Drug-resistant idiopathic generalized epilepsy: A meta-analysis of prevalence and risk factors

BACKGROUND

Idiopathic generalized epilepsy (IGE) is a common epilepsy syndrome with early age onset and generally good seizure outcomes. This study aims to determine the incidence and predictive risk factors for drug-resistant IGE.

METHODS

We systematically searched three databases (PubMed, Embase, and Cochrane Library) in November 2022 and included 12 eligible studies which reported long-term outcomes (mean = 14.05) after antiseizure medications (ASMs) from 2001 to 2020. We defined drug resistance as the persistence of any seizure despite ASMs treatment (whether as monotherapies or in combination) given the criteria of drug resistance varied in original studies. A random-effects model was used to evaluate the prevalence of refractory IGE. Studies reporting potential poor prognostic factors were included for subsequent subgroup meta-analysis.

RESULTS

The pooled prevalence of drug resistance in IGE cohorts was 27% (95% CI: 0.19-0.36). Subgroup analysis of the risk factors revealed that the psychiatric comorbidities (odds ratio (OR): 4.87, 95% confidence interval (CI): 2.97-7.98), combined three seizure types (absences, myoclonic jerks, and generalized tonic-clonic seizures) (OR: 5.37, 95% CI: 3.16-9.13), the presence of absence seizure (OR: 4.38, 95% CI: 2.64-7.28), generalized polyspike trains (GPT) (OR: 4.83, 95% CI: 2.42-9.64), sex/catamenial epilepsy (OR: 3.25, 95% CI: 1.97-5.37), and status epilepticus (OR: 5.94, 95% CI: 2.23-15.85) increased the risk of poor prognosis. Other factors, including age onset, family history, and side effects of ASMs, were insignificantly associated with a higher incidence of refractory IGE.

CONCLUSION

Drug resistance is a severe complication of IGE. Further standardized research about clinical and electroencephalography factors is warranted.

Seizure Analysis Presented to Emergency Department in Saudi Arabia: New VS Chronic Cases

Background

Epilepsy, characterized by recurrent unprovoked seizures, poses a significant global burden on individuals and healthcare systems. Accurate identification of underlying causes is vital for optimal intervention. However, studies reveal a lack of standardized approaches, potentially resulting in unnecessary investigations.

Objective

We aimed to highlight the importance of avoiding unnecessary testing to minimize healthcare costs and resource waste.

Methods

In the Emergency Department of King Fahd Hospital of the University (KFUH) in Alkhobar, a retrospective cross-sectional study encompassed 190 patients presenting with seizures from January 1, 2020, to December 31, 2022. The study aimed to elucidate the epidemiological profile and distinguish clinical and demographic factors between new onset seizures and known cases.

Results

The study included 190 epilepsy cases, with 51.1% known and 48.9% new onset. Generalized tonic-clonic seizures were prominent (43.2%), and non-compliance (24.2%) was a leading cause. New onset seizures were associated with abnormal CT findings (p=0.025), drug use (74.2%), and intoxication (6.5%). Demographically, Saudis showed higher new onset prevalence (82.8%, p=0.001).

Conclusion

The average length of stay was 5.93 hours, and the distribution of new vs. known cases was nearly equal among the 190 patients. Laboratory findings showed no significant associations with either group, mostly falling within the normal range. To optimize care further, we recommend continued refinement of protocols, emphasis on medication compliance.

The burden of disease of idiopathic/genetic generalized epilepsy - A nationwide online survey

The aim of the study was to assess the self-reported burden of disease in people with idiopathic/genetic generalized epilepsy and risk factors associated with high disease burden. We performed a nationwide online survey on epilepsy characteristics/treatment, quality of life/daily living followed by Standardized Assessment of Personality-Abbreviated Scale, Major Depression Inventory, Barratt Impulsiveness Scale (brief) and the brief Epilepsy Anxiety Survey Instrument. The survey was sent to 275 representative patients with IGE ('Funen cohort') and later publicly distributed via the Danish Epilepsy Association. The characteristics of the responders of the 'Funen cohort' (n = 119) did not differ from non-responders and previously assessed data. Out of 753 persons accessing the public survey, 167 had probable IGE. As compared to the 'Funen cohort', patients from the public survey reported similar age, time since last seizure, years with disease, seizure types, and IGE syndromes but more current and previously tried anti-seizure medications (ASMs). In both cohorts, patients had higher scores for depression, impulsivity, and personality disorders as compared to Danish normal values irrespective of seizure control or medication. Higher depression and anxiety scores but neither impulsivity nor personality disorders were associated with ongoing seizures. Overall health condition was estimated as bad by 28%. In the last four weeks, 20.4% reported limitations of activities of daily living due to epilepsy; 27.8% felt fed up because of their epilepsy. Patients with high subjective disease burden had more current ASMs, shorter time since last seizure and increased scores for depression, anxiety, impulsivity, and personality disorders. In conclusion, having IGE was associated with higher scores for impulsivity, depression, and personality disorders irrespective of seizure control and current treatment. High subjective disease burden was common and associated with ongoing seizures, absence/myoclonic seizures and high scores for impulsivity, depression, anxiety, and personality disorders.

Obstructive sleep apnea risk in patients with focal versus generalized epilepsy

OBJECTIVE

Obstructive sleep apnea (OSA) is common in patients with epilepsy (PWE), and treatment may improve seizure control. However, OSA is often undiagnosed in PWE, and understanding of the risk profile for OSA is important. In this study, we sought to determine if OSA risk is similar in patients with generalized versus focal epilepsy.

METHODS

We recruited 115 patients presenting to the Rutgers-Robert Wood Johnson Epilepsy Clinic with focal or generalized epilepsy. Obstructive sleep apnea risk was assessed using the Sleep Apnea Scale of the Sleep Disorders Questionnaire (SA-SDQ). Sleepiness was assessed using the Epworth Sleepiness Scale (ESS). Demographic and clinical information was gathered from the electronic medical record. Unadjusted and adjusted analyses were carried out to assess differences in the SA-SDQ between patients with generalized versus focal epilepsy. Further analyses were done to assess the relationship between seizure frequency, epilepsy type, and the SA-SDQ.

RESULTS

Unadjusted mean SA-SDQ scores, as well as scores high enough to represent likely OSA, were similar in patients with generalized versus focal epilepsy. However, in adjusted analyses, patients with generalized epilepsy had a significantly higher mean SA-SDQ score. Older age, higher body mass index (BMI), and a history of hypertension (HTN) were also associated with higher SA-SDQ scores. Sleep Apnea Scale of the Sleep Disorders Questionnaire scores were not significantly affected by the presence of a seizure within the prior one month or six months. Average ESS scores and the percentage of scores consistent with an abnormal degree of sleepiness were statistically similar in patients with generalized versus focal epilepsy.

SIGNIFICANCE

Our study suggests that patients with generalized epilepsy have a higher risk of OSA. Further studies measuring OSA directly as well as assessing potential benefits of treatment are needed.

Rapid eye movement (REM) sleep and seizure control in idiopathic generalized epilepsy

BACKGROUND

Sleep and epilepsy are bedfellows, and they affect each other reciprocally. Despite the well-known relationship between sleep and epilepsy, data about the impact of sleep on seizure control and responsiveness to therapy are scarce.

