Comorbid anxiety and depressive disorders in people with epilepsy (PWE) are highly prevalent and associated with various adverse outcomes. However, the prevalence of anxiety disorders in PWE across studies is highly variable. Our aim was to estimate the prevalence and moderating factors of anxiety and depressive disorders in PWE.Methods
Following prospective registration (PROSPERO; CRD42015027101), electronic databases were searched for studies that reported the prevalence of both anxiety and depressive disorders in samples of PWE up until July 2016. Data extracted included the prevalence of anxiety and depressive disorders, and moderators of interest (e.g., method of diagnosis, prevalence of drug-resistant epilepsy). Meta-analysis of the overall pooled prevalence of anxiety and depressive disorders was conducted.Results
The search yielded 8,636 unique articles, with 27 studies meeting final inclusion criteria (3,221 PWE). The pooled prevalence of anxiety and depressive disorders was 20.2% (95% confidence interval [CI] 15.3–26.0%) and 22.9% (95% CI 18.2–28.4%), respectively. Method of diagnosis significantly moderated anxiety disorder prevalence (Q statistic with one degree of freedom [Q1] = 36.29, p < 0.0001); the prevalence of anxiety disorders based on unstructured clinician assessment was 8.1% (95% CI 5.7–11.4%), compared to a prevalence of 27.3% (95% CI 22.1–33.3%) based on a structured clinical interview. There were no significant moderators of depressive disorder diagnosis.Significance
Findings suggest the prevalence of anxiety and depressive disorders in PWE are equivalent, and variability in prevalence of anxiety disorders across studies can be attributed partly to the method of diagnosis. These findings also challenge widely held assumptions that psychiatric comorbidity is more common in people with drug-resistant epilepsy. Future research should aim to improve the detection and management of these comorbidities in PWE, particularly anxiety disorders, which have remained relatively neglected.
Until now, it has been unclear if the three subsyndromes of adolescent-onset generalized genetic epilepsy (GGE) differ in long-term prognosis. Therefore, this study aimed to compare long-term seizure outcome in juvenile absence epilepsy (JAE), juvenile myoclonic epilepsy (JME), and epilepsy with generalized tonic–clonic seizures alone (EGTCS).Methods
This retrospective study is based on the archive of an institutional tertiary care outpatient clinic for adult patients with epilepsy. Charts of 870 epilepsy outpatients were reviewed among whom 176 had adolescent-onset GGE (53 JAE, 66 JME, 57 EGTCS). Median patient age at investigation was 60 years; median follow-up time was 42.5 years. If possible, GGE patients were additionally interviewed on psychosocial and clinical variables.Results
Age at first seizure was significantly higher in EGTCS patients (median 18 years) than in patients with JAE or JME (14 years each; p ≤ 0.001). Long-term seizure outcome hardly differed between the three subsyndromes. At the end of follow-up, 60% of all patients were in 5-year terminal seizure remission, and in 14%, epilepsy even had resolved (>10 years without seizures, >5 years without pharmacotherapy). Twenty percent of patients had persistent seizures during the last year of follow-up. Across all patients, 23% reported a psychiatric comorbidity, 87% had married, and 57% had achieved university entrance qualification.Significance
Long-term outcome was shown to be highly similar across all subsyndromes of adolescent-onset GGE. Even in a selection of difficult-to-treat epilepsy patients still attending an adult epilepsy clinic, most become seizure-free. To confirm these findings, prospective studies are needed.
It is well known that sleep-related motor seizures can originate from the temporal lobe. However, little is known about the clinical features of minor motor manifestations during sleep in patients with temporal lobe epilepsy. The main objective of our study was to verify the existence of minor motor events during sleep in patients with mesial temporal lobe epilepsy (MTLE) and to define their clinical features and electroencephalography (EEG) correlations.Methods
We enrolled in the study patients with diagnosis of symptomatic MTLE and a group of healthy controls. All patients and controls underwent long-term video -EEG monitoring, including at least one night of nocturnal sleep. We analyzed all the movements recorded during nocturnal sleep of patients and controls and their electroencephalographic correlations.Results
We analyzed the nocturnal sleep of 15 patients with symptomatic MTLE (8 males and 7 females; mean age ± standard deviation [SD]31.8 ± 14.9 years) and of 15 healthy controls (6 males and 9 females; mean age ± SD 32.8 ± 11.2 years). The analysis of movements during sleep revealed significant differences between groups, with the patients presenting significantly more movements in sleep than healthy controls (56.7 ± 39.2 vs. 15 ± 6.1; p < 0.001) with significant differences regarding oroalimentary automatisms, limb dystonia, straightening movements and gestural automatisms. EEG analysis showed that the proportion of movements preceded by EEG abnormalities was significantly higher in patients than in controls (57.8 ± 35.9 movements vs. 16.6 ± 13.4 movements; p < 0.001).Significance
The results of our study demonstrated the presence of minor motor events during sleep in patients with MTLE, suggesting an epileptic origin of these episodes. The study of nocturnal sleep in MTLE patients is useful in helping the clinicians in the diagnostic and therapeutic workup of these patients.
