Mortality in Dravet syndrome: A review.

INTRODUCTION: Premature mortality is a major issue in Dravet syndrome (DS). To improve understanding of DS premature mortality, we conducted a comprehensive literature search with a particular emphasis on SUDEP. METHODS: We searched PubMed, Embase, Web of Science, Cochrane, CENTRAL, CINAHL, PsycINFO, Academic Search Premier, and ScienceDirect on the following terms: "Dravet syndrome", "severe myoclonic epilepsy", "SMEI", "mortality", "survivors", "prognosis", and "death". DS cases or cohorts studies reporting mortality were included. RESULTS: The search yielded 676 articles and 86 meeting abstracts. After removing duplicates and screening titles and abstracts, full text of 73 articles was reviewed. Only 28 articles and six meeting abstracts met inclusion criteria. Five articles and four meeting abstracts were excluded, as the case(s) were also described elsewhere. After checking the references, five additional studies were included. The 30 items reported 177 unique cases. Sudden unexpected death in epilepsy was the likely cause in nearly half of the cases (n=87, 49%), followed by status epilepticus (n=56, 32%). Drowning or accidental death was reported in 14 cases (8%), infections in 9 (5%), other causes in six (3%), and unknown in five (3%). Age at death was reported for 142 of the 177 cases (80%), with a mean age of 8.7±9.8years (SD); 73% died before the age of 10years. DISCUSSION: Dravet syndrome is characterized by high epilepsy-related premature mortality and a marked young age at death. Sudden unexpected death in epilepsy is the leading reported cause of death in DS, accounting for nearly half of all deaths. The cause of this excess mortality remains elusive but may be explained by epilepsy severity, as well as genetic susceptibility to SUDEP.

Adults with a history of possible Dravet syndrome: an illustration of the importance of analysis of the SCN1A gene.

Most patients with Dravet syndrome have de novo mutations in the neuronal voltage-gated sodium channel type 1 (SCN1A) gene. We report on two unrelated fathers with severe childhood epilepsy compatible with a possible diagnosis of Dravet syndrome, who both have a child with Dravet syndrome. Analysis of the SCN1A gene revealed a pathogenic mutation in both children. One father exhibited somatic mosaicism for the mutation detected in his son. A relatively favorable cognitive outcome in patients with Dravet syndrome patients may be explained by somatic mosaicism for the SCN1A mutation in brain tissue. A mild form of Dravet syndrome in adult patients is associated with a high recurrence risk and possibly a more severe epilepsy phenotype in their offspring.

Cardiac arrhythmias in Dravet syndrome: an observational multicenter study.

OBJECTIVES: We ascertained the prevalence of ictal arrhythmias to explain the high rate of sudden unexpected death in epilepsy (SUDEP) in Dravet syndrome (DS). METHODS: We selected cases with clinical DS, ≥6 years, SCN1A mutation, and ≥1 seizure/week. Home-based ECG recordings were performed for 20 days continuously. Cases were matched for age and sex to two epilepsy controls with no DS and ≥1 major motor seizure during video-EEG. We determined the prevalence of peri-ictal asystole, bradycardia, QTc changes, and effects of convulsive seizures (CS) on heart rate, heart rate variability (HRV), and PR/QRS. Generalized estimating equations were used to account for multiple seizures within subjects, seizure type, and sleep/wakefulness. RESULTS: We included 59 cases. Ictal recordings were obtained in 45 cases and compared to 90 controls. We analyzed 547 seizures in DS (300 CS) and 169 in controls (120 CS). No asystole occurred. Postictal bradycardia was more common in controls (n = 11, 6.5%) than cases (n = 4, 0.7%; P = 0.002). Peri-ictal QTc-lengthening (≥60ms) occurred more frequently in DS (n = 64, 12%) than controls (n = 8, 4.7%, P = 0.048); pathologically prolonged QTc was rare (once in each group). In DS, interictal HRV was lower compared to controls (RMSSD P = 0.029); peri-ictal values did not differ between the groups. Prolonged QRS/PR was rare and more common in controls (QRS: one vs. none; PR: three vs. one). INTERPRETATION: We did not identify major arrhythmias in DS which can directly explain high SUDEP rates. Peri-ictal QTc-lengthening was, however, more common in DS. This may reflect unstable repolarization and an increased propensity for arrhythmias.

Add-on levetiracetam in children and adolescents with refractory epilepsy: results of an open-label multi-centre study.

