/or epileptic encephalopathy with spike-and-wave activation in sleep, hemiconvulsion-hemiplegia-epilepsy syndrome, and febrile infection-related epilepsy syndrome. We define each, highlighting the mandatory seizure(s), EEG features, phenotypic variations, and findings from key investigations.

Long-term outcome of developmental and epileptic encephalopathies

Developmental and epileptic encephalopathies are conditions where there is developmental impairment related to both the underlying etiology independent of epileptiform activity and the epileptic encephalopathy. Usually they have multiple etiologies. Therefore, long-term outcome is related to both etiology-related factors and epilepsy-related factors-age at onset of epilepsy, type(s) of seizure(s), type of electroencephalographic abnormalities, duration of the epileptic disorder. This paper focuses on long-term outcome of six developmental and epileptic encephalopathies with onset from the neonatal period to childhood: early epileptic encephalopathy with suppression bursts, West syndrome, Dravet syndrome, Lennox-Gastaut syndrome, epilepsy with myoclonic atonic seizures and epileptic encephalopathy with continuous spike and waves during slow-wave sleep including Landau-Kleffner syndrome. For each syndrome, definition, main etiologies if multiple, and long-term outcome are discussed.

Long-term medical and social outcomes of patients with Lennox-Gastaut syndrome

OBJECTIVE

The aim of the current study was to investigate the long-term outcome in a large cohort of patients with Lennox-Gastaut syndrome (LGS).

METHODS

This was a longitudinal study (a retrospective database review with a telephone follow-up interview). All patients 18 years of age and older, with a diagnosis of LGS were studied at the outpatient epilepsy clinic at Shiraz University of Medical Sciences, Shiraz, Iran, from 2008 until 2020. The inclusion criteria were: multiple seizure types, characteristic electroencephalographic patterns [either bursts of slow spike-waves or generalized paroxysmal fast activity], with or without intellectual disability. Being lost on follow-up was the only exclusion criterion.

RESULTS

78 patients fulfilled the inclusion criteria. All the patients were followed for one to 12 years (9.3 ± 2.8 years). In the last follow-up (call), 14 patients (17.9%) were seizure-free for at least 12 months. Tonic seizure at diagnosis was associated with a poor seizure outcome (not seizure-free) (p = 0.045). Four patients (5.1%) reported having high school degree (diploma), four patients (5.1%) were married, and one person (1.3%) reported driving a motor vehicle; none of the patients were employed.

CONCLUSION

A minority of patients with LGS (almost one in six patients) may enjoy a seizure-free state in their adulthood. However, very few of them could enjoy a healthy social life. While intellectual dysfunction may not be evident at the onset of the disease, cognitive impairment usually becomes apparent over time, and almost all patients would suffer from poor social outcomes in their adulthood.

Cluster analysis of a large dataset of patients with Lennox-Gastaut syndrome

OBJECTIVES

We applied the Two-Step cluster analysis on a large cohort of patients with Lennox-Gastaut syndrome (LGS). We hypothesized that there are distinct clusters of patients with LGS based on their clinical characteristics. We also studied whether the seizure outcome differs between these patient clusters.

METHODS

This was a longitudinal study of a prospectively developed database. All patients with a diagnosis of LGS were studied at the outpatient epilepsy clinic at Shiraz University of Medical Sciences, Shiraz, Iran, from 2008 until 2020. The Two-Step cluster analysis (Schwarz's Bayesian Criterion: BIC) was applied to the whole dataset considering the demographic data, seizure types, and EEG data. In the next step, the seizure outcome was compared between the clusters of patients.

RESULTS

Two hundred and fifty-eight patients were studied. The Two-Step cluster analysis showed that there were three clusters of homogeneous subgroups of patients with LGS, with a fair silhouette measure of cohesion and separation. The seizure outcomes were significantly different between the clusters. In cluster 1, three out of 35 patients (8.6%) were seizure-free; in cluster 2, 13 out of 34 patients (38.2%) were seizure-free; and in cluster 3, nine out of 49 patients (18.4%) were seizure-free (p = 0.009; df: 2).

CONCLUSION

The Two-Step cluster analysis could identify three distinct clusters of patients with LGS; these data are helpful in providing appropriate prognosis and counselling for patients and their care-givers. Future studies should also investigate the effects of etiology in cluster analysis of patients with LGS.