OBJECTIVE

The aim of this work was to study the impact of sleep architecture in drug-naïve patients with idiopathic generalized epilepsy (IGE) on seizure control and responsiveness to treatment.

METHODS

This is a prospective cohort study conducted on thirty newly diagnosed patients with IGE attending the epilepsy clinic in Alexandria University Hospital in Egypt and thirty healthy controls. All recruited subjects had a baseline overnight polysomnographic study, then patients were given sodium valproate in therapeutic doses and followed up for six months for assessment of seizure control. After follow-up, they were classified into fully controlled and inadequately controlled patients, and a comparison between them was made.

RESULTS

Of the recruited patients, 13 were fully controlled. Rapid eye movement (REM) sleep % was significantly lower among inadequately controlled patients (9.01 ± 6.23) than fully controlled group (19.6 ± 9.01) and controls (18.17 ± 4.85) (p = 0.002), and the REM sleep latency was significantly longer among the inadequately controlled patients (115.7 ± 72.8 min) than fully controlled patients (54.6 ± 77.3 min) and controls (68.75 ± 37.95 min) (p = 011). On univariate regression analysis, the Odd's ratio (OR) for REM sleep percentage was 3.04 (p = 0.001).

CONCLUSION

Rapid eye movement sleep percentage and latency can contribute to seizure control in IGE.

Risk factors for drug-resistant epilepsy: A systematic review and meta-analysis

BACKGROUND

Drug resistant epilepsy (DRE) is very common among children and adults and studies had found some related risk factors for DRE, while the results were not consistent. The aim of this study was to identify risk factors for drug-resistant epilepsy.

METHODS

Three electronic databases (Medline, Embase and Cochrane library) were searched to identify studies with a cohort design reporting on epidemiologic evidence regarding risk factors for DRE.

RESULTS

The pooled prevalence of DRE in newly diagnosed epilepsy patients was 25% (95% CI 17-32%). Abnormal electroencephalography (EEG) (both slow wave and epileptiform discharges) (RR 2.80; 95% CI 1.95-4.0), status epilepticus (SE) (RR 11.60; 95% CI 7.39-18.22), symptomatic etiology (RR 3.36; 95% CI 2.53-4.46), multiple seizure types (RR 3.66; 95% CI 2.37-5.64) and febrile seizures (RR 3.43; 95% CI 1.95-6.02) were identified as strong risk factors for DRE. In addition, firm conclusions cannot be drawn for poor short-term outcomes of therapy, neurodevelopment delay and high initial seizure frequency for the heterogeneity of study results. The predictive effect of focus onset seizure was not stable after removing one study and switching the effect model. Age of onset was not risk factors for DRE.

CONCLUSIONS

The current meta-analysis identified potential risk factors for DRE. The results may contribute to better prevention strategies and treatments for DRE.

Nonconvulsive Seizure Detection by Reduced-Lead Electroencephalography in Children with Altered Mental Status in the Emergency Department

OBJECTIVES

To evaluate the proportion of children presenting to the emergency department (ED) with altered mental status who demonstrate nonconvulsive seizures on reduced-lead electroencephalography (EEG), and to further investigate the characteristics, treatment, and outcomes in these patients compared with patients without nonconvulsive seizures.

STUDY DESIGN

In this retrospective cohort study, we reviewed the database and medical records of pediatric patients (aged <18 years) in a single ED between May 1, 2016, and April 30, 2018. We first determined the proportion of nonconvulsive seizures among patients with altered mental status (Glasgow Coma Scale <15). We then compared the clinical presentation, demographic data, clinical diagnosis, EEG results, treatment, and outcomes of patients with altered mental status with nonconvulsive seizures and those without nonconvulsive seizures.

RESULTS

In total, 16.9% of the patients with altered mental status (41 of 242; 95% CI, 12.2%-21.6%) evaluated by EEG had detectable nonconvulsive seizure, equivalent to 4.4% (41 of 932) of all patients with altered mental status presenting at our hospital. More than 80% of patients monitored for nonconvulsive seizures had a previous history of seizures, often febrile. Patients with nonconvulsive seizures were older (median, 68.5 vs 36.1 months) and had a higher Pediatric Cerebral Performance Category score at presentation (median, 2.0 vs 1.0). In addition, the proportion of patients admitted to the intensive care unit was significantly higher in the patients with nonconvulsive seizures (30.3% vs 15.0%). However, total duration of hospitalization, neurologic sequelae, and 30-day mortality rate did not differ between the 2 groups.

CONCLUSIONS

A relatively high percentage of pediatric patients with altered mental status in the ED experience nonconvulsive seizures. The use of reduced-lead EEG monitoring in the ED might facilitate the recognition and treatment of nonconvulsive seizures, especially among patients with a history of seizures.

Clinical and genetic aspect of 30 tunisian families with febrile seizures

BACKGROUND

FS are the most benign occasional seizures in childhood. Little is known about the long term follow up.  Aim: To describe a long term follow-up of FS in Tunisian families.

METHODS

Field study was conducted for 30 patients with FS. We analyzed clinical phenotype of FS and associated afebrile seizures with genetic study.

RESULTS

We collected 107 individuals with febrile and / or afebrile seizures. Afebrile seizures were found in 28.3% of patients. The "FS" phenotype was found in 18 families (60%), "GEFS +" in 7 (23.33%), and idiopathic generalized epilepsy in 5 (16.66%). Sequencing analyses of SCN1A, SCN1B and GABRG2 genes revealed a novel SCN1B gene mutation in one family with FS and a known SCN1A mutation in GEFS+ family.

CONCLUSION

If FS are apparently isolated and infrequent, they occur most often in a family setting. The genetic studies remain difficult mainly because of the lack of phenotype-genotype correlation.

Predicting drug resistance in adult patients with generalized epilepsy: A case-control study

OBJECTIVES

Using an adult cohort of patients with generalized epilepsy, we aimed to identify risk factors for development of drug-resistant epilepsy (DRE), which if identifiable would allow patients to receive earlier treatment and more specifically individualized treatment plans.

METHODS

For the case-control study, 118 patients with generalized epilepsy (GE) between the ages of 18 and 75 were included after selection from a database of 800 patients referred from throughout the Saskatchewan Epilepsy Program. Definitions were used in accordance with ILAE criteria. The odds ratio and its confidence interval were calculated. We performed a logistic regression analysis.

RESULTS

Forty-four (37%) patients fulfilled the definition of DRE (cases), and seizures in 74 (63%) patients were not intractable (controls). Patients with DRE were significantly younger than the controls at the onset of epilepsy (6.6 vs. 18.8 years, p=<0.001). Significant variables on univariate analysis were the following: epilepsy diagnosed prior to 12 years (OR: 12.1, CI: 4.8-29.9, p<0.001), previous history of status epilepticus (OR: 15.1, CI: 3.2-70.9, p<0.001), developmental delay (OR: 12.6, CI: 4.9-32, p<0.001), and cryptogenic epilepsy (OR: 10.5, CI: 3.9-27.8, p<0.001). Our study showed some protective factors for DRE such as a good response to first AED, idiopathic etiology, and history of febrile seizures. In the logistic regression analysis, two variables remained statistically significant: developmental delay and more than one seizure type.

