Development and validation of a predictive model of drug-resistant genetic generalized epilepsy

A generalized seizure type: Myoclonic-to-tonic seizure

BACKGROUND AND PURPOSE

To test the hypothesis that myoclonic seizures can evolve to tonic seizures, we documented the electroclinical features of this under-recognized seizure type.

METHODS

We observed a distinct seizure pattern starting with myoclonus without returning to an interictal state, which subsequently evolved into generalized tonic seizures. The detailed symptomatic and electroencephalographic characteristics of this seizure were extracted, and the clinical manifestations, drug curative responses in patients with this seizure were reviewed and analyzed.

RESULTS

The onset of all seizures was characterized by a preceding period of myoclonus and bursts of generalized spike or poly-spike slow wave discharges with high amplitude. This was closely followed by the occurrence of tonic seizures, which were distinguished by bursts of generalized fast activity at 10 Hz or higher frequency. This under-recognized seizure type has been designated as myoclonic-to-tonic (MT) seizure. The number of patients identified with MT seizures in this study was 34. The prevalence rate of MT seizures was found to be higher in males. While MT seizures typically included a tonic component, it should be noted that some patients experiencing this seizure type never presented with isolated tonic seizures. Generalized Epilepsy not further defined (GE) accounted for approximately one-third of the diagnosed cases, followed by Lennox-Gastaut syndrome and Epilepsy with Myoclonic-Atonic seizures. In comparison to other types of epilepsy, GE with MT seizures demonstrated a more favorable prognosis.

CONCLUSIONS

The classification of myoclonic-to-tonic seizure represents a novel approach in comprehending the ictogenesis of generalized seizures and can provide valuable assistance to clinicians in epilepsy diagnosis.

Oligoepilepsy and lifelong seizure susceptibility in epilepsy with generalized tonic-clonic seizures alone: Experience at an adult tertiary center

OBJECTIVE

Epilepsy with generalized tonic-clonic seizures alone (GTCA) is the least studied syndrome within the idiopathic generalized epilepsy (IGE) spectrum. We characterize a large cohort of adult patients with GTCA to understand natural history and drug responsiveness.

METHODS

In this retrospective single-center study using our epilepsy electronic record, we evaluated clinical characteristics, seizure outcomes, anti-seizure medication (ASM) response including seizure recurrence after ASM withdrawal, and sex differences in a cohort of GTCA patients aged ≥17 years.

RESULTS

Within a cohort of 434 IGE patients, 87 patients (20 %) with GTCA were included. The mean age was 34.9 years (range 17-73 years). Forty-six patients (52.8 %) were females. Seventy-two patients (82.8 %) were seizure-free and 15 (17.2 %) had active epilepsy over the previous 12 months. Thirty-four patients (39.1 %) had ≤5 lifetime seizures, aligning with a prior definition of 'oligoepilepsy'. Sixty-five patients (74.7 %) were treated with monotherapy, 19 (21.8 %) were treated with polytherapy, and three were not taking any ASM. Levetiracetam (37.9 %) was the most commonly prescribed ASM, followed by lamotrigine (32.1 %) and valproate (31 %). Seventeen patients (19.5 %) attempted to withdraw their ASM. The rate of seizure recurrence after ASM withdrawal was 88.2 % (15/17), including two patients who relapsed more than 20 years after ASM discontinuation. Females had more seizures in their lifetime and had trialed more ASM compared to males.

SIGNIFICANCE

GTCA has a relatively good prognosis, with most patients becoming seizure-free on monotherapy. The high rate of seizure recurrence after ASM withdrawal supports lifetime seizure susceptibility. We found potential sex differences in seizure outcomes and ASM response, although further research is needed to validate this finding.

Predictors of Seizure Recurrence in Women With Idiopathic Generalized Epilepsy Who Switch From Valproate to Another Medication

BACKGROUND AND OBJECTIVES

To investigate the predictors of seizure recurrence in women of childbearing age with idiopathic generalized epilepsy (IGE) who switched from valproate (VPA) to alternative antiseizure medications (ASMs) and compare the effectiveness of levetiracetam (LEV) and lamotrigine (LTG) as VPA alternatives after switch.

