Drug-resistant focal sleep related epilepsy: Results and predictors of surgical outcome

International League Against Epilepsy classification and definition of epilepsy syndromes with onset at a variable age: position statement by the ILAE Task Force on Nosology and Definitions

The goal of this paper is to provide updated diagnostic criteria for the epilepsy syndromes that have a variable age of onset, based on expert consensus of the International League Against Epilepsy Nosology and Definitions Taskforce (2017-2021). We use language consistent with current accepted epilepsy and seizure classifications and incorporate knowledge from advances in genetics, electroencephalography, and imaging. Our aim in delineating the epilepsy syndromes that present at a variable age is to aid diagnosis and to guide investigations for etiology and treatments for these patients.

Long-term Outcome of Epilepsy and Cortical Malformations Due to Abnormal Migration and Postmigrational Development: A Cohort Study

OBJECTIVE

To evaluate the long-term outcome of patients with epilepsy and malformations of cortical development (MCD).

METHODS

We conducted a historical cohort study of patients with epilepsy and MCD due to impaired neuronal migration and postmigration organization, and with a follow-up period of ≥5 years. For each patient, MCD was classified after accurate neuroimaging reappraisal by an expert neuroradiologist. The primary outcome was remission, defined as a period of seizure freedom ≥5 years at any time from epilepsy onset. We used Kaplan-Meier estimates for survival analysis, and univariate and multivariate Cox regression analyses to evaluate baseline variables as possible factors associated with remission.

RESULTS

The cohort included 71 patients (M/F=31/40) with a 17-year median follow-up (1506 person-years). About half (49.3%) had heterotopia, 35.2% polymicrogyria, 7% lissencephaly and 8.5% had the combination of two MCD. The mean age at seizure onset was 12.4±7.2 years. Intellectual disability and neurological deficits were observed in 30.4% and 40.9%, respectively. More than 60% of patients had refractory epilepsy. In three patients who underwent epilepsy surgery, MCD diagnosis was confirmed by histology. At last visit, 44% of patients had been seizure-free during the previous year, however none of them had stopped anti-seizure medication. Thirty patients achieved remission (Remission group, 42.2%) at some point in their disease history, whereas 41 individuals (Non Remission group, 57.8%) had never been in remission for ≥5 years. The cumulative remission rate was 38% by 20 years from inclusion. In the Cox model, unilateral distribution of MCD (HR: 2.68, 95% CI: 1.04-6.92) and a low seizure frequency at onset (HR: 5.01, 95% CI: 1.12-22.5) were significantly associated with remission.

CONCLUSIONS

Patients with epilepsy and MCD showed a remission rate of 38% by 20 years from onset. Unilateral distribution of the MCD is associated with a three-fold probability of achieving remission. About 40% of patients showed a drug-sensitive condition with risk of relapse during their epilepsy course.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that in patients with epilepsy and MCD, unilateral MCD and low seizure frequency at onset are associated with achieving epilepsy remission.

Focal cortical dysplasia links to sleep-related epilepsy in symptomatic focal epilepsy

OBJECTIVE

In sleep-related epilepsy (SRE), epileptic seizures predominantly occur during sleep, but the clinical characteristics of SRE remain elusive. We aimed to identify the clinical features associated with the occurrence of SRE in a large cohort of symptomatic focal epilepsy.

METHODS

We retrospectively included patients with four etiologies, including focal cortical dysplasia (FCD), low-grade tumors (LGT), temporal lobe epilepsy with hippocampal sclerosis (TLE-HS), and encephalomalacia. SRE was defined as more than 70% of seizures occurring during sleep according to the seizure diary. The correlation between SRE and other clinical variables, such as etiology of epilepsy, pharmacoresistance, seizure frequency, history of bilateral tonic-clonic seizures, and seizure localization was analyzed.

RESULTS

A total of 376 patients were included. Among them 95 (25.3%) were classified as SRE and the other 281(74.7%) as non-SRE. The incidence of SRE was 53.5% in the FCD group, which was significantly higher than the other three groups (LGT: 19.0%; TLE-HS: 9.9%; encephalomalacia: 16.7%; P < 0.001). The etiology of FCD (p < 0.001) was significantly associated with SRE (OR: 9.71, 95% CI: 3.35-28.14) as an independent risk factor. In addition, small lesion size (p = 0.009) of FCD further increased the risk of SRE (OR: 3.18, 95% CI: 1.33-7.62) in the FCD group.

SIGNIFICANCE

Our data highlight that FCD markedly increased the risk of sleep-related epilepsy independently of seizure localization. A small lesion of FCD further increased the risk of sleep-related epilepsy by 2.18 times in the FCD group.