CONCLUSION

Our study has identified a set of variables that predict DRE in patients with generalized epilepsy. Risk factors identified in our study are similar to those previously identified in pediatric studies, however, our study is specifically tailored to adult patients with generalized epilepsy.

[Descriptive statistical analysis of the treatment of status epilepticus in a referral hospital]

INTRODUCTION

Status epilepticus is defined as either recurring seizures without regaining consciousness between them or one single seizure lasting more than 30 minutes.

AIMS

To perform a descriptive analysis of the most relevant data on the patients with status epilepticus who were admitted to a paediatric intensive care unit (PICU) and to review the risk factors associated to status epilepticus with a poor prognosis.

PATIENTS AND METHODS

A study was conducted of the main variables of the patients with status epilepticus hospitalised in the PICU of a tertiary hospital over a period of six years.

RESULTS

Data were collected on a total of 68 patients (55.9% males), the mean age being 3.7 years. The most frequent signs and symptoms were generalised tonic-clonic seizures (50%). The mean duration of the status epilepticus was 51.44 minutes. The mean number of antiepileptic drugs used to stem the seizures was 3.21 and the mean number of drugs used prior to admission to the PICU was 2.37. The most commonly used first choice drug was diazepam (83.8%) administered rectally (75%), followed by intravenous diazepam (52.9%) in second place and phenytoin was the most frequently used drug as the third choice. The most usual cause of status epilepticus was having previously suffered from epilepsy (33.9%), and Dravet's syndrome was the most frequent epileptic causation.

CONCLUSIONS

Treatment of status epilepticus is complex and requires multidisciplinary and personalised management. Protocols and clinical guidelines need to be drawn up and reviewed to achieve an adequate management of these patients.

[Long-term outcome and related factors of epileptic seizures in children]

OBJECTIVE

To analyze the Long-term outcome of seizures, and to explore the effects of related factors, including the age at onset, types of epileptic syndromes, and etiological factors, etc.

METHODS

The clinical data were retrospectively surveyed from 265 children with regular follow-ups for over 1 year at Peking University First Hospital (Jan. 2003 to Dec. 2006). The seizure-free rate was calculated as an at least one-year non-occurrence of seizures. The Long-term outcome of seizures was analyzed in association with factors including the age at onset, types of epileptic syndromes, and etiology.

RESULTS

(1) Seizure types were clarified in all the cases, with combined types of seizures in 17. Epileptic syndromes were identified in 163/265 cases (61.5%). With regular antiepileptic drug therapy, 57.9% children with epilepsy could be seizure-free. (2) Seizure-free was demonstrated in 142/265 cases with a seizure-free rate of 53.6% in this group. (3) The age at onset was youngest in the non-efficacy group. (4) The seizure-free rate was different by syndrome types of epilepsies, with a higher seizure-free rate in idiopathic generalized epilepsy (72.4%) and benign epilepsy in children with centro-temporal spikes (65.5%), whereas a lowest rate (21.7%) in infantile spasms. (5) A significant difference of seizure-free rates was revealed in different etiological groups. Children with idiopathic epilepsy achieved higher seizure-free rate (69.2%) than those with symptomatic and cryptogenic epilepsy (45.4%).

CONCLUSION

The epilepsy children with regular antiepileptic drug therapy had generally satisfactory outcome of seizures, with over half cases of seizure-free. The prognosis was demonstrated to be closely related with the etiological factors, syndrome types and age at onset.

[Aetiology and treatment of epilepsy in a series of 1,557 patients]

INTRODUCTION

The aetiology of epilepsy is an important decisive factor in its treatment and prognosis. Diagnostic and therapeutic advances suggest that the causal distribution, treatment and prognosis of the population with epilepsy may have undergone some modification.

AIM

To describe the distribution of syndromes, aetiology and pharmacological treatment in patients with epilepsy.

PATIENTS AND METHODS

We conducted a cross-sectional descriptive study of patients with epilepsy who were treated consecutively in our epilepsy department. Demographic data were collected, together with information about syndromes, aetiology and pharmacological treatment at the time of eligibility. The data were analysed jointly and by age groups.

RESULTS

Altogether 1,557 patients were included, 54% of them males. Seventy-three per cent of the sample had focal epilepsy, which was secondary to a structural lesion in 56% of patients. Generalised epilepsies accounted for 20%. Five per cent were unclassifiable. By ages, vascular causation predominated in practically all the groups and its prevalence increased with age. The most commonly used antiepileptic drugs were valproic acid (29%), levetiracetam (27%) and carbamazepine (20%). Seventy per cent of the generalised epilepsies and 57% of the focal ones were on monotherapy treatment.

CONCLUSIONS

The prevalence by age groups was similar to that reported in developed countries, although a lower prevalence of cryptogenic epilepsies was observed. More than 60% of patients followed monotherapy and valproic acid was the most widely used.

Focal clinical and electroencephalographic features in patients with juvenile myoclonic epilepsy

OBJECTIVE

To identify prevalence and factors associated with occurrence of focal clinical and electroencephalogram (EEG) abnormalities in patients with juvenile myoclonic epilepsy (JME).

MATERIALS AND METHODS

Clinical asymmetries in the seizures and focal EEG abnormalities were analyzed in 266 patients with JME.

RESULTS

All the patients had myoclonic jerks (MJ) and generalized tonic-clonic seizures (GTCS); 56 (21%) had absence seizures. Asymmetry in clinical seizures was reported in 45 (16.9%) and focal EEG abnormalities were noted in 92 (45.5%) patients. Amplitude asymmetry or focal onset of generalized discharges was noted in 41 (44.6%) and independent focal EEG abnormalities in 30 (32.6%) patients. A statistically significant association was seen with the presence of GTCS and MJ (P = 0.007), a family history of epilepsy (P = 0.001) and drug resistance (P = 0.04) and the occurrence of focal EEG abnormalities.

CONCLUSION

Patients with JME showed focal clinical and EEG features. These features should not be misinterpreted as indicative of partial epilepsy.

[Familial epilepsy]

BACKGROUND

Epilepsy is a chronic disease, with heterogeneous etiology, clinical spectrum and prognosis. Among many causes of epilepsy genetic factors and hereditary diseases with different inheritance mechanisms manifesting with epileptic seizures play an important role. Analysis of genealogy of families burdened with epilepsy, development of molecular and genetic tests may contribute to better understanding of mechanisms of epileptogenesis and more effective treatment of epilepsy.

AIM OF THE STUDY

Research and analysis of epilepsy incidence in families of children hospitalized because of epilepsy.

MATERIAL AND METHODS

The study included 18 children with diagnosed epilepsy and positive family history of epilepsy, hospitalized in the Department of Pediatric Neurology Chair of Pediatric and Adolescent Neurology in the years 2007-2009. Apart from thorough pregnancy and delivery history, brain imaging examinations (MR, CT) and inter seizure EEG recording were performed.