The Curious Case of Lennox-Gastaut Syndrome: Treatment-Resistant Seizures in a Patient With Autism Spectrum Disease With Lennox-Gastaut Syndrome

Lennox-Gastaut syndrome (LGS) is a childhood epilepsy disorder seen between the ages of one to eight years with the electroencephalogram (EEG) changes showing slow spiked-wave complex bursts or paroxysms of generalized fast activity and intellectual disability and often needing multiple lines of treatment. Autism spectrum disease (ASD) is rare but catastrophic comorbidity seen in a patient with LGS. We report an eight-year-old boy presenting to the emergency department with seizures and mental retardation. His first seizure was at the age of five months but was symptomatically treated without any specific diagnosis. On further investigation, the patient was diagnosed with LGS with concomitant ASD. The patient has successfully been treated for his treatment-resistant seizures and is now on regular follow-ups. This article aims to highlight this rare combination of LGS along with ASD and understand the disease course.

Prevalence, healthcare resource utilization and mortality of Lennox-Gastaut syndrome: retrospective linkage cohort study

PURPOSE

To retrospectively investigate the prevalence, demography, antiseizure medication (ASM) usage, healthcare resource utilization (HCRU), and mortality of patients with Lennox-Gastaut syndrome (LGS) in primary and secondary care in the UK.

METHODS

Patients with confirmed LGS were anonymously identified from the UK Clinical Practice Research Datalink (CPRD) GOLD database (01/01/1987-31/1b0/2018) using the LGS Read Code (F250500). Probable LGS was identified using the International Classification of Diseases-10/Read Code for epilepsy (Hospital Episode Statistics [HES]/CPRD) plus rufinamide prescription. Period prevalence was calculated based on patients enrolled in CPRD GOLD and alive in 2017. CPRD data were linked to HES to calculate HCRU, and to the Office for National Statistics mortality registry.

RESULTS

Period prevalence of LGS was 0.578/10,000 (n = 180), with 74 and 106 patients identified with confirmed (0.289/10,000) and probable LGS (0.420/10,000). Mean (max) ASM usage was ~1 (3) per year. In confirmed LGS, valproate (72%), lamotrigine (69%), and clobazam (66%) were the most commonly prescribed ASMs. HCRU (per patient-year) was similar in confirmed and probable LGS and mostly consisted of primary care general practitioner consultations (4-6), outpatient visits (5-10), inpatient admissions (1-4), and A&E visits (1). During the follow-up period, 18 patients died with crude mortality rates of 6.12 (confirmed LGS) and 4.17 (probable LGS) deaths per 1000 person-years.

CONCLUSION

Prevalence of LGS appears low in the UK. The similarly high HCRU and mortality rates in confirmed and probable LGS support the validity and specificity of the probable LGS algorithm and high burden of LGS.

Anti-seizure medications for Lennox-Gastaut syndrome

BACKGROUND

Lennox-Gastaut syndrome (LGS) is an age-specific epilepsy syndrome characterised by multiple seizure types, including drop seizures. LGS has a characteristic electroencephalogram, an onset before age eight years and an association with drug resistance. This is an updated version of the Cochrane Review published in 2013.

OBJECTIVES

To assess the efficacy and tolerability of anti-seizure medications (ASMs) for LGS.

SEARCH METHODS

We searched the Cochrane Register of Studies (CRS Web) and MEDLINE (Ovid, 1946 to 28 February 2020) on 2 March 2020. CRS Web includes randomised controlled trials (RCTs) or quasi-RCTs from the Cochrane Central Register of Controlled Trials (CENTRAL); the Specialised Registers of Cochrane Review Groups, including Cochrane Epilepsy; PubMed; Embase; ClinicalTrials.gov; and the World Health Organization's International Clinical Trials Registry Platform (ICTRP). We imposed no language restrictions. We contacted pharmaceutical companies and colleagues in the field to seek any unpublished or ongoing studies.

SELECTION CRITERIA

We considered RCTs, including cross-over trials, of ASMs for LGS in children and adults. We included studies of ASMs used as either monotherapy or as an add-on (adjunctive) therapy. We excluded studies comparing different doses of the same ASM.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures, including independent, dual assessment for risk of bias and application of the GRADE approach to rate the evidence certainty for outcomes.

