Genetic liability to epilepsy in Kerala State, India

Prevalence, incidence, and risk factors of epilepsy in arab countries: A systematic review

OBJECTIVE

To describe the prevalence, incidence, and risk factors of epilepsy in Arab countries.

METHODS

In this systematic review, electronic databases including PubMed, ProQuest Public Health and Cochrane Library were searched to identify relevant English articles published until April 2020. The search was conducted to cover all 22 Arab countries. Studies were eligible for inclusion if they assessed any of these epidemiological parameters of epilepsy: prevalence, incidence, and/or risk factors and focused on at least one of the Arab countries. The quality of the studies was evaluated using standardized quality assessment tools.

RESULTS

Twenty-nine articles met the inclusion criteria. Out of the 22 Arab countries, only 11 were found to have published studies reporting on the epidemiology of epilepsy. The median lifetime prevalence of epilepsy in Arab countries was found to be 6.9 per 1000. The median incidence is 89.5 per 100000. The most frequently identified risk factors were parental consanguinity, family history of epilepsy, and a history of perinatal infections/insults.

CONCLUSION

The prevalence and incidence of epilepsy varies in Arab countries. The most frequently reported risk factor is parental consanguinity. The lack of epidemiological studies on epilepsy in half of the Arab countries calls for more studies on this aspect to identify the burden and risk factors of epilepsy in this region.

An overview of structurally diversified anticonvulsant agents

There are several limited approaches to treat epilepsy in hospitals, for example, using medicines, surgery, electrical stimulation and dietary interventions. Despite the availability of all these new and old approaches, seizure is particularly difficult to manage. The quest for new antiepileptic molecules with more specificity and less CNS toxicity continues for medicinal chemists until a new and ideal drug arrives. This review covers new antiseizure molecules of different chemical classes, the exact mode of action of which is still unidentified. Newer agents include sulfonamides, thiadiazoles, semi- and thiosemicarbazones, pyrrolidine-2,5-diones, imidazoles, benzothiazoles and amino acid deriva tives. These new chemical entities can be useful for the design and development of forthcoming antiseizure agents.

Epileptiform discharges in EEG and seizure risk in adolescent children of women with epilepsy

We aimed to study the epileptiform discharges (ED) and seizure risk in EEG of 12-18-year-old children of women with epilepsy (WWE). Children of WWE who were prospectively followed up in the Kerala registry of epilepsy and pregnancy (KREP), aged 12-16years (n=92; males 48, females 44) underwent clinical evaluation and a 30-min digital 18-channel EEG. The EEG showed epileptiform discharges in 13 children (5 males and 8 females). The EDs were generalized in 9 and focal in 4 (occipital 2, frontal 1, and centroparietal 1). They had significantly higher risk of ED (odds ratio 4.02, 95% CI 1.04-15.51) when compared to published prevalence of ED in healthy children. There were 2 children with epilepsy (one with localization-related epilepsy and the other generalized epilepsy). The children under study had a trend towards higher prevalence of epilepsy (odds ratio 3.39, 95% CI 0.82-13.77) when compared to age specific prevalence of epilepsy from community surveys in same region. Children of WWE showed increased risk of ED in EEG and trend towards increased seizure risk when compared to healthy children.

Auditory processing assessment suggests that Wistar audiogenic rat neural networks are prone to entrainment

Epilepsy is a neurological disease related to the occurrence of pathological oscillatory activity, but the basic physiological mechanisms of seizure remain to be understood. Our working hypothesis is that specific sensory processing circuits may present abnormally enhanced predisposition for coordinated firing in the dysfunctional brain. Such facilitated entrainment could share a similar mechanistic process as those expediting the propagation of epileptiform activity throughout the brain. To test this hypothesis, we employed the Wistar audiogenic rat (WAR) reflex animal model, which is characterized by having seizures triggered reliably by sound. Sound stimulation was modulated in amplitude to produce an auditory steady-state-evoked response (ASSR; -53.71Hz) that covers bottom-up and top-down processing in a time scale compatible with the dynamics of the epileptic condition. Data from inferior colliculus (IC) c-Fos immunohistochemistry and electrographic recordings were gathered for both the control Wistar group and WARs. Under 85-dB SLP auditory stimulation, compared to controls, the WARs presented higher number of Fos-positive cells (at IC and auditory temporal lobe) and a significant increase in ASSR-normalized energy. Similarly, the 110-dB SLP sound stimulation also statistically increased ASSR-normalized energy during ictal and post-ictal periods. However, at the transition from the physiological to pathological state (pre-ictal period), the WAR ASSR analysis demonstrated a decline in normalized energy and a significant increase in circular variance values compared to that of controls. These results indicate an enhanced coordinated firing state for WARs, except immediately before seizure onset (suggesting pre-ictal neuronal desynchronization with external sensory drive). These results suggest a competing myriad of interferences among different networks that after seizure onset converge to a massive oscillatory circuit.