METHODS

This multicenter retrospective study included women of childbearing age diagnosed with IGE from 16 epilepsy centers. Study outcomes included worsening or recurrence of generalized tonic-clonic seizure (GTCS) at 12 months and 24 months after the switch from VPA to an alternative ASM. The comparative effectiveness of LEV and LTG as alternative ASM following VPA discontinuation was assessed through inverse probability treatment-weighted (IPTW) Cox regression analysis.

RESULTS

We included 426 women with IGE, with a median (interquartile range) age at VPA switch of 24 (19-30) years and a median VPA dosage of 750 (500-1,000) mg/d. The most common reason for VPA switch was teratogenicity concern in 249 women (58.6%), and the most common ASM used in place of VPA was LEV in 197 (46.2%) cases, followed by LTG in 140 (32.9%). GTCS worsening/recurrence occurred in 105 (24.6%) and 139 (32.6%) women at 12 and 24 months, respectively. Catamenial worsening of seizures, higher VPA dosage during switch, multiple seizure types, and shorter duration of GTCS freedom before switch were independent predictors of GTCS recurrence or worsening at 12 months according to mixed multivariable logistic regression analysis. After internal-external validation through 16 independent cohorts, the model showed an area under the curve of 0.71 (95% CI 0.64-0.77). In the subgroup of 337 women who switched to LEV or LTG, IPTW Cox regression analysis showed that LEV was associated with a reduced risk of GTCS worsening or recurrence compared with LTG (adjusted hazard ratio 0.59, 95% CI 0.40-0.87, p = 0.008) during the 24-month follow-up.

DISCUSSION

Our findings can have practical implications for optimizing counselling and treatment choices in women of childbearing age with IGE and may help clinicians in making informed treatment decisions in this special population of patients.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that for women with IGE switching from VPA, LEV was associated with a reduced risk of GTCS worsening or recurrence compared with LTG.

Drug-resistant juvenile myoclonic epilepsy: A literature review

The ILAE's Task Force on Nosology and Definitions revised in 2022 its definition of juvenile myoclonic epilepsy (JME), the most common idiopathic generalized epilepsy disorder, but this definition may well change again in the future. Although good drug response could almost be a diagnostic criterion for JME, drug resistance (DR) is observed in up to a third of patients. It is important to distinguish this from pseudoresistance, which is often linked to psychosocial problems or psychiatric comorbidities. After summarizing these aspects and the various definitions applied to JME, the present review lists the risk factors for DR-JME that have been identified in numerous studies and meta-analyses. The factors most often cited are absence seizures, young age at onset, and catamenial seizures. By contrast, photosensitivity seems to favor good treatment response, at least in female patients. Current hypotheses on DR mechanisms in JME are based on studies of either simple (e.g., cortical excitability) or more complex (e.g., anatomical and functional connectivity) neurophysiological markers, bearing in mind that JME is regarded as a neural network disease. This research has revealed correlations between the intensity of some markers and DR, and above all shed light on the role of these markers in associated neurocognitive and neuropsychiatric disorders in both patients and their siblings. Studies of neurotransmission have mainly pointed to impaired GABAergic inhibition. Genetic studies have generally been inconclusive. Increasing restrictions have been placed on the use of valproate, the standard antiseizure medication for this syndrome, owing to its teratogenic and developmental risks. Levetiracetam and lamotrigine are prescribed as alternatives, as is vagal nerve stimulation, and there are several other promising antiseizure drugs and neuromodulation methods. The development of better alternative treatments is continuing to take place alongside advances in our knowledge of JME, as we still have much to learn and understand.