MAIN RESULTS

We found no trials of ASM monotherapy. The review included 11 trials (1277 participants; approximately 11 weeks to 112 weeks follow-up after randomisation) using add-on ASMs for LGS in children, adolescents and adults. Two studies compared add-on cannabidiol (two doses) with add-on placebo in children and adolescents only. Neither study reported overall seizure cessation or reduction. We found high-certainty evidence that 72 more people per 1000 (confidence interval (CI) 4 more to 351 more) had adverse events (AE) leading to study discontinuation with add-on cannabidiol, compared to add-on placebo (two studies; 396 participants; risk ratio (RR) 4.90, 95% CI 1.21 to 19.87). One study compared add-on cinromide with add-on placebo in children and adolescents only. We found very low-certainty evidence that 35 more people per 1000 (CI 123 fewer to 434 more) had 50% or greater average reduction of overall seizures with add-on cinromide compared to add-on placebo (one study; 56 participants; RR 1.15, 95% CI 0.47 to 2.86). This study did not report participants with AE leading to study discontinuation. One study compared add-on clobazam (three doses) with add-on placebo. This study did not report overall seizure cessation or reduction. We found high-certainty evidence that 106 more people per 1000 (CI 0 more to 538 more) had AE leading to study discontinuation with add-on clobazam compared to add-on placebo (one study; 238 participants; RR 4.12, 95% CI 1.01 to 16.87). One study compared add-on felbamate with add-on placebo. No cases of seizure cessation occurred in either regimen during the treatment phase (one study; 73 participants; low-certainty evidence). There was low-certainty evidence that 53 more people per 1000 (CI 19 fewer to 716 more) with add-on felbamate were seizure-free during an EEG recording at the end of the treatment phase, compared to add-on placebo (RR 2.92, 95% CI 0.32 to 26.77). The study did not report overall seizure reduction. We found low-certainty evidence that one fewer person per 1000 (CI 26 fewer to 388 more) with add-on felbamate had AE leading to study discontinuation compared to add-on placebo (one study, 73 participants; RR 0.97, 95% CI 0.06 to 14.97). Two studies compared add-on lamotrigine with add-on placebo. Neither study reported overall seizure cessation. We found high-certainty evidence that 176 more people per 1000 (CI 30 more to 434 more) had ≥ 50% average seizure reduction with add-on lamotrigine compared to add-on placebo (one study; 167 participants; RR 2.12, 95% CI 1.19 to 3.76). We found low-certainty evidence that 40 fewer people per 1000 (CI 68 fewer to 64 more) had AE leading to study-discontinuation with add-on lamotrigine compared to add-on placebo (one study; 169 participants; RR 0.49, 95% CI 0.13 to 1.82). Two studies compared add-on rufinamide with add-on placebo. Neither study reported seizure cessation. We found high-certainty evidence that 202 more people per 1000 (CI 34 to 567 more) had ≥ 50% average seizure reduction (one study; 138 participants; RR 2.84, 95% CI 1.31 to 6.18). We found low-certainty evidence that 105 more people per 1000 (CI 17 fewer to 967 more) had AE leading to study discontinuation with add-on rufinamide compared to add-on placebo (one study; 59 participants; RR 4.14, 95% CI 0.49 to 34.86). One study compared add-on rufinamide with another add-on ASM. This study did not report overall seizure cessation or reduction. We found low-certainty evidence that three fewer people per 1000 (CI 75 fewer to 715 more) had AE leading to study discontinuation with add-on rufinamide compared to another add-on ASM (one study; 37 participants; RR 0.96, 95% CI 0.10 to 9.57). One study compared add-on topiramate with add-on placebo. This study did not report overall seizure cessation. We found low-certainty evidence for ≥ 75% average seizure reduction with add-on topiramate (one study; 98 participants; Peto odds ratio (Peto OR) 8.22, 99% CI 0.60 to 112.62) and little or no difference to AE leading to study discontinuation compared to add-on placebo; no participants experienced AE leading to study discontinuation (one study; 98 participants; low-certainty evidence).

AUTHORS' CONCLUSIONS

RCTs of monotherapy and head-to-head comparison of add-on ASMs are currently lacking. However, we found high-certainty evidence for overall seizure reduction with add-on lamotrigine and rufinamide, with low-certainty evidence for AE leading to study discontinuation compared with add-on placebo or another add-on ASM. The evidence for other add-on ASMs for overall seizure cessation or reduction was low to very low with high- to low-certainty evidence for AE leading to study discontinuation. Future research should consider outcome reporting of overall seizure reduction (applying automated seizure detection devices), impact on development, cognition and behaviour; future research should also investigate age-specific efficacy of ASMs and target underlying aetiologies.

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.