RESULTS

Positive family history of epilepsy was found in children at the age range from 1 month to 11 years. In the examined group predomination of older children (over 2 years of age) and girls (10/18) was observed. Epilepsy with generalized seizures was found in majority of patients from examined group. The siblings of the patients were the most often affected with the epilepsy.

CONCLUSIONS

Positive family history of epilepsy in children with epilepsy is almost always associated with occurrence of generalized seizures. Even in twins different types of seizures may occur, which may result from structural brain lesions in one of them. In research of familial occurrence of epilepsy repetitive history taking and complementation is needed.

Chronic intermittent vagal nerve stimulation in the treatment of refractory epilepsy: experience in Mexico with 35 cases

BACKGROUND

The role of vagal nerve stimulation (VNS) in the treatment of refractory epilepsy is still evolving and requires precision through extensive description of acute and chronic results, adverse effects and complications in specific populations.

METHODS

We selected patients with refractory epilepsy subjected to VNS who had completed at least a 12-month followup. Descriptive and inferential statistics were used to review and assess the effects of VNS on seizure frequency/intensity, memory, alertness, mood, postictal recovery, and quality of life (subjective scale, QoL IE-31 inventory) as well as factors (gender, age, age of onset, time of surgery, stimulation parameters, seizure frequency and type) associated with clinical response. We describe stimulation parameters, complications and adverse effects compared to other series.

RESULTS

We selected 35 patients with an age range of 5-48 years; 18 patients presented partial epilepsy and 17 generalized epilepsy. All procedures and wound healing were uneventful, and no infections were reported. Median reduction in seizure frequency was 55.65% (p <0.001). Four patients showed improvement of >90%. Two patients became seizure free, whereas seizure frequency increased in two patients. The subjectively qualified response to treatment was good in 33 patients. The mean global increase in the QoLIE-31 Scale was 12.6 (p = 0.020). Improvements in memory, mood, alertness and postictal recovery period were documented. Only seizure type showed statistically significant association with clinical response. Adverse effects were transitory and responded to changes in stimulation parameters.

CONCLUSIONS

VNS is a safe, feasible, well-tolerated and effective palliative treatment in appropriately selected cases of refractory partial and multifocal generalized seizures.

[Photosensitivity and generalized idiopathic epilepsies of children]

The aim of this study is to evaluate the frequency of photosensitivity at patients of paediatric age diagnosed with different types of generalized idiophatic epilepsies.

MATERIAL AND METHOD

We used a group of 68 children aged 3-18 years diagnosed: 39 patients with childhood absence epilepsy (CAE), 11 with juvenile absence epilepsy (JAE), 10 with epilepsy with grand mal on awakening (EGMA), 8 with juvenile myoclonic epilepsy (JME). EEG was recording without and with stimulation (hyperventilation, intermittent photic stimulation -IPS) after sleep deprivation. For all children with CAE absences and anormal EEG was provoked by hyperventilation and in 12 cases seizures was provoked by IPS.

RESULTS

At 4 patients with JAE, EEG show photosensitivity. 5 children with JME have photosensitivity and for one child opening eyes provoked polyspike-wave discharges without clinical correspondent. The EEG of patients with EGMA showed photosensitivity at 6 children. The photosensitivity is frequently associated with generalized idiophatic epilepsies (32.35%) and it is most often seen at girls (54.54%) of puberty age.

Post stroke seizures: descriptive study from a tertiary care centre in Pakistan

OBJECTIVE

To determine the frequency, mode of onset and outcome of post stroke seizures in a local setting.

METHODS

The retrospective (Aug 1999 to July 2001) and prospective (August 2001 to July 2002) data of patients aged 14 years and above, with post stroke seizures was collected from a tertiary care centre in a metropolitan city. The demographic, clinical, radiological, laboratory, neurophysiologic and outcome data was recorded and analyzed.

RESULTS

During the three year period 1548 patients with stroke were admitted to the hospital. Four hundred thirty one (28%) had intracerebral haemorrhage (ICH) and 1117 (72%) had ischaemic stroke. One hundred seventeen (8%) of the 1548 had seizures. Their mean age was 63 +/- 12 (range; 15-70) years. Fifty-nine (50%) were men and 58 (50%) were women. Twenty of 431(5%) patients with ICH and 97/1117 (9%) with ischaemic stroke, developed seizures. Nine of 117 (8%) developed a seizure within 14 days of stroke and 108/117 (92%) developed seizures after 14 days of stroke. Twenty-six (22%) had partial and 91 (78%) had generalized seizures. Two patients expired early in the course. Twenty four (21%) of these continued to have seizures at one year follow up. Fifteen of 37 (40%) patients who had systemic infections early in the course continued to have seizures at one year as compared to 9/80 (11%) who did not (p = 0.001).

CONCLUSIONS

Frequency of post stroke seizures is the same as reported in western literature. Post stroke seizures are more common in patients with ischaemic stroke. Generalized seizures are more common than partial seizures. Systemic infections early in the course are associated with recurrence of seizures at one year.

Idiopathic Generalized Epilepsy with Absences: Syndrome Classification

In a cohort of 275 Caucasians with a broad IGE phenotype, patients with absences were classified. Criteria of the 1989 Commission on Classification of the International League Against Epilepsy for Childhood Absence Epilepsy (CAE 1989 criteria) were compared with the stricter criteria of the ILAE Task Force for Classification and Terminology (CAE 2005 criteria). Among the 129 patients with absences without significant myoclonus, 50 had juvenile absence epilepsy 44 had CAE according to the CAE 1989 criteria and only 30 had CAE according to the CAE 2005 criteria. We found a significantly better outcome in patients considered as CAE by the CAE 2005 criteria, compared with those excluded. Strict criteria for classification of absence syndromes leave many patients unclassified. However, diagnostic criteria used to classify CAE patients have prognostic significance. We propose that patients are classified as having benign CAE or as having CAE with the adverse prognostic factors indicated.

Familial generalized epilepsy in Bulgarian Roma

AIMS

Gypsy communities constitute cultural and frequently inbred genetic isolates. Several genetic neurological disorders have been identified in these communities. Epilepsy appears as a fairly frequent medical condition among Bulgarian Gypsies, and many patients can be related to large pedigrees that may then be studied by conventional genetic linkage analyses.

PATIENTS AND METHODS

We identified two large Wallachian Gypsy families from the Plovdiv and Varna regions of Bulgaria, with detailed clinical questionnaires and examination, and EEG recordings for many. Genetic linkage analysis was performed using microsatellite markers spaced across the human genome.

RESULTS

Although phenotypes were not always easy to identify, epilepsy appears in both families as a dominant, or pseudo-dominant trait, with the characteristics of idiopathic generalized epilepsy with onset at various ages, with infrequent, generalized tonic-clonic seizures, some associated with fever in childhood, but without sensitivity to fever in later life. While few markers yielded LOD scores > 2, no locus showed significant linkage, assuming autosomal dominant or recessive modes of inheritance.