Epilepsy with generalized tonic-clonic seizures alone: Electroclinical features and prognostic patterns

OBJECTIVE

Epilepsy with generalized tonic-clonic seizures alone (GTCA) is a common but poorly characterized idiopathic generalized epilepsy (IGE) syndrome. Hence, we investigated electroclinical features, seizure outcome, and antiseizure medication (ASM) withdrawal in a large cohort of GTCA patients.

METHODS

In this multicenter retrospective study, GTCA patients defined according to the diagnostic criteria of the International League Against Epilepsy (2022) were included. We investigated prognostic patterns, drug resistance at the last visit, and ASM withdrawal, along with their prognostic factors.

RESULTS

We included 247 patients with a median (interquartile range [IQR]) age at onset of 17 years (13-22) and a median follow-up duration of 10 years (IQR = 5-20). Drug resistance at the last visit was observed in 40 (16.3%) patients, whereas the median latency to achieve 2-year remission was 24 months (IQR = 24-46.5) with a median number of 1 (IQR = 1-2) ASM. During the long-term follow-up (i.e., 202 patients followed ≥5-years after the first ASM trial), 69 (34.3%) patients displayed an early remission pattern and 36 (17.9%) patients displayed a late remission pattern, whereas 16 (8%) and 73 (36.3%) individuals had no-remission and relapsing-remitting patterns, respectively. Catamenial seizures and morning predominance of generalized tonic-clonic seizures (GTCS) independently predicted drug resistance at the last visit according to multivariable logistic regression. Treatment withdrawal was attempted in 63 (25.5%) patients, with 59 (93.7%) of them having at least a 12-month follow-up after ASM discontinuation. At the last visit, 49 (83%) of those patients had experienced GTCS recurrence. A longer duration of seizure freedom was the only factor predicting a higher chance of successful ASM withdrawal according to multivariable Cox regression.

SIGNIFICANCE

GTCA could be considered a relatively easily manageable IGE syndrome, with a low rate of drug resistance and a high prevalence of early response to treatment. Nevertheless, a considerable proportion of patients experience relapsing patterns of seizure control, highlighting the need for appropriate counseling and lifestyle recommendations.

Revisiting the concept of drug-resistant epilepsy: A TASK1 report of the ILAE/AES Joint Translational Task Force

Despite progress in the development of anti-seizure medications (ASMs), one third of people with epilepsy have drug-resistant epilepsy (DRE). The working definition of DRE, proposed by the International League Against Epilepsy (ILAE) in 2010, helped identify individuals who might benefit from presurgical evaluation early on. As the incidence of DRE remains high, the TASK1 workgroup on DRE of the ILAE/American Epilepsy Society (AES) Joint Translational Task Force discussed the heterogeneity and complexity of its presentation and mechanisms, the confounders in drawing mechanistic insights when testing treatment responses, and barriers in modeling DRE across the lifespan and translating across species. We propose that it is necessary to revisit the current definition of DRE, in order to transform the preclinical and clinical research of mechanisms and biomarkers, to identify novel, effective, precise, pharmacologic treatments, allowing for earlier recognition of drug resistance and individualized therapies.

Efficacy of a pre-specified timeline-based treatment protocol in children with acute repetitive seizures or seizure clusters

Objectives

Acute repetitive seizures (ARSs) are one of the few commonly encountered neurological emergencies in children. There is a need for an appropriate timeline-based treatment protocol, which will be shown to be safe and efficacious in a clinical study.

Materials and Methods

This was a retrospective chart review to determine the efficacy of a pre-specified treatment protocol for the management of ARSs in children aged 1-18 years. The treatment protocol was specifically applied in children with a diagnosis of epilepsy and not critically ill, who met the criteria for ARSs, with the exemption of new onset of ARSs. The first tier of treatment protocol focused on intravenous lorazepam, optimization of dose of existing anti-seizure medications (ASMs), and control of triggers like acute febrile illness, while second-tier focused on adding one or two additional ASMs, commonly used in cases with seizure clusters or status epilepticus.