Epileptiform activity in the electroencephalogram of 6-year-old children of women with epilepsy

Purpose:

To study the epileptiform discharges (EDs) in the electroencephalogram (EEG) of 6-8-year-old children of women with epilepsy (WWE).

Materials and Methods:

All children born to women with epilepsy and prospectively followed up through the Kerala Registry of Epilepsy and Pregnancy (KREP), aged 6–8 years, were invited (n = 532). Out of the 254 children who responded, clinical evaluations and a 30-min digital 18 channel EEG were completed in 185 children.

Results:

Of the 185 children examined, 37 (20%) children (19 males, 18 females) had ED in their EEG. The EDs were generalized in 7 children, and focal in 30 children. The EDs were present in the sleep record only of 16 (43%) children and in the awake record only of 6 (16%) children. Out of the 94 children for whom seizure history was available, 7 children (7.4%) had seizures (neonatal seizures: 4, febrile seizure: 1, and single nonfebrile seizure: 2) and none had history of epilepsy or recurrent nonfebrile seizures. The odds ratio (OR) for occurrence of ED in the EEG was significantly higher for children of WWE [OR = 3.5, 95% confidence interval (CI) 2.3-6.0] when compared to the published data for age-matched children of mothers without epilepsy. There was no association between the occurrence of ED and the children's maternal characteristics [epilepsy syndrome, seizures during pregnancy, maternal intelligence quotient (IQ)] or the children's characteristics [antenatal exposure to specific antiepileptic drugs (AEDs), birth weight, malformations, IQ].

Conclusion:

Children of WWE have a higher risk of epileptiform activity in their EEG when compared to healthy children in the community though none had recurrent seizures.

Consanguinity and epilepsy in Oran, Algeria: A case-control study

PURPOSE

The goal of this case-control study was to identify the significance of consanguinity and other risk factors for epilepsy in Oran, Algeria.

METHODS

Unrelated epileptic patients upwards of 16 years, who attended the Neurology Department between October 2013 and March 2014 were included in the study. Controls, matched for age and sex, were selected among non-epileptic patients attending the same department during the same period. The risk factors evaluated were: consanguinity, family history of epilepsy, perinatal complications, infection of the central nervous system, mental retardation, neurological impairment, history of febrile seizures, severe head trauma, cerebrovascular diseases, and addiction.

RESULTS

101 cases and 202 controls participated in the study. Multivariate logistic regression identified five factors significantly associated with epilepsy: first-degree of consanguinity (odds ratio (OR)=2.15), history of epilepsy in first-degree relatives (OR=4.03), antecedent of febrile seizures (OR=5.38), severe head injury (OR=2.94) and mental retardation (OR=9.32).

CONCLUSION

Consanguinity, family history of epilepsy, history of febrile seizures, severe head trauma and mental retardation are risk factors for epilepsy. The implementation of a strategy for prevention and awareness of the impact of consanguineous marriages as well as genetic counseling for couples with a family history of epilepsy are needed.

Advances in epilepsy genetics and genomics

Current and emerging technologies for mutation identification are changing the landscape of genetics and accelerating the pace of discovery. Application of high throughput genomic analysis to epilepsy will advance our understanding of the genetic contribution to common forms of epilepsy and suggest novel therapeutic strategies for improved treatment.

A genetic epidemiological survey of idiopathic epilepsy in the Chinese Han population

BACKGROUND

Idiopathic epilepsy (IE) is a syndrome that comprises epilepsy only, with no underlying structural brain lesion or other neurological signs or symptoms. Numerous studies have shown that genetic factors play an important role in IE. IE is a common disease in the Chinese Han population. However, the genetic epidemiological characteristics of IE in the Chinese population, such as its heritability and genetic models remain unclear.

PURPOSE

To study the clinical and epidemiological profile of IE, to estimate the heritability and determine the possible genetic models for IE in the Chinese Han population.

METHODS

A case-control family-based study was carried out in a rural Chinese county. We collected data from eligible IE patients, controls, and their relatives by a uniform structured questionnaire, and then established an epidemiologic database of epilepsy using Access2010. General statistical and genetic epidemiological analyses (Falconer's-method-based heritability, simple segregation ratio and complex segregation analysis) were performed using SAS9.1 and the SAGE-SEGREG program.