CONCLUSION

Idiopathic generalized epilepsy, with a marked familial character, has not been reported to date in Bulgarian Gypsies. Both pedigrees studied here present with an identifiable epilepsy type inherited as a Mendelian trait. Despite the current lack of significant linkage, these families may constitute interesting ground for further genetic studies, on condition that more patients and families can be recruited. [Published with supplemental data on DVD].

Long-term Prognosis for Symptomatic (Secondarily) Generalized Epilepsies: A Population-based Study

PURPOSE

To describe the long-term outcome of childhood-onset secondarily generalized epilepsies (SGEs).

METHODS

Children were identified from the Nova Scotia population-based epilepsy study (n=692). Onset of epilepsy was between 1977 and 1985, and follow-up was mainly in 2003. SGE was defined as having a mixture of more than one generalized seizure types including myoclonus, akinetic/atonic, tonic, or atypical absence, plus an interictal EEG with generalized spike-wave (irregular or slow) and/or multifocal spikes.

RESULTS

SGE was identified in 80 children, 11.6% (80 of 692) of all childhood epilepsy. Forty percent did not fit into a currently accepted syndrome (such as Lennox-Gastaut, myoclonic-astatic or West). Seizure onset was in the first year of life in 60%, with only 9% later free of intellectual or physical handicap. Sixty-five percent (11 of 17) with Lennox-Gastaut had preceding West syndrome. During a median follow-up of 20 years, mortality was 24% (n=19), and 53% (n=42) had persistently intractable seizures. Surprisingly, 22 (28%) had >or=5 years of terminal remission (West, 31%, 10 of 32; Lennox-Gastaut, 0, none of four; myoclonic-astatic, 56%, five of nine; undefined, 31%, 10 of 32). At the end of follow-up, nearly 90% of patients fell into one of three outcome categories: death, 19 (24%); alive with intractable epilepsy, 31 (39%); or in remission for >or=5 years, 21 (26%).

CONCLUSIONS

Many children with SGE have ill-defined epilepsy syndromes. SGE is characterized by early age at onset, high rates of handicap, intractability, and death, although one third achieve complete seizure control with a long terminal remission.

Executive functioning in childhood epilepsy: parent-report and cognitive assessment

There is considerable interest in the assessment of executive function (EF) in pediatric clinical populations but only a few well-standardized measures exist. We examined EF in 53 children aged 8 to 18 years with recent onset epilepsy (31 males, 22 females) and 50 control children (23 males, 27 females) using the Behavior Rating Inventory of Executive Function (BRIEF) and the Delis-Kaplan Executive Function System (D-KEFS). Thirty children had localization-related epilepsy and 23 had idiopathic generalized epilepsy; average duration of 10 months (SD 4y 1mo) and onset age of 11 years 6 months (SD 3y 6mo). The study sample was characterized by good seizure control, with 40 participants taking one antiepileptic drug (AED), one taking two AEDs, and 12 not treated pharmacologically. Children with epilepsy showed greater executive difficulties on both measures than children in the control group. The BRIEF and D-KEFS were significantly correlated, and an 'at-risk' group identified from the BRIEF was more significantly impaired on the D-KEFS than a 'low risk' group. The BRIEF was also a better predictor of performance on the D-KEFS than the Child Behavior Checklist. These findings indicate that children with recent onset epilepsy show significant difficulties in E F, and demonstrate the utility of parent ratings (BRIEF) in the assessment of EF.

"Tonic-absence seizures": an unusual seizure phenotype, but not necessarily in that order

Video telemetry in a 15-year-old boy with moderate learning difficulties revealed episodes of staring and cessation of activity, followed by sudden stiffening of the body for several seconds, abduction of the arms and a brief vocal utterance ("ugh"). Each episode lasts around 30 seconds, 3-4 times/day despite treatment. The EEG showed generalized 3-4Hz spike-wave discharges during the "absence" period followed immediately by a run of fast polyspikes typical of a tonic seizure, terminating in a run of 1-2 Hz sharp-slow wave complexes. Although tonic-absence seizures have been reported rarely, the clinical sequence appears to be reversed in this patient, with the occurrence of "absence-tonic" attacks. We present video documentation of such attacks and discuss their nosology.[Published with video sequences].

A study of idiopathic generalised epilepsy in an Irish population

Idiopathic generalised epilepsy (IGE) is subdivided into syndromes based on clinical and EEG features.

PURPOSE

The aim of this study was to characterise all cases of IGE with supportive EEG abnormalities in terms of gender differences, seizure types reported, IGE syndromes, family history of epilepsy and EEG findings. We also calculated the limited duration prevalence of IGE in our cohort.

METHODS

Data on abnormal EEGs were collected retrospectively from two EEG databases at two tertiary referral centres for neurology. Clinical information was obtained from EEG request forms, standardised EEG questionnaires and medical notes of patients.

RESULTS

two hundred twenty-three patients met our inclusion criteria, 89 (39.9%) male and 134 (60.1%) females. Tonic clonic seizures were the most common seizure type reported, 162 (72.65%) having a generalised tonic clonic seizure (GTCS) at some time. IGE with GTCS only (EGTCSA) was the most common syndrome in our cohort being present in 94 patients (34 male, 60 female), with 42 (15 male, 27 female) patients diagnosed with Juvenile myoclonic epilepsy (JME), 23 (9 male, 14 female) with Juvenile absence epilepsy (JAE) and 20 (9 male, 11 female) with childhood absence epilepsy (CAE). EEG studies in all patients showed generalised epileptiform activity.

CONCLUSIONS

More women than men were diagnosed with generalised epilepsy. Tonic clonic seizures were the most common seizure type reported. EGTCSA was the most frequent syndrome seen. Gender differences were evident for JAE and JME as previously reported and for EGTCSA, which was not reported to date, and reached statistical significance for EGTCA and JME.

Auras are frequent in idiopathic generalized epilepsy

The occurrence of an aura is often considered evidence of a partial rather than an idiopathic generalized epilepsy syndrome. The authors examined this hypothesis by prospectively recording reports of auras by patients being admitted for video-EEG monitoring. Auras were equally common (70%) among patients with idiopathic generalized epilepsy as they were among those with localization-related epilepsy. Presence of an aura is not a reliable indicator of localization-related epilepsy.

Prevalence of Epilepsy in a Rural District of Central Lao PDR

PURPOSE

To assess the prevalence of epilepsy in a rural district of Lao PDR and to describe the clinical and epidemiological profile of the disease.

METHODS

Door-to-door screening was performed on the entire population of 8 randomly selected villages in the Hinheub district, using an internationally validated and standardized questionnaire. Additional passive case detection was performed through village key informants. Suspected epilepsy patients identified by the questionnaire were revisited and examined by an experienced neurologist on two follow-up visits. The confirmation of epilepsy was based only on an in-depth clinical examination. Electroencephalograms were performed at the district health care center.

RESULTS

In the 8 villages, 277 suspected cases of epilepsy were identified among 4,310 interviewed subjects; 194 of whom (70%) underwent a clinical examination by a neurologist during the first visit while 65 of 83 remaining suspected cases were seen on the second confirmation visit. Twenty-seven persons with epilepsy were identified. Six additional patients were diagnosed in 219 self-referred subjects. An overall prevalence of 7.7 cases of epilepsy per thousand inhabitants was calculated (95% CI 5.3-10.7). Generalized epilepsy (21 cases, 63.6%) was commoner than partial epilepsy (9 cases, 27.3%). The remaining 3 cases (9.1%) were not-classifiable as either generalized or partial. EEG abnormal findings were found in 12 of the 24 patients (50.0%) who had an EEG registration.