Seizure Outcome After Surgery for MRI-Diagnosed Focal Cortical Dysplasia: A Systematic Review and Meta-analysis

OBJECTIVE

Focal cortical dysplasia (FCD) has been associated with poorer post-surgical seizure outcomes compared to other pathologies. FCD surgical series have been assembled on the basis of a histological diagnosis, including patients with abnormal as well as normal pre-operative MRI. However, in clinical workflow, patient selection for surgery is based on pre-operative findings, including MRI. We performed a systematic review and meta-analysis of the literature to determine the rate and predictors of favorable seizure outcome after surgery for MRI-detected FCD.

METHODS

We devised our study protocol in accordance with PRISMA guidelines and registered the protocol with PROSPERO. We searched MEDLINE, EMBASE, and Web of Science for studies of patients followed for ≥12 months after resective surgery for drug-resistant epilepsy with MRI-detected FCD. Random-effects meta-analysis was used to calculate the proportion of patients attaining a favorable outcome, defined as Engel Class I, ILAE Classes 1-2, or "seizure-free" status. Meta-regression was performed to investigate sources of heterogeneity.

RESULTS

Our search identified 3,745 references. Of these, 35 studies (total of 1,353 patients) were included. Most studies (89%) followed patients for ≥24 months post-surgery. The overall post-surgical favorable outcome rate was 70% (95% CI: 64-75). There was high inter-study heterogeneity. Favorable outcome was associated with complete resection of the FCD lesion [risk ratio, RR=2.42 (95% CI: 1.55-3.76), p<0.001] and location of the FCD lesion in the temporal lobe [RR=1.38 (95% CI: 1.07-1.79), p=0013], but not lesion extent, intracranial EEG use, or FCD histological type. The number of FCD histological types included in the same study accounted for 7.6% of the observed heterogeneity.

CONCLUSIONS

70% of patients with drug-resistant epilepsy and MRI features of FCD attain a favorable seizure outcome following resective surgery. Our findings can be incorporated in routine pre-operative counselling and reinforce the importance of resecting completely the MRI-detected FCD where this is safe and feasible.

Therapy in Sleep-Related Hypermotor Epilepsy (SHE)

PURPOSE OF REVIEW

The purpose of this review is to summarize and discuss current options and new advances in the treatment of sleep-related hypermotor epilepsy (SHE), focusing on pharmacological and surgical treatments.

RECENT FINDINGS

Carbamazepine (CBZ) has traditionally been regarded as the first-line treatment option in SHE patients. In patients showing an unsatisfactory response to monotherapy, topiramate (TPM), lacosamide (LCM) and acetazolamide (ACZ) could be reasonable add-on strategies. The increasing understanding of the role of neuronal nicotinic acetylcholine receptor (nAChR) in SHE pathophysiology has led to the evaluation of compounds able to modulate this receptor system, including nicotine patches and fenofibrate. Despite polytherapy with two or more antiepileptic drugs (AEDs), about one-third of SHE patients suffer from drug-resistant seizures. In selected drug-resistant patients, epilepsy surgery is a therapeutic approach that offers high probability of recovery, with up to two-third of patients becoming seizure-free after resection of the epileptogenic zone. An evidence-based approach from randomized placebo-controlled trials in SHE patients is lacking, and current treatment recommendations are based only on case reports and small series. Furthermore, most of these case reports and case series involve patients with a known genetic defect, which only accounts for a small proportion of SHE patients. Therefore, a prospective study in a large cohort of sporadic SHE patients is necessary in order to provide clinicians with an evidence-based treatment for this rare form of epilepsy. An early and effective anti-epileptic treatment is mandatory for SHE patients, in order to prevent the risk of increasing seizure frequency throughout the disease course with relevant impact on patients' cognitive profile and daytime performances.

Sleep Related Epilepsy and Pharmacotherapy: An Insight

In the last several decades, sleep-related epilepsy has drawn considerable attention among epileptologists and neuroscientists in the interest of new paradigms of the disease etiology, pathogenesis and management. Sleep-related epilepsy is nocturnal seizures that manifest solely during the sleep state. Sleep comprises two distinct stages i.e., non-rapid eye movement (NREM) and rapid eye movement (REM) that alternate every 90 min with NREM preceding REM. Current findings indicate that the sleep-related epilepsy manifests predominantly during the synchronized stages of sleep; NREM over REM stage. Sleep related hypermotor epilepsy (SHE), benign partial epilepsy with centrotemporal spikes or benign rolandic epilepsy (BECTS), and Panayiotopoulos Syndrome (PS) are three of the most frequently implicated epilepsies occurring during the sleep state. Although some familial types are described, others are seemingly sporadic occurrences. In the present review, we aim to discuss the predominance of sleep-related epilepsy during NREM, established familial links to the pathogenesis of SHE, BECTS and PS, and highlight the present available pharmacotherapy options.