Results

We included the first 100 consecutive patients (7.6 ± 3.2 years, 63% boys). Our treatment protocol was successful in 89 patients (58 and 31 required first-tier and second-tier treatment). The absence of pre-existing drug-resistant epilepsy and the presence of acute febrile illness as a triggering factor (P = 0.02 and 0.03) were associated with the success of the first tier of the treatment protocol. Excessive sedation (n = 29), incoordination (n = 14), transient gait instability (n = 11), and excessive irritability (n = 5) were the most common adverse effects observed during the initial 1 week.

Conclusion

This pre-specified treatment protocol is safe and efficacious in controlling ARSs in cases with established epilepsy who are not critically sick. External validation from other parts of the world/centers and a more diverse epilepsy population are required before generalizing the protocol into clinical practice.

Sex and estrous cycle stage shape left-right asymmetry in chronic hippocampal seizures in mice

Lateralization of hippocampal function is indicated by varied outcomes of patients with neurological disorders that selectively affect one hemisphere of this structure, such as temporal lobe epilepsy (TLE). The intrahippocampal kainic acid (IHKA) injection model of TLE allows for targeted damage to the left or right hippocampus, enabling systematic comparison of effects of left-right asymmetry on seizure and non-seizure outcomes. Although varying non-seizure phenotypic outcomes based on injection side in dorsal hippocampus were recently evaluated in this model, differences in chronic seizure patterns in left- (IHKA-L) vs. right-injected (IHKA-R) IHKA animals have yet to be evaluated. Here, we evaluated hippocampal seizure incidence in male and female IHKA-L and IHKA-R mice. Females displayed increased electrographic seizure activity compared to males at both 2 months and 4 months post-injection (mpi). In addition, IHKA-L females showed higher seizure frequency than IHKA-R on diestrus and estrus at 2 mpi, but seizure duration and time in seizures were only higher in IHKA-L females on diestrus. These cycle stage-associated changes, however, did not persist to 4 mpi. Furthermore, this lateralized difference in seizure burden was not observed in males. These results indicate for the first time that the side of IHKA injection can shape chronic electrographic seizure burden. Overall, these results demonstrate a female-specific left-right asymmetry in hippocampal function can interact with estrous cycle stage to shape chronic seizures in mice with epilepsy, with implications for neural activity and behavior in both normal and disease states.

Drug resistance in idiopathic generalized epilepsies: Evidence and concepts

Although approximately 10%-15% of patients with idiopathic generalized epilepsy (IGE)/genetic generalized epilepsy remain drug-resistant, there is no consensus or established concept regarding the underlying mechanisms and prevalence. This review summarizes the recent data and the current hypotheses on mechanisms that may contribute to drug-resistant IGE. A literature search was conducted in PubMed and Embase for studies on mechanisms of drug resistance published since 1980. The literature shows neither consensus on the definition nor a widely accepted model to explain drug resistance in IGE or one of its subsyndromes. Large-scale genetic studies have failed to identify distinct genetic causes or affected genes involved in pharmacokinetics. We found clinical and experimental evidence in support of four hypotheses: (1) "network hypothesis"-the degree of drug resistance in IGE reflects the severity of cortical network alterations, (2) "minor focal lesion in a predisposed brain hypothesis"-minor cortical lesions are important for drug resistance, (3) "interneuron hypothesis"-impaired functioning of γ-aminobutyric acidergic interneurons contributes to drug resistance, and (4) "changes in drug kinetics"-genetically impaired kinetics of antiseizure medication (ASM) reduce the effectiveness of available ASMs. In summary, the exact definition and cause of drug resistance in IGE is unknown. However, published evidence suggests four different mechanisms that may warrant further investigation.

Individualised prediction of drug resistance and seizure recurrence after medication withdrawal in people with juvenile myoclonic epilepsy: A systematic review and individual participant data meta-analysis

Background

A third of people with juvenile myoclonic epilepsy (JME) are drug-resistant. Three-quarters have a seizure relapse when attempting to withdraw anti-seizure medication (ASM) after achieving seizure-freedom. It is currently impossible to predict who is likely to become drug-resistant and safely withdraw treatment. We aimed to identify predictors of drug resistance and seizure recurrence to allow for individualised prediction of treatment outcomes in people with JME.