CONCLUSIONS

This is the first study in Lao PDR to estimate the prevalence of epilepsy. Compared to Western countries it shows a pattern towards a higher prevalence.

Language-induced Epilepsy, Acquired Stuttering, and Idiopathic Generalized Epilepsy: Phenotypic Study of One Family

PURPOSE

Language-induced epilepsy involves seizure precipitation by speaking, reading, and writing. Seizures are similar to those of reading epilepsy (RE). The nosologic position of language-induced epilepsy is not clear. We performed a clinical and neurophysiological study in a multigenerational family with the association of idiopathic generalized epilepsy (IGE) with ictal stuttering as a manifestation of reflex language-induced epilepsy.

METHODS

Nine members on three generations were studied. All patients underwent video-polygraphic EEG recordings (awake and during sleep). A standardized protocol was applied to test the effect of language and non-language-related tasks.

RESULTS

Six patients presented language-induced jaw jerking that mimicked stuttering and corresponded to focal myoclonus involving facial muscles. This was associated with an IGE phenotype in four of these patients. Focal EEG spikes were found in all six patients by visual analysis and/or back-averaging techniques. The focal spikes were either asymptomatic (when followed by a slow wave) or symptomatic of facial myoclonia (when isolated). Levetiracetam, used as add-on or monotherapy in four patients, suppressed ictal stuttering. One additional case only had a phenotype of IGE without focal features.

CONCLUSIONS

This family study demonstrates the phenotypic heterogeneity of the association of IGE phenotype with ictal stuttering (language-related reflex seizure). Our data suggest that this particular form of reflex epilepsy related to language has more similarities with generalized epilepsies than with focal ones. Neurophysiological investigations should be performed more systematically in patients with acquired stuttering, especially if there is family history of IGE.

Epilepsy and obstructive sleep apnea

A few publications documented the coexistence of epilepsy and obstructive sleep apnea (OSA). The extent, nature, and clinical relevance of this association remain poorly understood. We retrospectively reviewed the database of our sleep center to identify patients with both sleep apnea and epilepsy. Characteristics of epilepsy, sleep history, presence of excessive daytime sleepiness [Epworth Sleepiness Scale (ESS)] and polysomnographic data were assessed. The effect of continuous positive airway pressure (CPAP) on seizure reduction was prospectively analyzed after a median interval of 26 months (range: 2-116 months) from the diagnosis of OSA. OSA was found in 29 epilepsy patients (25 men and 4 women) with a median age of 56 years (range: 37-79). The median apnea hypopnea index was 33 (range: 10-85), the oxygen desaturation index was 12 (range 0-92), and 52% of the patients had an ESS score >10. In 27 patients, epilepsy appeared 1 month to 44 years prior to the diagnosis of OSA. In 21 patients, the appearance of OSA symptoms coincided with a clear increase in seizure frequency or the first appearance of a status epilepticus. Treatment with CPAP was continued with good compliance in 12 patients and led to a significant reduction of both ESS scores and seizure frequency in 4 patients. Our data suggest the importance of considering diagnosis and treatment of OSA in epilepsy patients with poor seizure control and/or reappearance of seizures after a seizure-free interval.

Prevalence of Childhood Epilepsy and Distribution of Epileptic Syndromes: A Population-based Survey in Okayama, Japan

PURPOSE

A population-based survey childhood epilepsy was undertaken in Okayama Prefecture, Japan, to determine the prevalence rate and the distribution of epilepsies and epileptic syndromes according to the International Classification (ILAE, 1989).

METHODS

Information on patients younger than 13 years with active epilepsy was collected from medical records. Patients diagnosed with epilepsy according to clinical and EEG findings were put on the list even if those patients had had a single seizure or seizures occurring during febrile episodes.

RESULTS

In total, 2,220 cases were identified from a background population of 250,997. The prevalence rate was 8.8 per 1,000. If we exclude patients who had experienced a single seizure or seizures occurring during febrile episodes to compare our results with previous reports, the prevalence rate was 5.3 per 1,000. Of the 2,220 cases, 2,030 (91.4%) were classified into three major categories by ILAE classification. They consisted of 1,556 (76.7%) with localization-related epilepsy, 453 (22.3%) with generalized epilepsy, and 21 (1.0%) with undetermined epilepsy. Of the 2,030 cases, 309 (15.2%) were classified into epileptic syndrome categories, and 84.8% of the total were nonspecific types of epilepsy.

CONCLUSIONS

The prevalence rate of childhood epilepsy was distributed from 5.3 to 8.8 per 1,000. The appearance rate of various types of epileptic syndromes was low. Most cases could not be classified into the detailed categories of the International Classification (ILAE, 1989).

Clinical and electroencephalographic study of first-degree relatives and probands with juvenile myoclonic epilepsy

PURPOSE

Juvenile myoclonic epilepsy (JME) is a common, well-defined epileptic syndrome. This study aims to examine the clinical and EEG features of probands with JME and to identify the incidence of different types of idiopathic generalized epilepsies (IGEs) and IGE trait in first-degree relatives.

METHODS

Clinical and EEG data were collected from 132 first-degree relatives and 31 probands with JME. The data were analyzed using descriptive statistics, chi-square test, t-test and ANOVA.

RESULTS

All probands had a history of generalized tonic clonic seizures (GTCS) and myoclonic jerks; 25.8% had a history of absence seizures. Family history of epilepsy was noted in 42% and epilepsy in first-degree relatives was reported in 38.7%. We found JME in 44% of the symptomatic first-degree relatives. The incidence of epilepsy was higher in siblings (19%) than in offspring (8%) or parents (4%), the difference between the groups being significant (p < 0.05). IGE trait was noted in 6% of the asymptomatic first-degree relatives. Finally, IGE features were found in 61%. Subjects with IGE features were younger (mean age 19.6 years) than those without IGE features (mean age 32.4 years) and the difference between the groups was significant.

CONCLUSION

The incidence of different kinds of IGEs and typical EEG trait is high in first-degree relatives of JME probands. IGE features were noted in 61% of the families. JME is the most common type of IGE and IGE features were found to be more frequent among siblings than parents. These findings confirm familial susceptibility to IGE.

Prevalence of active epilepsy in a rural area in South Tanzania: a door-to-door survey

OBJECTIVE

A door-to-door survey was carried out to assess the prevalence of active epilepsy in the rural population within the catchment area of the Mnero Diocesan Hospital in Southern Tanzania.

METHODS

A total of 4,905 individuals living in 1,047 households were enrolled in a study, consisting of a screening dialogue with a representative family member followed by a face-to-face interview with the affected subject. The diagnosis of epilepsy followed clinical guidelines proposed by the International League Against Epilepsy (ILAE).