Coregistrating magnetic source and magnetic resonance imaging for epilepsy surgery in focal cortical dysplasia

Background

Epilepsy surgery for focal cortical dysplasia type II (FCD II) offers good chances for seizure freedom, but remains a challenge with respect to lesion detection, defining the epileptogenic zone and the optimal resection strategy. Integrating results from magnetic source imaging from magnetoencephalography (MEG) with magnetic resonance imaging (MRI) including MRI postprocessing may be useful for optimizing these goals.

Methods

We here present data from 21 adult FCD II patients, investigated during a 10 year period and evaluated including magnetic source imaging. 16 patients had epilepsy surgery, i.e. histopathologically verified FCD II, and a long follow up. We present our analysis of epileptogenic zones including MEG in relation to structural data according to MRI data and relate these results to surgical outcomes.

Results

FCD II in our cohort was characterized by high MEG yield and localization accuracy and MEG showed impact on surgical success-rates. MEG source localizations were detected in 95.2% of patients and were as close as 12.3 ± 8,1 mm to the MRI-lesion. After a mean follow up of >3 years, we saw >80% Engel I outcomes, with more favourable outcomes when the MEG source was completely resected (Fishers exact test 0,033).

Conclusion

We argue for a high value of conducting a combined MEG-MRI approach in the presurgical workup and the resection strategy in patients with FCD II related epilepsy.

Small Lesion Size Is Associated with Sleep-Related Epilepsy in Focal Cortical Dysplasia Type II

Objective

To investigate the neuroimaging and clinical features associated with sleep-related epilepsy (SRE) in patients with focal cortical dysplasia (FCD) type II.

Methods

Patients with histopathologically proven FCD type II were included from three epilepsy centers. SRE was defined according to the video EEG findings and seizure history. Cortical surface reconstruction and volume calculation were performed using FreeSurfer. The lesions were manually delineated on T1 volumetric MRI using the ITK-SNAP software. The lesion volumes were normalized by the intracranial volume of each patient. The lesions were classified as small or large by placing a threshold based on quantitative (whether the lesion was detected on MRI report) and qualitative (volume) criteria.

Results

A total of 77 consecutive patients were included. Of them, 36 had SRE and 41 had non-SRE. An earlier age of epilepsy onset, high seizure frequency, regional interictal EEG findings, and favorable surgical outcome were characteristic in both groups. Small lesions were defined as those having a volume <3,217 mm³. In total, 60.9% of the patients with SRE (25/41) had small FCD lesion, which was significantly higher than the non-SRE group (9/34, 26.5%, p = 0.005). Small lesion size was the only predictor significantly associated with SRE in the overall type II group by multivariate analyses (p = 0.016). Although the proportion of patients who had frontal FCD and SRE was higher than non-frontal FCD (54.5 vs. 27.3%, p = 0.043), the relationship between SRE and lesion location was not confirmed by multivariate analysis. Thalamic volume and seizure semiology were not statistically different between the SRE and non-SRE group. The significant association between lesion size and SRE was reproducible in type IIb and IIa subgroups.

Significance

SRE is common in patients with FCD type II. Small FCD type II lesions are significantly associated with SRE. Although our findings cannot be applied to the entire spectrum of SRE, potential existence of small FCD lesions should be considered when evaluating patients with SRE, and utilization of all other supportive electroclinical information for lesion detection is highly desirable.

The Mutual Interaction Between Sleep and Epilepsy on the Neurobiological Basis and Therapy

BACKGROUND

Sleep and epilepsy are mutually related in a complex, bidirectional manner. However, our understanding of this relationship remains unclear.

RESULTS

The literatures of the neurobiological basis of the interactions between sleep and epilepsy indicate that non rapid eye movement sleep and idiopathic generalized epilepsy share the same thalamocortical networks. Most of neurotransmitters and neuromodulators such as adenosine, melatonin, prostaglandin D2, serotonin, and histamine are found to regulate the sleep-wake behavior and also considered to have antiepilepsy effects; antiepileptic drugs, in turn, also have effects on sleep. Furthermore, many drugs that regulate the sleep-wake cycle can also serve as potential antiseizure agents. The nonpharmacological management of epilepsy including ketogenic diet, epilepsy surgery, neurostimulation can also influence sleep.

CONCLUSION

In this paper, we address the issues involved in these phenomena and also discuss the various therapies used to modify them.