PURPOSE: To study the efficacy and tolerability of add-on levetiracetam in children and adolescents with refractory epilepsy. METHODS: In this prospective multi-centre, open-label, add-on study, 33 children aged 4-16 years (median 8.5 years) with epilepsy refractory to at least two antiepileptic drugs were treated with levetiracetam in addition to their present treatment regimen with a follow-up of 26 weeks. The starting dose of 10 mg/kg/day was increased with 2-week steps of 10 mg/kg/day, if necessary, up to a maximum dose of 60 mg/kg/day. RESULTS: Retention rate was 69.7% after 26 weeks on a median levetiracetam dosage of 22 mg/kg/day. Four children dropped-out because levetiracetam was ineffective, four because seizure frequency increased and/or seizures became more severe, and two because they developed aggressive behaviour. Compared to their baseline seizure frequency, 13 children (39.4%) had a >50% seizure reduction 12 weeks after initiation of levetiracetam, and 17 children (51.5%) at 26 weeks. At 26 weeks, nine children (27.3%) had been seizure-free for at least the last 4 weeks, terminal remission ranged from 0 to 187 days (mean 46 days). Levetiracetam was effective in both partial and primary generalized seizures, but had most effect in partial seizures. Most reported side effects were hyperactivity (48.5%), somnolence (36.4%), irritability (33.3%) and aggressive behaviour (27.3%). Severity of most side effects was mild. Five children had a serious adverse event, which all concerned hospital admissions that were not related to levetiracetam use. CONCLUSION: Levetiracetam proved to be an effective and well-tolerated add-on treatment in this group of children with refractory epilepsy.

Effect of melatonin on sleep, behavior, and cognition in ADHD and chronic sleep-onset insomnia.

OBJECTIVE: To investigate the effect of melatonin treatment on sleep, behavior, cognition, and quality of life in children with attention-deficit/hyperactivity disorder (ADHD) and chronic sleep onset insomnia. METHOD: A total of 105 medication-free children, ages 6 to 12 years, with rigorously diagnosed ADHD and chronic sleep onset insomnia participated in a randomized, double-blind, placebo-controlled trial using 3 or 6 mg melatonin (depending on body weight), or placebo for 4 weeks. Primary outcome parameters were actigraphy-derived sleep onset, total time asleep, and salivary dim light melatonin onset. RESULTS: Sleep onset advanced by 26.9 +/- 47.8 minutes with melatonin and delayed by 10.5 +/- 37.4 minutes with placebo (p < .0001). There was an advance in dim light melatonin onset of 44.4 +/- 67.9 minutes in melatonin and a delay of 12.8 +/- 60.0 minutes in placebo (p < .0001). Total time asleep increased with melatonin (19.8 +/- 61.9 minutes) as compared to placebo (-13.6 +/- 50.6 minutes; p = .01). There was no significant effect on behavior, cognition, and quality of life, and significant adverse events did not occur. CONCLUSION: Melatonin advanced circadian rhythms of sleep-wake and endogenous melatonin and enhanced total time asleep in children with ADHD and chronic sleep onset insomnia; however, no effect was found on problem behavior, cognitive performance, or quality of life.

Photosensitivity in Dravet syndrome is under-recognized and related to prognosis.

OBJECTIVE: To detect determinants for photoparoxysmal EEG response (PPR) in SCN1A-related Dravet syndrome (DS). METHODS: Data were studied from nationwide medical histories and EEGs of DS-patients (n=53; 31 males, age 2-19years). Detailed questionnaires on visual stimuli were completed by parents (n=49). RESULTS: PPR was found in 22 patients (42%; median age 1.25yr), and repeatedly in 17%. PPR (17% of 249 intermittent photic stimulation (IPS)-EEGs) occurred more often with optimal IPS protocols (OR 2.11 [95%CI 1.09-4.13]) and in EEGs showing spontaneous epileptiform abnormalities (OR 5.08 [95%CI 2.05-12.55]). PPR-positive patients tended to be younger at first (p=0.072) and second seizure (p=0.049), showed severe intellectual disability (p=0.042), and had more often spontaneous occipital epileptiform abnormalities (p<0.001). Clinical sensitivity was reported in medical files in 22% of patients and by parents in 43% (self-induction 24%). Clinical or EEG proven visual sensitivity was detected in 65% of cases. CONCLUSIONS: Sensitivity to visual stimuli is very common in DS and more often noticed by parents than confirmed by EEG. Detection of PPR improves with repetitive tests using accurate IPS protocols. SIGNIFICANCE: Photosensitivity is an important feature in DS and seems to be a marker of the severity of the disorder. Therefore repeated standardized IPS should be encouraged.