Expert opinion: Proposed diagnostic and treatment algorithms for Lennox-Gastaut syndrome in adult patients

Lennox-Gastaut syndrome (LGS) is a severe developmental epileptic encephalopathy diagnosed in childhood that persists through adolescence and into adulthood. While the characteristics of LGS in pediatric patients are well defined, including "drop attacks", interictal slow spike and wave electroencephalogram (EEG) activity, and intellectual disability, these features can evolve over time, and different EEG activities may be present in adult patients with LGS. This may result in missed diagnoses in these patients and subsequent challenges for the adequate treatment of their seizures. Based on discussions held during the LGS Transition of Care advisory board meeting and thereafter, we developed proposed diagnostic and treatment algorithms for LGS in adult patients. We highlight readily available assessments to facilitate diagnosis of LGS, based on past medical history and physical examination. The LGS diagnostic algorithm recommends that clinicians consider the occurrence of wider seizure types and abnormal EEG activities to be potentially indicative of LGS. Seizure types may include atypical absence seizures, myoclonic seizures, focal seizures, and tonic-clonic seizures, and EEG may demonstrate background slowing, focal or multifocal epileptiform discharges, and diffuse fast rhythms during sleep, among other activities. Extended EEG during sleep and video-EEG should be used in equivocal cases. Treatment of LGS in adult patients should incorporate both antiseizure drug (ASD) therapy and nonpharmacologic approaches. Frequent reassessment of patients is considered a central aspect. ASDs were categorized based on order of preference for use in the treatment of LGS; Tier 1 comprises recommended first-line ASDs, and includes valproate, clobazam, lamotrigine, rufinamide, topiramate, and cannabidiol. Other treatment options include diet, neurostimulation, and surgical approaches. Developments with the potential to improve diagnosis in the future include genetic screening, while novel ASDs and advances in neurostimulation techniques may provide valuable treatment options. These algorithms should be frequently revisited to incorporate improved techniques and therapies.

GABAA receptor β3 subunit mutation D120N causes Lennox-Gastaut syndrome in knock-in mice

The Lennox-Gastaut syndrome is a devastating early-onset epileptic encephalopathy, associated with severe behavioural abnormalities. Its pathophysiology, however, is largely unknown. A de novo mutation (c.G358A, p.D120N) in the human GABA type-A receptor β3 subunit gene (GABRB3) has been identified in a patient with Lennox-Gastaut syndrome. To determine whether the mutation causes Lennox-Gastaut syndrome in vivo in mice and to elucidate its mechanistic effects, we generated the heterozygous Gabrb3+/D120N knock-in mouse and found that it had frequent spontaneous atypical absence seizures, as well as less frequent tonic, myoclonic, atonic and generalized tonic-clonic seizures. Each of these seizure types had a unique and characteristic ictal EEG. In addition, knock-in mice displayed abnormal behaviours seen in patients with Lennox-Gastaut syndrome including impaired learning and memory, hyperactivity, impaired social interactions and increased anxiety. This Gabrb3 mutation did not alter GABA type-A receptor trafficking or expression in knock-in mice. However, cortical neurons in thalamocortical slices from knock-in mice had reduced miniature inhibitory post-synaptic current amplitude and prolonged spontaneous thalamocortical oscillations. Thus, the Gabrb3+/D120N knock-in mouse recapitulated human Lennox-Gastaut syndrome seizure types and behavioural abnormalities and was caused by impaired inhibitory GABAergic signalling in the thalamocortical loop. In addition, treatment with antiepileptic drugs and cannabinoids ameliorated atypical absence seizures in knock-in mice. This congenic knock-in mouse demonstrates that a single-point mutation in a single gene can cause development of multiple types of seizures and multiple behavioural abnormalities. The knock-in mouse will be useful for further investigation of the mechanisms of Lennox-Gastaut syndrome development and for the development of new antiepileptic drugs and treatments.

Lennox-Gastaut Syndrome: In a Nutshell

Lennox-Gastaut syndrome is one of the rare childhood-onset epileptic encephalopathies, characterized by multiple type seizure disorder, the typical pattern on electroencephalogram and intellectual disability. Tonic-type seizures are most commonly seen in these patients. Behavioral disturbances and cognitive decline are gradual-onset and last long after the first episode of epileptiform activity. In most cases, there is some identifiable cause that has led to the clinical presentation of the patient. Various pharmacological and surgical procedures have been proposed for the treatment of Lennox-Gastaut syndrome and many more to come in the very near future to overcome the drug resistance and to avoid the patient forming a life-long dependency.