Sleep-related hypermotor epilepsy: prevalence, impact and management strategies

Sleep-related hypermotor epilepsy (SHE), previously called nocturnal frontal lobe epilepsy (NFLE), is a focal epilepsy characterized by asymmetric tonic/dystonic posturing and/or complex hyperkinetic seizures occurring mostly during sleep. SHE fulfills the definition of rare disease with an estimated minimum prevalence of 1.8/100,000 individuals, and it represents about 10% of drug-resistant surgical cases. Although SHE and autosomal-dominant SHE (ADSHE) have been considered benign epileptic conditions for a long time, emerging data have shed light on the severity of this disorder and some peculiar features can impact negatively on the quality of life of SHE patients. In fact, seizure frequency can be very high, resulting in nocturnal sleep fragmentation with possible diurnal consequences such as excessive sleepiness and fatigue. Moreover, recent studies, adopting a systematic neuropsychological assessment, have shown deficits in memory, executive functions and visuo-spatial abilities in almost half of SHE patients. Intellectual disabilities and psychiatric disorders have also been reported in some genetic forms. SHE may also exert a negative effect on health-related quality of life, especially in domains pertaining to a patient's role in the family, social context and patient's illness experience. Despite a good response to pharmacological treatment, especially with carbamazepine, 30% of SHE patients suffer from drug-resistant seizures. Finally, recent studies suggest a poor prognosis in a high percentage of SHE patients with a 20.4% cumulative probability of achieving terminal remission at 10 years from onset. For selected drug-resistant SHE patients, epilepsy surgery is the only treatment offering high probability of recovery, both for seizures and for epilepsy-related sleep alterations.

Sleep-related hypermotor epilepsy: Long-term outcome in a large cohort

OBJECTIVE

To assess the long-term outcome of sleep-related hypermotor epilepsy (SHE).

METHODS

We retrospectively reconstructed a representative cohort of patients diagnosed with SHE according to international diagnostic criteria, sleep-related seizures ≥75% and follow-up ≥5 years. Terminal remission (TR) was defined as a period of ≥5 consecutive years of seizure freedom at the last follow-up. We used Kaplan-Meier estimates to calculate the cumulative time-dependent probability of TR and to generate survival curves. Univariate and multivariate Cox regression analyses were performed.

RESULTS

We included 139 patients with a 16-year median follow-up (2,414 person-years). The mean age at onset was 13 ± 10 years. SHE was sporadic in 86% of cases and familial in 14%; 16% of patients had underlying brain abnormalities. Forty-five percent of patients had at least 1 seizure in wakefulness lifetime and 55% had seizures only in sleep (typical SHE). At the last assessment, 31 patients achieved TR (TR group, 22.3%), while 108 (NTR group, 77.7%) still had seizures or had been in remission for <5 years. The cumulative TR rate was 20.4%, 23.5%, and 28.4% by 10, 20, and 30 years from inclusion. At univariate analysis, any underlying brain disorder (any combination of intellectual disability, perinatal insult, pathologic neurologic examination, and brain structural abnormalities) and seizures in wakefulness were more frequent among the NTR group (p = 0.028; p = 0.043). Absence of any underlying brain disorder (hazard ratio 4.21, 95% confidence interval 1.26-14.05, p = 0.020) and typical SHE (hazard ratio 2.76, 95% confidence interval 1.31-5.85, p = 0.008) were associated with TR.

CONCLUSIONS

Our data show a poor prognosis of SHE after a long-term follow-up. Its outcome is primarily a function of the underlying etiology.

A longitudinal study of surgical outcome of pharmacoresistant epilepsy caused by focal cortical dysplasia

This study aimed to determine the long-term surgical outcome of pharmacoresistant epilepsy caused by focal cortical dysplasia (FCD) and to identify the important predictors of the favorable surgical outcome. The study retrospectively analyzed the data of pharmacoresistant epilepsy patients with histologically proven FCD in our epilepsy center from May 2010 to December 2014. It included 120 patients with a mean follow-up of 34.6 months. Survival analysis and multivariate regression with Cox proportional hazards model were used to evaluate the rate, stability, and predictors of seizure freedom. The estimated chance of seizure freedom was 73.0 % [95 % confidence intervals (CI), 65.2-80.8 %] at 1 year after surgery, 70.0 % (95 % CI, 62.2-77.8 %) at 2 years, and 65 % (95 % CI, 53.2-76.7 %) at 5 years and beyond. Most seizure recurrences (85.7 %) happened within 12 months after surgery. The incomplete resection of FCD, presence of interictal epileptiform discharges (IEDs) on 3-6 months postoperative electroencephalography (EEG), and presence of habitual acute postoperative seizure (APOS) were independent predictors of seizure recurrence. However, other factors, such as the FCD type and sleep-related epilepsy, did not significantly influence the surgical outcome. Before becoming pharmacoresistant epilepsy, 30 (25 %) patients responded to antiepileptic drugs with a seizure-free duration of more than 1 year. The surgical outcome is favorable in patients with FCD, which is comparable to that reported in developed countries. The incomplete resection of FCD, presence of IEDs on 3-6 months postoperative EEG, and presence of habitual APOS are powerful predictive factors for seizure recurrence after surgery.