Repeated administration of D-amphetamine induces loss of [123I]FP-CIT binding to striatal dopamine transporters in rat brain: a validation study.

UNLABELLED: In recent years, several PET and SPECT studies have shown loss of striatal dopamine transporter (DAT) binding in amphetamine (AMPH) users. However, the use of DAT SPECT tracers to detect AMPH-induced changes in DAT binding has not been validated. We therefore examined if repeated administration of D-AMPH or methamphetamine (METH) may induce loss of binding to striatal DATs in rats by using an experimental biodistribution study design and a SPECT tracer for the DAT ([123I]FP-CIT). METHODS: Groups of male rats (n = 10 per group) were treated with D-AMPH (10 mg/kg body weight), METH (10 mg/kg body weight), or saline, twice a day for 5 consecutive days. Five days later, [123I]FP-CIT was injected intravenously, and 2 h later, the rats were sacrificed and radioactivity was assayed. RESULTS: In d-AMPH but not METH-treated rats, striatal [123I]FP-CIT uptake was significantly lower (approximately 17%) than in the control group. CONCLUSION: These data show that [123I]FP-CIT can be used to detect AMPH-induced changes in DAT binding and may validate the use of DAT radiotracers to study AMPH-induced changes in striatal DAT binding in vivo.

Idiopathic chronic sleep onset insomnia in attention-deficit/hyperactivity disorder: a circadian rhythm sleep disorder.

To investigate whether ADHD-related sleep-onset insomnia (SOI) is a circadian rhythm disorder, we compared actigraphic sleep estimates, the circadian rest-activity rhythm, and dim light melatonin onset (DLMO) in ADHD children having chronic idiopathic SOI with that in ADHD children without sleep problems. Participants were 87 psychotropic-medication-naïve children, aged 6 to 12 yrs, with rigorously diagnosed ADHD and SOI (ADHD-SOI) and 33 children with ADHD without SOI (ADHD-noSOI) referred from community mental health institutions and pediatric departments of non-academic hospitals in The Netherlands. Measurements were 1 wk, 24 h actigraphy recordings and salivary DLMO. The mean (+/-SD) sleep onset time was 21:38 +/- 0:54 h in ADHD-SOI, which was significantly (p < 0.001) later than that of 20:49 +/- 0:49 h in ADHD-noSOI. DLMO was significantly later in ADHD-SOI (20:32 +/- 0:55 h), compared with ADHD-noSOI (19:47 +/- 0:49 h; p < 0.001). Wake-up time in ADHD-SOI was later than in ADHD-noSOI (p = 0.002). There were no significant between-group differences in sleep maintenance, as estimated by number of wake bouts and activity level in the least active 5 h period, or inter- and intradaily rhythm variability. We conclude that children with ADHD and chronic idiopathic sleep-onset insomnia show a delayed sleep phase and delayed DLMO, compared with ADHD children without SOI.

Effect of vaccinations on seizure risk and disease course in Dravet syndrome.

OBJECTIVE: To study the effect of vaccination-associated seizure onset on disease course and estimate the risk of subsequent seizures after infant pertussis combination and measles, mumps, and rubella (MMR) vaccinations in Dravet syndrome (DS). METHODS: We retrospectively analyzed data from hospital medical files, child health clinics, and the vaccination register for children with DS and pathogenic SCN1A mutations. Seizures within 24 hours after infant whole-cell, acellular, or nonpertussis combination vaccination or within 5 to 12 days after MMR vaccination were defined as "vaccination-associated." Risks of vaccination-associated seizures for the different vaccines were analyzed in univariable and in multivariable logistic regression for pertussis combination vaccines and by a self-controlled case series analysis using parental seizure registries for MMR vaccines. Disease courses of children with and without vaccination-associated seizure onset were compared. RESULTS: Children who had DS (n = 77) with and without vaccination-associated seizure onset (21% and 79%, respectively) differed in age at first seizure (median 3.7 vs 6.1 months, p < 0.001) but not in age at first nonvaccination-associated seizure, age at first report of developmental delay, or cognitive outcome. The risk of subsequent vaccination-associated seizures was significantly lower for acellular pertussis (9%; odds ratio 0.18, 95% confidence interval [CI] 0.05-0.71) and nonpertussis (8%; odds ratio 0.11, 95% CI 0.02-0.59) than whole-cell pertussis (37%; reference) vaccines. Self-controlled case series analysis showed an increased incidence rate ratio of seizures of 2.3 (95% CI 1.5-3.4) within the risk period of 5 to 12 days following MMR vaccination. CONCLUSIONS: Our results suggest that vaccination-associated earlier seizure onset does not alter disease course in DS, while the risk of subsequent vaccination-associated seizures is probably vaccine-specific.