RESULTS

We detected 42 cases (21 males and 21 females) of active epilepsy (8.6/1,000; 95% CI: 6.0/1,000-11.1/1,000; age-adjusted prevalence ratio: 7.4/1,000). Thirty of them met the case definitions of generalized seizures, whereas 12 patients reported partial seizures. The peak prevalence was found in both sexes in the second decade of life (f: 16.9/1,000; m: 15.8/1,000; t: 16.4/1,000), with a second peak in the group aged 30-39 years (f: 10.4/1,000; m: 8.8/1,000; t: 9.7/1,000). Eleven patients (26.2%) were classified as "strongly suspected of symptomatic" epilepsy, the remaining 31 patients (73.8%) as possibly being idiopathic, symptomatic, or cryptogenic epilepsy cases.

DISCUSSION

This study provides baseline data about the active epilepsy prevalence in a rural African population. Compared to western countries, our study confirmed a pattern toward higher prevalence of epilepsy in tropical countries. As shown in previous studies, we observed a higher prevalence of epilepsy in children and adolescents, followed by a steady decline with increasing age. Reasons for this type of frequency could be ascribed to malnutrition, trauma, genetic conditions, antenatal and prenatal care, diseases resulting in febrile convulsions, cerebral infections and may even result in death in specifically diseased individuals.

Familial clustering of seizure types within the idiopathic generalized epilepsies

OBJECTIVE

To examine the genetic relationships among epilepsies with different seizure types--myoclonic, absence, and generalized tonic-clonic--within the idiopathic generalized epilepsies (IGEs).

BACKGROUND

Careful phenotype definition in the epilepsies may allow division into groups that share susceptibility genes. Examination of seizure type, a phenotypic characteristic less complex than IGE syndrome, may help to define more homogeneous subgroups.

METHODS

Using the approach that found evidence of distinct genetic effects on myoclonic vs absence seizures in families from the Epilepsy Family Study of Columbia University, the authors examined an independent sample of families from Australia and Israel. They also examined the familial clustering of generalized tonic-clonic seizures (GTCs) within the IGEs in two combined data sets. Families were defined as concordant if all affected members had the same type of seizure or IGE syndrome, as appropriate for the analysis performed.

RESULTS

The proportion of families concordant for myoclonic vs absence seizures was greater than expected by chance in the Australian families. In addition, GTCs clustered in families with IGEs to a degree greater than expected by chance.

CONCLUSIONS

These results provide additional evidence for distinct genetic effects on myoclonic vs absence seizures in an independent set of families and suggest that there is a genetic influence on the occurrence of generalized tonic-clonic seizures within the idiopathic generalized epilepsies.

A case of extended spectrum GEFS+

A 10-year-old boy developed febrile convulsions at age 2 years, and multiple types of nonfebrile generalized seizures over the ensuing months and years. Gestation, birth, and early development were normal, as were initial EEG and brain imaging studies. By age 5 years, he had developed behavioral difficulties, and the EEG demonstrated both interictal and ictal generalized epileptiform patterns, as well as mild background slowing. Seizures were poorly controlled with multiple medication trials. There was a strong family history of clinically benign febrile seizures in the maternal lineage. Genetic analysis revealed a novel mutation in the voltage-gated neuronal sodium channel SCN1A. This patient's relatively malignant clinical course is consistent with "extended spectrum" generalized epilepsy with febrile seizures plus (GEFS+), and along with the family history illustrates the phenotypic variability of this disease.

Neonatal epilepsy syndromes and GEFS+: mechanistic considerations

Genetic analyses of familial epilepsies over the past decade have identified mutations in several different ion channel genes that result in neonatal or early-onset seizure disorders, including benign familial neonatal convulsions (BFNC), generalized epilepsy with febrile seizures plus (GEFS+), and severe myoclonic epilepsy of infancy (SMEI). These genes encode voltage-gated Na+ channel subunits (SCN1A, SCN2A, SCN1B), voltage-gated K+ channel subunits (KCNQ2, KCNQ3), and a ligand-gated neurotransmitter receptor subunit (GABRG2). While the opportunity to genotype patients for mutations in these genes can have an immediate and significant impact on our ability to diagnose and provide genetic counseling to patients, the ultimate goal is to use this molecular knowledge to develop effective treatments and cures for each disorder. This will necessitate elucidation of the molecular, cellular, and network mechanisms that translate ion channel defects into specific epilepsy phenotypes. The functional analysis of epileptogenic channel mutations in vitro and in vivo has already provided a vast amount of raw biophysical data, but attempts to interpret these data to explain clinical phenotypes so far appear to raise as many questions as they answer. Nevertheless, patterns are beginning to emerge from these early studies that will help define the full scope of the challenges ahead while simultaneously providing the foundation of future efforts to overcome them. Here, I discuss some of the potential mechanisms that have been uncovered recently linking mutant ion channel genes to neonatal epilepsy syndromes and GEFS+.

Seizures of idiopathic generalized epilepsies

Idiopathic generalized epilepsies (IGEs) comprise at least 40% of epilepsies in the United States, 20% in Mexico, and 8% in Central America. Here, we review seizure phenotypes across IGE syndromes, their response to treatment and advances in molecular genetics that influence nosology. Our review included the Medline database from 1945 to 2005 and our prospectively collected Genetic Epilepsy Studies (GENESS) Consortium database. Generalized seizures occur with different and similar semiologies, frequencies, and patterns, ages at onset, and outcomes in different IGEs, suggesting common neuroanatomical pathways for seizure phenotypes. However, the same seizure phenotypes respond differently to the same treatments in different IGEs, suggesting different molecular defects across syndromes. De novo mutations in SCN1A in sporadic Dravet syndrome and germline mutations in SCN1A, SCN1B, and SCN2A in generalized epilepsies with febrile seizures plus have unraveled the heterogenous myoclonic epilepsies of infancy and early childhood. Mutations in GABRA1, GABRG2, and GABRB3 are associated with absence seizures, while mutations in CLCN2 and myoclonin/EFHC1 substantiate juvenile myoclonic epilepsy as a clinical entity. Refined understanding of seizure phenotypes, their semiology, frequencies, and patterns together with the identification of molecular lesions in IGEs continue to accelerate the development of molecular epileptology.

Syndromes of idiopathic generalized epilepsies not recognized by the International League Against Epilepsy

This chapter assesses probable epileptic syndromes within the idiopathic generalized epilepsies (IGE) that have not yet been recognized by the International League Against Epilepsy (ILAE). Jeavons syndrome, a purely reflex IGE that predominantly manifests with eyelid myoclonia and electroencephalogram (EEG) abnormalities on eye closure, is the most distinct and undisputed of the syndromes. Another is autosomal-dominant cortical tremor, myoclonus, and epilepsy, a purely monogenic disorder that has been documented in numerous reports, mainly from Japan and Italy. Perioral myclonia with absences is certainly a seizure type that may constitute an IGE syndrome when it is associated with a number of other clinical and EEG manifestations. Similarly, many patients suffer for years from phantom absences, a type of mild absence, before a first generalized tonic-clonic seizure that usually occurs in adulthood. Both perioral myoclonia with absences and phantom absences are clinically significant because they are probably lifelong and are associated with a very high incidence (around 50%) of absence status epilepticus that may escape diagnosis and appropriate treatment. The position of early childhood IGE, which manifests mainly with typical absence seizures that are distinctly different from childhood absence epilepsy and other recognized IGE syndromes, is less clear. The prevalence of these syndromes is significant. Their identification allows better clinical management and is important for genetic research and counselling. In addition, their recognition permits application of exclusion criteria for a more purified definition and a better understanding of the true boundaries of the other IGE syndromes already accepted by the ILAE.