Psychiatric and behavioral disorders are important aspects of epilepsy and have received increasing attention in the last several years. The literature upon which most of the field relies contains some biases that must be carefully examined and resolved in future studies. First, in the pediatric epilepsy literature, many reports find that children with epilepsy have high levels of behavioral and psychiatric disorders when compared to appropriate controls. Most of these studies rely on parent-proxy completed instruments to assess these behavioral endpoints. Parents’ reports are not objective but reflect parents’ reactions and emotions. Increasing evidence suggests inherent biases in proxy reports and highlights the need to assess children directly. Second, periictal phenomena may be mischaracterized as underlying mood disorders. Third, many studies report elevated levels of psychiatric morbidity before and after the diagnosis of epilepsy, suggesting an inherent relation between the two types of disorders. Psychogenic nonepileptic seizures, while widely recognized as posing a diagnostic dilemma in the clinic, may account for some of these research findings. Diagnostic errors between epilepsy and psychogenic nonepileptic seizures need careful consideration when evaluating studies demonstrating associations between psychiatric disorders and epilepsy or poorer seizure control in association with psychiatric disorders in people who have epilepsy. Mental health concerns are important for everyone. An accurate, undistorted understanding of the relation between mental health disorders and epilepsy is essential to ensure appropriate therapy and to avoid unnecessary and potentially harmful treatments and common misconceptions.
Obstructive apnea due to laryngospasm links ictal to postictal events in SUDEP cases and offers practical biomarkers for review of past cases and prevention of new ones
Seizure spread into autonomic and respiratory brainstem regions is thought to play an important role in sudden unexpected death in epilepsy (SUDEP). As the clinical dataset of cases of definite SUDEP available for study grows, evidence points to a sequence of events that includes postictal apnea, bradycardia, and asystole as critical events that can lead to death. One possible link between the precipitating seizure and the critical postictal sequence is seizure-driven laryngospasm sufficient to completely obstruct the airway for an extended period, but ictal laryngospasm is difficult to fully assess. Herein, we demonstrate in a rat model how the electrical artifacts of attempts to inspire during airway obstruction and features of the cardiac rhythm establish this link between ictal and postictal activity and can be used as practical biomarkers of obstructive apnea due to laryngospasm or other causes of airway obstruction.
The mouse 6 Hz model of psychomotor seizures is a well-established and commonly used preclinical model for antiseizure drug (ASD) discovery. Despite its widespread use both in the identification and differentiation of novel ASDs in mice, a corresponding assay in rats has not been developed. We established a method for 6 Hz seizure induction in rats, with seizure behaviors similar to those observed in mice including head nod, jaw clonus, and forelimb clonus.Methods
A convulsive current that elicits these seizure behaviors in 97% of rats (CC97) was determined using a Probit analysis. Numerous prototype ASDs were evaluated in this model using stimulus intensities of 1.5× and 2× the CC97, which is comparable to the approach used in the mouse 6 Hz seizure model (e.g., 32 and 44 mA stimulus intensities). The ASDs evaluated include carbamazepine, clobazam, clonazepam, eslicarbazepine, ethosuximide, ezogabine, gabapentin, lacosamide, lamotrigine, levetiracetam, phenobarbital, phenytoin, rufinamide, tiagabine, topiramate, and sodium valproate. Median effective dose (ED50) and median toxic (motor impairment) dose (TD50) values were obtained for each compound.Results
Compounds that were effective at the 1.5 × CC97 stimulus intensity at protective index (PI) values >1 included clobazam, ethosuximide, ezogabine, levetiracetam, phenobarbital, and sodium valproate. Compounds that were effective at the 2 × CC97 stimulus intensity at PI values >1 included ezogabine, phenobarbital, and sodium valproate.Significance
In a manner similar to the use of the mouse 6 Hz model, development of a rat 6 Hz test will aid in the differentiation of ASDs, as well as in study design and dose selection for chronic rat models of pharmacoresistant epilepsy. The limited number of established ASDs with demonstrable efficacy at the higher stimulus intensity suggests that, like the mouse 6 Hz 44 mA model, the rat 6 Hz seizure model may be a useful screening tool for pharmacoresistant seizures.