Recurrent schizophrenia-like psychosis as first manifestation of epilepsy: a diagnostic challenge in neuropsychiatry.

Since the 1950s, several studies have been carried out to investigate the occurrence of schizophrenia-like psychoses in epilepsy. The psychopathological profile comprises symptoms from the affective, schizophrenic, and cognitive domains and the prevalence varies between 2% to 20%. Classification of such conditions is performed according to their temporal relationship with the seizure itself. Although it is well known that epilepsy may be associated with psychotic disorders, it is less widely recognized that relapsing psychotic phenomena may be the first and only symptom of epilepsy. In this research, two patients are described who were initially referred for recurrent episodes of bipolar affective disorder and schizophrenic psychosis, respectively. In both patients, a diagnosis of relapsing postictal psychotic states due to previously undiagnosed epilepsy was made and consequently, treatment with antiepileptics was started. During follow up over several months, they remained free of both epileptic and psychotic symptoms. Given the kaleidoscopic nature of the postictal psychosis and full recovery from this, such psychoses best meet the criteria for a cycloid psychosis. These observations illustrate diagnostic and therapeutic pitfalls due to the conceptual disintegration emerging from the inadequate separation between psychiatry and neurology. Therefore, the importance of a neuropsychiatric viewpoint should be promoted.

Sleep hygiene and actigraphically evaluated sleep characteristics in children with ADHD and chronic sleep onset insomnia.

In the present study we investigated sleep hygiene and actigraphically evaluated sleep in 74 medication-naïve children, aged 6-12 years, with rigorously diagnosed attention-deficit/hyperactivity disorder (ADHD) and chronic sleep onset insomnia (ADHD-SOI) and 23 ADHD controls without insomnia (ADHD-noSOI). Between-group differences were analysed for lights out (sleep log), actigraphically evaluated sleep onset, sleep latency, total sleep duration, actual sleep time and sleep hygiene as measured with the Children's Sleep Hygiene Scale. We found a significant difference (P < 0.001) in mean (+/-SD) sleep onset between the ADHD-SOI group (21:49 +/- 0:56 h) and ADHD-noSOI groups (20:41 +/- 0:45 h). Sleep latency was significantly (P < 0.001) longer in ADHD-SOI (00:53 +/- 0:25 h) compared to ADHD-noSOI (00:26 +/- 0:25 h). The difference in total sleep duration between ADHD-SOI (9:42 +/- 0:44 h) and ADHD-noSOI (10:09 +/- 0:43 h) was not significantly different (P = 0.18). The group difference in actual sleep time was also not significant (8:43 +/- 0:52 h in ADHD-SOI versus 9:13 +/- 1:16 h; P = 0.40). There was no significant difference (P = 0.17) in mean (+/-SD) total sleep hygiene score between the ADHD-SOI (56.4 +/- 10.5) and ADHD-noSOI groups (53.0 +/- 10.6). We conclude that there were differences in sleep onset and sleep latency in ADHD children with chronic SOI and those without insomnia; however, sleep hygiene practices were similar and did not relate to sleep characteristics.

Neurochemical markers of alcoholism vulnerability in humans.

This review considers several neurochemical characteristics or trait markers that may be related to a genetic vulnerability to alcoholism. These potential neurochemical markers of alcoholism vulnerability include indices of activity of five neurotransmitter systems, namely gamma-aminobutyric acid, serotonin, dopamine, noradrenaline and beta-endorphin. This review evaluates whether potential abnormalities in these neurochemical indices, as assessed in alcoholics and in the children of alcoholics, meet three criteria for the identification of a vulnerability marker of alcoholism: (1). heritable; (2). associated with alcoholism in the general population; (3). state independent. It is concluded that, at present, indices of increased baseline activity of the serotonin transporter in platelets and of increased responsiveness of the pituitary beta-endorphin system may fulfil each of these three criteria. Additional research efforts should be devoted to the evaluation of trait marker properties of neurochemical indices in individuals at high risk for alcoholism.