Epidemiology of idiopathic generalized epilepsies

Idiopathic generalized epilepsies (IGEs) are a relatively new category of disorders defined by strict clinical and electroencephalogram (EEG) features proposed by the International League Against Epilepsy (ILAE) classification of epileptic syndromes. IGEs are usually easy to diagnose when clinical and EEG data are collected, but epilepsy is not synonymous with epileptic syndrome. So far, IGEs are studied in the large group of epilepsies of undetermined or unknown etiology although the genetic origin is now largely accepted. ILAE-proposed criteria are helpful in the clinical and therapeutic management of IGEs, but many epidemiologic studies still confuse the cryptogenic and idiopathic groups. Some syndromes in childhood, which are completely described by strict electroclinical criteria such as the absence epilepsies, juvenile myoclonic epilepsies, are usually included and analyzed in epidemiologic studies; however, other epileptic syndromes observed in infancy, such as benign familial neonatal seizures and benign myoclonic epilepsy in infancy, are quite rare and are usually excluded from epidemiologic surveys because they are difficult to describe completely in electro-clinical terms. Another strong limitation in the study of epidemiology of IGEs is the lack of EEG data, either because EEG is not available or the routine EEG is normal. This is particularly relevant in the inclusion of patients with only tonic-clonic seizures. IGEs encompass several different syndromes, and a few patients shift from one phenotype to another. The overlapping of some syndromes during infancy and adolescence increased the difficulty to individualize strictly the correct syndrome. Many discrepancies can be observed in the distribution of the different syndromes included in the group of IGEs, because the strict criteria for classifying these syndromes proposed by the ILAE are often not respected. With this understanding, the general frequency of IGEs can be assessed at 15-20% of all epilepsies. The frequency and the distribution of incidence and prevalence of the different syndromes are tentatively reported and discussed. When the term idiopathic is used following the restrictive ILAE criteria, the mortality data concerning patients with idiopathic epilepsies do not show an increased standardized mortality ratio.

Nonepileptic disorders imitating generalized idiopathic epilepsies

Differential diagnosis between epileptic and nonepileptic paroxysmal disorders is fundamental not only to allow correct management of patients but also to avoid the burden of unnecessary antiepileptic medication. The focus of this chapter is limited to imitators of idiopathic generalized epilepsies (IGE) which are expressed through myoclonic, tonic-clonic, tonic, atonic, and absence seizures. Apparent losses of consciousness and drop attacks also have to be considered. Benign myoclonus of early infancy is the main nonepileptic disorder in the differential diagnosis of infantile spasms, but is not dealt with here because West syndrome is not an IGE. Hyperekplexia, metabolic disorders, hypnagogic myoclonus, and disturbed responsiveness caused by the use of drugs are listed in Table 1. Other conditions that may imitate more focal epileptic seizures are omitted. Benign neonatal sleep myoclonus, apnea and apparent life-threatening events in infants, cyanotic and pallid breath-holding spells, syncope, staring spells, psychogenic seizures, hyperventilation syndrome, and narcolepsy have been selected based on frequency or difficulties in differential diagnosis with the intention to cover the most conspicuous imitators of IGE in different ages.

Photosensitivity in Idiopathic Generalized Epilepsies

Photosensitivity is an abnormal visual sensitivity of the brain in reaction to flickering light sources or patterns and is expressed in the electroencephalogram as generalized spike-and-wave discharge and in more susceptible individuals as clinical seizures. The most common types of seizures are generalized tonic-clonic, followed by myoclonic and absence. The photosensitive epilepsies are classified as pure photosensitive, where seizures occur only with the flickering light source/pattern or during intermittent photic stimulation (IPS) in the laboratory, and epilepsy with photosensitivity, where spontaneous seizures also occur. Positive response to IPS in idiopathic epilepsy syndromes, which are included in the International Classification or are in development, is reported to range from 7.5% in juvenile absence epilepsy to 100% in pure photosensitive epilepsy. The treatment of photosensitivity and pure photosensitive epilepsy with rare seizures includes general and specific protective measures. For most patients, however, combination treatment with antiepileptic drugs is necessary. Valproic acid monotherapy has a success rate of 73-86%. Levetiracetam appears to be a new alternative therapeutic option. Clobazam, lamotrigine, ethosuximide, and topiramate also have been recommended as second-choice therapies.

Status Epilepticus in Idiopathic Generalized Epilepsy

Status epilepticus (SE) can take various forms in idiopathic generalized epilepsy (IGE), some of which forms also occur in symptomatic or focal epilepsies. Although the clinical semiology of the SE episodes may be similar in these different epilepsies, the frequency, response to treatment and prognosis differ. (a) Convulsive SE is surprisingly uncommon in IGE and much less common than in the secondarily generalized or partial epilepsies. Also, when it does occur, it usually responds rapidly to treatment. (b) Typical absence SE occurs only in patients with IGE (the subcategories with typical absence seizures) and also in the syndrome of de novo absence SE of late onset. This form of nonconvulsive SE should be differentiated from atypical absence SE, which occurs in the secondarily generalized epilepsy encephalopathies, and from complex partial SE which occurs in focal epilepsy. The clinical symptoms of these three types overlap but the prognosis and response to treatment are different. The mechanisms underlying absence SE are uncertain and may include both genetic and environmental factors. The termination of absence seizures has been hypothesized to be due to persistent activation of a depolarizing current in thalamocortical neurons that inactivates T-type calcium channels. SE could thus result from dysfunction of this channel or mechanisms that hyperpolarize thalamocortical neurons-these include decreased cortical inhibition, increased reticular thalamic neuronal activity or increased thalamocortical neuron GABA(B)-receptor activation. (c) Generalized electrographic SE is encountered in IGE in the syndrome of phantom absence with GTCS. It also occurs in ESES and in the Landau-Kleffner syndrome. The seizure phenomenology overlaps with the focal SE of temporal or frontal lobe epilepsy. (d) Myoclonic SE is also uncommon in IGE but occurs in juvenile myoclonic epilepsy. It is more commonly encountered in progressive myoclonic epilepsies, myoclonic-astatic epilepsy and in the Dravet syndrome. (e) Autonomic status occurs largely in the Panayiotopoulos syndrome. It is included here under the rubric of IGE, although the epilepsy has focal as well as generalized features and its nosological position is controversial. Fifty percent of seizures in this syndrome could be classified as status epilepticus. There is no doubt that convulsive SE can result in cerebral damage. In animal models of focal SE, nonconvulsive forms can also result in cerebral damage, but cerebral damage is not observed in animal models of absence SE. Similarly, cerebral damage seems not to occur in the forms of nonconvulsive SE in human IGE.