RESULTS

(1) The prevalence of IE among the relatives of probands with IE (2.75‰) was higher than that among the relatives of the control group (0.61‰). The prevalence of IE among the first-, second-, and third-degree relatives of the probands with IE was 11.45‰, 2.64‰ and 0.98‰, respectively, which were all higher than the corresponding prevalences in the relatives of controls. Trend-chi-squared tests indicated that the prevalence of epilepsy increased among the relatives of probands with decreasing kinship distance (χ(2)=97.16, P=0.00). (2) The heritability of IE among first-, second-, and third-degree relatives was 55.06%, 50.72% and 16.98%, respectively. The weighted mean heritability was 46.07%. (3) The simple segregation ratio of IE was 0.03, significantly lower than the Mendelian recessive segregation ratio of 0.25. Complex segregation analysis showed that the population we studied accepted a Mendelian genetic model (dominant, recessive, additive, and a major gene model) and excluded the general model, non-transmitted model, and environment-only model. A Mendelian additive inheritance model was ultimately the best-fit because it had the lowest Akaike Information Criteria score.

CONCLUSION

In the Chinese Han population, IE follows a pattern of polygenic Mendelian additive inheritance rather than single-gene inheritance. Nearly half of the total variance can be explained by genetic factors.

Multicultural challenges in epilepsy

Epilepsy is a common neurological condition throughout the world. Its care involves medical expertise, but may also bring different cultural challenges. We discuss clinical, social and psychological outcomes in different cultural settings. We point out differences and similarities in epilepsy epidemiology (etiology and risk factors, prognosis, and natural history), disparities in care and health services, and cultural influences and traditional beliefs, with special respect to practical issues and possible transcultural misunderstandings. We also discuss the relevance of multicultural issues to clinicians working in developed countries.

Risk factors for epilepsy: a population-based case-control study in Kerala, southern India

We undertook a community-based case-control study on persons with active epilepsy residing in Kerala, southern India. Using a standardized questionnaire, we collected information from 362 cases and 362 controls. In the final multivariate model, family history of epilepsy (odds ratio=7.8, 95% confidence interval=3.2-18.8, P=0.000), antecedent history of febrile seizures (7.7, 4.3-14.0, 0.000), birth by complicated delivery (6.8, 2.1-21.8, 0.001), and neonatal seizures (7.8, 1.7-35.4, 008) emerged as strong independent predictors of epilepsy, followed in decreasing order by mental retardation, prematurity, maternal age 30, perinatal distress, and incomplete immunization. There were more similarities than differences in the distribution of risk factors between generalized and localization-related epilepsy syndromes. Our findings suggest interplay between genetic and acquired factors in the pathogenesis of epilepsies, and underscore the need for improvement in obstetric and neonatal care to minimize the epilepsy burden in low-income countries.

Epidemiology, aetiology, and clinical management of epilepsy in Asia: a systematic review

Epilepsy is a significant, but often underappreciated, health problem in Asia. Here, we systematically review the literature on epidemiology, aetiology, and management of epilepsy in 23 Asian countries. Prevalence estimates are available for only 11 countries from door-to-door surveys and are generally low. Figures for annual incidence in China and India are similar to those in the USA and Europe but lower than those reported from Africa and Latin America. There is a peak in incidence and prevalence in childhood, but a second peak in elderly people, as seen in developed countries, has not been documented. The main causes are head injuries, cerebrovascular disease, CNS infections, and birth trauma. Availability of epilepsy care depends largely on economic factors. Imaging and neurophysiological facilities are available in most countries, but often only in urban centres. Costly drugs, a large treatment gap, limited epilepsy surgery, and negative public attitude to epilepsy are other notable features of management in Asia. An understanding of the psychosocial, cultural, economic, organisational, and political factors influencing epilepsy causation, management, and outcome should be of high priority for future investigations.

Juvenile myoclonic epilepsy: epidemiology, pathophysiology, and management

Juvenile myoclonic epilepsy (JME) is a common epilepsy syndrome that begins most frequently in the early teenage years. It is officially classified as a type of idiopathic generalized epilepsy and is often under-recognized or misdiagnosed. This syndrome has a strong genetic component with multiple gene mutations being associated with the clinical presentation. Based upon genetic associations, there may be multiple pathophysiologic mechanisms for the disorder; the pathophysiology has not been clearly defined. A diagnosis of JME is made using the clinical history and EEG findings. Valproic acid is the primary antiepileptic drug (AED) used for JME, but some newer AEDs may be effective alternatives. Selection of an appropriate AED is essential to the proper management of JME, because of the possibility of exacerbation of seizures by some AEDs and the adverse effect profiles of effective drugs. It is important for clinicians to understand JME to correctly diagnose and manage patients with this syndrome.