Methods

We performed an individual participant data (IPD) meta-analysis based on a systematic search in EMBASE and PubMed - last updated on March 11, 2021 - including prospective and retrospective observational studies reporting on treatment outcomes of people diagnosed with JME and available seizure outcome data after a minimum one-year follow-up. We invited authors to share standardised IPD to identify predictors of drug resistance using multivariable logistic regression. We excluded pseudo-resistant individuals. A subset who attempted to withdraw ASM was included in a multivariable proportional hazards analysis on seizure recurrence after ASM withdrawal. The study was registered at the Open Science Framework (OSF; https://osf.io/b9zjc/).

Findings

Our search yielded 1641 articles; 53 were eligible, of which the authors of 24 studies agreed to collaborate by sharing IPD. Using data from 2518 people with JME, we found nine independent predictors of drug resistance: three seizure types, psychiatric comorbidities, catamenial epilepsy, epileptiform focality, ethnicity, history of CAE, family history of epilepsy, status epilepticus, and febrile seizures. Internal-external cross-validation of our multivariable model showed an area under the receiver operating characteristic curve of 0·70 (95%CI 0·68-0·72). Recurrence of seizures after ASM withdrawal (n = 368) was predicted by an earlier age at the start of withdrawal, shorter seizure-free interval and more currently used ASMs, resulting in an average internal-external cross-validation concordance-statistic of 0·70 (95%CI 0·68-0·73).

Interpretation

We were able to predict and validate clinically relevant personalised treatment outcomes for people with JME. Individualised predictions are accessible as nomograms and web-based tools.

Funding

MING fonds.

Potential clinical and biochemical markers for the prediction of drug-resistant epilepsy: A literature review

Drug resistance is a major challenge in the treatment of epilepsy. Drug-resistant epilepsy (DRE) accounts for 30% of all cases of epilepsy and is a matter of great concern because of its uncontrollability and the high burden, mortality rate, and degree of damage. At present, considerable research has focused on the development of predictors to aid in the early identification of DRE in an effort to promote prompt initiation of individualized treatment. While multiple predictors and risk factors have been identified, there are currently no standard predictors that can be used to guide the clinical management of DRE. In this review, we discuss several potential predictors of DRE and related factors that may become predictors in the future and perform evidence rating analysis to identify reliable potential predictors.

Risk Prediction Models for Early ICU Admission in Patients With Autoimmune Encephalitis: Integrating Scale-Based Assessments of the Disease Severity

Background

In patients with autoimmune encephalitis (AE), the prediction of progression to a critically ill status is challenging but essential. However, there is currently no standard prediction model that comprehensively integrates the disease severity and other clinical features. The clinical assessment scale in autoimmune encephalitis (CASE) and the modified Rankin Scale (mRS) have both been applied for evaluating the severity of AE. Here, by combining the two scales and other clinical characteristics, we aimed to investigate risk factors and construct prediction models for early critical care needs of AE patients.

Methods

Definite and probable AE patients who were admitted to the neurology department of Tongji Hospital between 2013 and 2021 were consecutively enrolled. The CASE and mRS scores were used to evaluate the overall symptom severity at the time of hospital admission. Using logistic regression analysis, we analyzed the association between the total scores of the two scales and critical illness individually and then we evaluated this association in combination with other clinical features to predict early intensive care unit (ICU) admission. Finally, we constructed four prediction models and compared their performances.