Plasma cytokines associated with febrile status epilepticus in children: A potential biomarker for acute hippocampal injury
Our aim was to explore the association between plasma cytokines and febrile status epilepticus (FSE) in children, as well as their potential as biomarkers of acute hippocampal injury.Methods
Analysis was performed on residual samples of children with FSE (n = 33) as part of the Consequences of Prolonged Febrile Seizures in Childhood study (FEBSTAT) and compared to children with fever (n = 17). Magnetic resonance imaging (MRI) was obtained as part of FEBSTAT within 72 h of FSE. Cytokine levels and ratios of antiinflammatory versus proinflammatory cytokines in children with and without hippocampal T2 hyperintensity were assessed as biomarkers of acute hippocampal injury after FSE.Results
Levels of interleukin (IL)-8 and epidermal growth factor (EGF) were significantly elevated after FSE in comparison to controls. IL-1β levels trended higher and IL-1RA trended lower following FSE, but did not reach statistical significance. Children with FSE were found to have significantly lower ratios of IL-1RA/IL-1β and IL-1RA/IL-8. Specific levels of any one individual cytokine were not associated with FSE. However, lower ratios of IL-1RA/IL-1β, IL-1RA/1L-6, and IL-1RA/ IL-8 were all associated with FSE. IL-6 and IL-8 levels were significantly higher and ratios of IL-1RA/IL-6 and IL-1RA/IL-8 were significantly lower in children with T2 hippocampal hyperintensity on MRI after FSE in comparison to those without hippocampal signal abnormalities. Neither individual cytokine levels nor ratios of IL-1RA/IL-1β or IL-1RA/IL-8 were predictive of MRI changes. However, a lower ratio of IL-1RA/IL-6 was strongly predictive (odds ratio [OR] 21.5, 95% confidence interval [CI] 1.17–393) of hippocampal T2 hyperintensity after FSE.Significance
Our data support involvement of the IL-1 cytokine system, IL-6, and IL-8 in FSE in children. The identification of the IL-1RA/IL-6 ratio as a potential biomarker of acute hippocampal injury following FSE is the most significant finding. If replicated in another study, the IL-1RA/IL-6 ratio could represent a serologic biomarker that offers rapid identification of patients at risk for ultimately developing mesial temporal lobe epilepsy (MTLE).
Previous studies examining seizures in patients with 22q11.2 deletion syndrome (22q11.2DS) have focused primarily on children and adolescents. In this study we investigated the prevalence and characteristics of seizures and epilepsy in an adult 22q11.2DS population.Methods
The medical records of 202 adult patients with 22q11.2DS were retrospectively reviewed for documentation of seizures, electroencephalography (EEG) reports, and magnetic resonance imaging (MRI) findings. Epilepsy status was assigned in accordance with 2010 International League Against Epilepsy Classification.Results
Of 202 patients, 32 (15.8%) had a documented history of seizure. Of these 32, 23 (71.8%) had acute symptomatic seizures, usually associated with hypocalcemia and/or antipsychotic or antidepressant use. Nine patients (9/32, 28%; 9/202, 4%) met diagnostic criteria for epilepsy. Two patients had genetic generalized epilepsy; two patients had focal seizures of unknown etiology; two had epilepsy due to malformations of cortical development; in two the epilepsy was due to acquired structural changes; and in one patient the epilepsy could not be further classified.Significance
Similarly to children, the prevalence of epilepsy and acute symptomatic seizures in adults with 22q11.2DS is higher than in the general population. Hypocalcemia continues to be a risk factor for adults, but differently from kids, the main cause of seizures in adults with 22q11.2DS is exposure to antipsychotics and antidepressants. Further prospective studies are warranted to investigate how 22q11.2 microdeletion leads to an overall decreased seizure threshold.
Magnetic resonance imaging connectivity for the prediction of seizure outcome in temporal lobe epilepsy
Currently, approximately 60–70% of patients with unilateral temporal lobe epilepsy (TLE) remain seizure-free 3 years after surgery. The goal of this work was to develop a presurgical connectivity-based biomarker to identify those patients who will have an unfavorable seizure outcome 1-year postsurgery.Methods
Resting-state functional and diffusion-weighted 3T magnetic resonance imaging (MRI) was acquired from 22 unilateral (15 right, 7 left) patients with TLE and 35 healthy controls. A seizure propagation network was identified including ipsilateral (to seizure focus) and contralateral hippocampus, thalamus, and insula, with bilateral midcingulate and precuneus. Between each pair of regions, functional connectivity based on correlations of low frequency functional MRI signals, and structural connectivity based on streamline density of diffusion MRI data were computed and transformed to metrics related to healthy controls of the same age.Results
A consistent connectivity pattern representing the network expected in patients with seizure-free outcome was identified using eight patients who were seizure-free at 1-year postsurgery. The hypothesis that increased similarity to the model would be associated with better seizure outcome was tested in 14 other patients (Engel class IA, seizure-free: n = 5; Engel class IB-II, favorable: n = 4; Engel class III–IV, unfavorable: n = 5) using two similarity metrics: Pearson correlation and Euclidean distance. The seizure-free connectivity model successfully separated all the patients with unfavorable outcome from the seizure-free and favorable outcome patients (p = 0.0005, two-tailed Fisher's exact test) through the combination of the two similarity metrics with 100% accuracy. No other clinical and demographic predictors were successful in this regard.Significance
This work introduces a methodologic framework to assess individual patients, and demonstrates the ability to use network connectivity as a potential clinical tool for epilepsy surgery outcome prediction after more comprehensive validation.