Results

Of 234 patients enrolled, forty developed critical illness and were early admitted to the ICU (within 14 days of hospitalization). Four prediction models were generated; the models were named CASE, CASE-plus (CASE + prodromal symptoms + elevated fasting blood glucose + elevated cerebrospinal fluid (CSF) white blood cell (WBC) count), mRS and mRS-plus (mRS + prodromal symptoms + abnormal EEG results + elevated fasting blood glucose + elevated CSF WBC count) and had areas under the ROC curve of 0.850, 0.897, 0.695 and 0.833, respectively. All four models had good calibrations. In general, the models containing “CASE” performed better than those including “mRS”, and the CASE-plus model demonstrated the best performance.

Conclusion

Overall, the symptom severity at hospital admission, as defined by CASE or mRS, could predict early ICU admission, especially when assessed by CASE. Adding other clinical findings, such as prodromal symptoms, an increased fasting blood glucose level and an increased CSF WBC count, could improve the predictive efficacy.

Seizure remission rates remain low in a resource-limited country, a multicentre comparison study in Malaysia

Seizure remission rates of 60% with antiseizure medications were reported in developed countries, but might be lower in resource-limited countries. The challenges in epilepsy care in resource-limited regions were highlighted 10 years ago, and still remain an ongoing issue. This study aimed to determine the seizure freedom rates in level-2 epilepsy care centres (centres with general neurologists) compared to level-3/4 centres (centres with epileptologists providing epilepsy surgery evaluation) in Malaysia. This is a retrospective study of 1,347 adult epilepsy patients from two level-2 (n = 290) and two level-3/4 epilepsy care centres (n = 1,057). The seizure remission rates were significantly lower in level-2 centres (42.5%) compared to the level 3/4 centres (61.9%, p < 0.05). Level-2 centres had significantly more patients with undetermined seizure types compared to level-3/4 centres (6.6% vs 3.1%, p < 0.05). Level-3/4 centres had significantly more patients with epilepsy of structural and genetic origins, whereas more patients in level-2 centres had unknown aetiology (46.2% vs. 34.0% in level-3/4, p < 0.05). Level-2 centres had a lower neurologist-to-patient ratio (1:97 vs. 1:50 in level-3/4 centres, p < 0.05). Level-2 centres also had fewer patients, who underwent investigations such as EEG (74.1% vs. 89.6%) and brain MRI (54.1% vs. 72.4%, p < 0.05) in comparison with level-3/4 centres. Our study emphasized the existing challenges in epilepsy care in a resource-limited country to achieve the ideal 60% seizure remission rate.

Electroclinical Features and Long-term Seizure Outcome in Patients With Eyelid Myoclonia With Absences

BACKGROUND AND OBJECTIVES

Eyelid myoclonia with absences (EMA) is a generalized epilepsy syndrome whose prognosis and clinical characteristics are still partially undefined. We investigated electroclinical endophenotypes and long-term seizure outcome in a large cohort of EMA patients.

METHODS

In this multicenter retrospective study, EMA patients with ≥5 years of follow-up were included. We investigated prognostic patterns and sustained terminal remission (STR), along with their prognostic factors. Moreover, a two-step cluster analysis was used to investigate the presence of distinct EMA endophenotypes.

RESULTS

We included 172 patients, with a median age at onset of 7 years (interquartile range (IQR) 5-10) and a median follow-up duration of 14 years (IQR 8.25-23.75). Sixty-six patients (38.4%) displayed a non-remission pattern, whereas remission and relapse patterns were encountered in 56 (32.6%) and 50 (29.1%) subjects. Early epilepsy onset, history of febrile seizures (FS) and eyelid myoclonia (EM) status epilepticus significantly predicted a non-remission pattern according to multinomial logistic regression analysis. STR was achieved by 68 (39.5%) patients with a mean latency of 14.05 years (SD ± 12.47). Early epilepsy onset, psychiatric comorbidities, and a history of FS and generalized tonic-clonic seizures (GTCS) were associated with a lower probability of achieving STR according to a Cox regression proportional hazards model. Antiseizure medication (ASM) withdrawal was attempted in 62/172 patients, and seizures relapsed in 74.2%. Cluster analysis revealed two distinct clusters with 86 patients each. Cluster 2, which we defined as "EMA-plus", was characterized by an earlier age at epilepsy onset, higher rate of intellectual disability, EM status epilepticus, generalized paroxysmal fast activity, self-induced seizures, FS, and poor ASM response, whereas Cluster 1, the "EMA-only" cluster, was characterized by a higher rate of seizure remission and more favorable neuropsychiatric outcome.

DISCUSSION

Early epilepsy onset was the most relevant prognostic factor for poor treatment response. A long latency between epilepsy onset and ASM response was observed, suggesting the impact of age-related brain changes in EMA remission. Finally, our cluster analysis showed a clear-cut distinction of EMA patients into an EMA-plus insidious subphenotype and an EMA-only benign cluster that strongly differed in terms of remission rates and cognitive outcomes.

Seizure outcome trajectories in a well-defined cohort of newly diagnosed juvenile myoclonic epilepsy patients

OBJECTIVE

To investigate the temporal course of medication response and associated prognostic factors in a cohort of juvenile myoclonic epilepsy (JME) patients over a long-term follow-up.

MATERIALS AND METHODS

Data from 113 JME patients diagnosed according to recently proposed class II criteria were retrospectively reviewed. Early sustained remission was defined as 4-year seizure remission starting within 2 years from the first antiseizure medication (ASM) intake, as opposed to delayed sustained remission. Spontaneous relapse rate (ie, not related to ASM withdrawal) was also investigated, along with factors associated with seizure relapse.

RESULTS

Four-year seizure remission was obtained by 76/113 (67.3%) subjects. Early sustained remission was achieved by 45/76 (59.2%) patients. Absence seizures were significantly associated with no-remission at multivariable multinomial logistic regression analysis. Catamenial seizures and earlier age at epilepsy onset significantly predicted delayed sustained remission. Spontaneous seizure relapse after 4-year remission occurred in 15.7% of patients with early sustained remission and in 35.5% of those with delayed sustained remission (p = 0.045). The most common concomitant factors for a spontaneous relapse were irregular lifestyle habits and pregnancy-related switch from valproate to another ASM. Patients with a history of catamenial seizures were more likely to experience a spontaneous generalized tonic-clonic seizure relapse after 4-year remission at univariable analysis.

SIGNIFICANCE

Our data support the prognostic relevance of early medication response in JME patients. Furthermore, the prognostic significance of catamenial seizures and the impact of valproate switch on seizure relapse after a prolonged remission account for the challenging therapeutic management of women with childbearing potential.

Sex-specific disease modifiers in juvenile myoclonic epilepsy

Juvenile myoclonic epilepsy (JME) is a common idiopathic generalised epilepsy with variable seizure prognosis and sex differences in disease presentation. Here, we investigate the combined epidemiology of sex, seizure types and precipitants, and their influence on prognosis in JME, through cross-sectional data collected by The Biology of Juvenile Myoclonic Epilepsy (BIOJUME) consortium. 765 individuals met strict inclusion criteria for JME (female:male, 1.8:1). 59% of females and 50% of males reported triggered seizures, and in females only, this was associated with experiencing absence seizures (OR = 2.0, p < 0.001). Absence seizures significantly predicted drug resistance in both males (OR = 3.0, p = 0.001) and females (OR = 3.0, p < 0.001) in univariate analysis. In multivariable analysis in females, catamenial seizures (OR = 14.7, p = 0.001), absence seizures (OR = 6.0, p < 0.001) and stress-precipitated seizures (OR = 5.3, p = 0.02) were associated with drug resistance, while a photoparoxysmal response predicted seizure freedom (OR = 0.47, p = 0.03). Females with both absence seizures and stress-related precipitants constitute the prognostic subgroup in JME with the highest prevalence of drug resistance (49%) compared to females with neither (15%) and males (29%), highlighting the unmet need for effective, targeted interventions for this subgroup. We propose a new prognostic stratification for JME and suggest a role for circuit-based risk of seizure control as an avenue for further investigation.

Different Prognostic Patterns in Epilepsies and Considerations About the Denotations of Atypical Patterns

Epilepsy is a dynamic and heterogeneous neurological disease, and in long-term studies on prognosis, classically 5 basic patterns (early remission, late remission, relapsing-remitting, worsening, and non-remitting) have been identified. The most frequent pattern was relapsing-remitting course, and factors such as the presence of genetic etiology, rare seizures at the beginning of epilepsy and the absence of psychiatric comorbid diseases were found to be related with this pattern as well as reaching 5 years of remission in the follow-ups. Anti-seizure drug resistance (ASD-R) and factors affecting the presence of this resistance (such as symptomatic etiology, abnormal electroencephalographic findings, having multiple seizure types together, status epilepticus and febrile seizure history) decrease the chance of remission, while idiopathic/genetic etiology, generalized epilepsy, and absence of comorbid diseases seem to be associated with achieving long-term remission. Apart from these basic course patterns, there are some patients with an "atypical prognosis" such as drug-resistant juvenile myoclonic epilepsy (JME), benign hippocampal sclerosis-related mesial temporal lobe epilepsy (HS-MTLE), and severe childhood epilepsy with centro-temporal spikes (CESTS), in which the pathophysiological mechanisms underlying these patterns have not been clarified despite the suggestions of various hypotheses. The presence of comorbid diseases such as hormonal factors (as in catamenial epilepsy), autoimmune processes, thyroid disorders and metabolic and psychiatric diseases may also cause an atypical prognostic pattern by affecting the course of the disease. In this review, our aim is to provide the clinician with an up-to-date and questioning perspective on the prognostic markers of epilepsy, by examining in detail some specific epilepsy syndromes that may show atypical prognosis as well as the general prognostic features of epilepsy.

Clinical and EEG factors associated with antiseizure medication resistance in idiopathic generalized epilepsy

OBJECTIVE

We sought to determine which combination of clinical and electroencephalography (EEG) characteristics differentiate between an antiseizure medication (ASM)-resistant vs ASM-responsive outcome for patients with idiopathic generalized epilepsy (IGE).

METHODS

This was a case-control study of ASM-resistant cases and ASM-responsive controls with IGE treated at five epilepsy centers in the United States and Australia between 2002 and 2018. We recorded clinical characteristics and findings from the first available EEG study for each patient. We then compared characteristics of cases vs controls using multivariable logistic regression to develop a predictive model of ASM-resistant IGE.

RESULTS

We identified 118 ASM-resistant cases and 114 ASM-responsive controls with IGE. First, we confirmed our recent finding that catamenial epilepsy is associated with ASM-resistant IGE (odds ratio [OR] 3.53, 95% confidence interval [CI] 1.32-10.41, for all study subjects) after covariate adjustment. Other independent factors seen with ASM resistance include certain seizure-type combinations (absence, myoclonic, and generalized tonic-clonic seizures [OR 7.06, 95% CI 2.55-20.96]; absence and generalized tonic-clonic seizures [OR 4.45, 95% CI 1.84-11.34]), as well as EEG markers of increased generalized spike-wave discharges (GSWs) in sleep (OR 3.43, 95% CI 1.12-11.36 for frequent and OR 7.21, 95% CI 1.50-54.07 for abundant discharges in sleep) and the presence of generalized polyspike trains (GPTs; OR 5.49, 95% CI 1.27-38.69). The discriminative ability of our final multivariable model, as measured by area under the receiver-operating characteristic curve, was 0.80.

SIGNIFICANCE

Multiple clinical and EEG characteristics independently predict ASM resistance in IGE. To improve understanding of a patient's prognosis, clinicians could consider asking about specific seizure-type combinations and track whether they experience catamenial epilepsy. Obtaining prolonged EEG studies to record the burden of GSWs in sleep and assessing for the presence of GPTs may provide additional predictive value.