Electroencephalographic features of convulsive epilepsy in Africa: A multicentre study of prevalence, pattern and associated factors

Magnetic resonance imaging findings in Kenyans and South Africans with active convulsive epilepsy: An observational study

OBJECTIVE

Focal epilepsy is common in low- and middle-income countries. The frequency and nature of possible underlying structural brain abnormalities have, however, not been fully assessed.

METHODS

We evaluated the possible structural causes of epilepsy in 331 people with epilepsy (240 from Kenya and 91 from South Africa) identified from community surveys of active convulsive epilepsy. Magnetic resonance imaging (MRI) scans were acquired on 1.5-Tesla scanners to determine the frequency and nature of any underlying lesions. We estimated the prevalence of these abnormalities using Bayesian priors (from an earlier pilot study) and observed data (from this study). We used a mixed-effect modified Poisson regression approach with the site as a random effect to determine the clinical features associated with neuropathology.

RESULTS

MRI abnormalities were found in 140 of 240 (modeled prevalence = 59%, 95% confidence interval [CI]: 53%-64%) of people with epilepsy in Kenya, and in 62 of 91 (modeled prevalence = 65%, 95% CI: 57%-73%) in South Africa, with a pooled modeled prevalence of 61% (95% CI: 56%-66%). Abnormalities were common in those with a history of adverse perinatal events (15/23 [65%, 95% CI: 43%-84%]), exposure to parasitic infections (83/120 [69%, 95% CI: 60%-77%]) and focal electroencephalographic features (97/142 [68%, 95% CI: 60%-76%]), but less frequent in individuals with generalized electroencephalographic features (44/99 [44%, 95% CI: 34%-55%]). Most abnormalities were potentially epileptogenic (167/202, 82%), of which mesial temporal sclerosis (43%) and gliosis (34%) were the most frequent. Abnormalities were associated with co-occurrence of generalized non-convulsive seizures (relative risk [RR] = 1.12, 95% CI: 1.04-1.25), lack of family history of seizures (RR = 0.91, 0.86-0.96), convulsive status epilepticus (RR = 1.14, 1.08-1.21), frequent seizures (RR = 1.12, 1.04-1.20), and reported use of anti-seizure medication (RR = 1.22, 1.18-1.26).

SIGNIFICANCE

MRI identified pathologies are common in people with epilepsy in Kenya and South Africa. Mesial temporal sclerosis, the most common abnormality, may be amenable to surgical correction. MRI may have a diagnostic value in rural Africa, but future longitudinal studies should examine the prognostic role.

Neuropsychology and Electroencephalography in Rural Children at Neurodevelopmental Risk: A Scoping Review

Children from rural areas face numerous possibilities of neurodevelopmental conditions that may compromise their well-being and optimal development. Neuropsychology and electroencephalography (EEG) have shown strong agreement in detecting correlations between these two variables and suggest an association with specific environmental and social risk factors. The present scoping review aims to describe studies reporting associations between EEG features and cognitive impairment in children from rural or vulnerable environments and describe the main risk factors influencing EEG abnormalities in these children. The method for this purpose was based on a string-based review from PubMed, EBSCOhost, and Web of Science, following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). Qualitative and quantitative analyses were conducted from the outcomes that complied with the selected criteria. In total, 2280 records were identified; however, only 26 were eligible: 15 for qualitative and 11 for quantitative analysis. The findings highlight the significant literature on EEG and its relationship with cognitive impairment from studies in children with epilepsy and malnutrition. In general, there is evidence for the advantages of implementing EEG diagnosis and research techniques in children living under risk conditions. Specific associations between particular EEG features and cognitive impairment are described in the reviewed literature in children. Further research is needed to better describe and integrate the state of the art regarding EEG feature extraction.

HAPPILEE: HAPPE In Low Electrode Electroencephalography, a standardized pre-processing software for lower density recordings

Lower-density Electroencephalography (EEG) recordings (from 1 to approximately 32 electrodes) are widely-used in research and clinical practice and enable scalable brain function measurement across a variety of settings and populations. Though a number of automated pipelines have recently been proposed to standardize and optimize EEG pre-processing for high-density systems with state-of-the-art methods, few solutions have emerged that are compatible with lower-density systems. However, lower-density data often include long recording times and/or large sample sizes that would benefit from similar standardization and automation with contemporary methods. To address this need, we propose the HAPPE In Low Electrode Electroencephalography (HAPPILEE) pipeline as a standardized, automated pipeline optimized for EEG recordings with lower density channel layouts of any size. HAPPILEE processes task-free (e.g., resting-state) and task-related EEG (including event-related potential data by interfacing with the HAPPE+ER pipeline), from raw files through a series of processing steps including filtering, line noise reduction, bad channel detection, artifact correction from continuous data, segmentation, and bad segment rejection that have all been optimized for lower density data. HAPPILEE also includes post-processing reports of data and pipeline quality metrics to facilitate the evaluation and reporting of data quality and processing-related changes to the data in a standardized manner. Here the HAPPILEE steps and their optimization with both recorded and simulated EEG data are described. HAPPILEE's performance is then compared relative to other artifact correction and rejection strategies. The HAPPILEE pipeline is freely available as part of HAPPE 2.0 software under the terms of the GNU General Public License at: https://github.com/PINE-Lab/HAPPE.

Exposure to parasitic infections determines features and phenotypes of active convulsive epilepsy in Africa

Background: Epilepsy affects 70 million people worldwide, 80% of whom are in low-and-middle income countries (LMICs). Parasitic infections contribute considerably to the burden of epilepsy in LMICs, but the nature and presentation of epilepsy following these infections is not fully understood. We examined if epilepsy outcomes are associated with the exposure to parasitic infections. Methods: This was a case-comparison study nested in a cross-sectional survey of people with active convulsive epilepsy, with cases as those exposed to parasitic infections, and comparison as those unexposed. Associations of exposure to parasites with clinical and electroencephalographic features of epilepsy were done using a modified mixed effects Poisson regression model across five sites in Africa. Multiplicative and additive scale (RERI) interactions were explored to determine the effect of co-infections on epilepsy features. Population attributable fractions (PAF) were calculated to determine the proportion of severe clinical and electroencephalographic features of epilepsy attributable to parasitic infections. Results: A total of 997 participants with active convulsive epilepsy from the five African sites were analyzed, 51% of whom were males. Exposure to parasitic infections was associated with more frequent seizures in adult epilepsy (relative risk (RR)=2.58, 95% confidence interval (95%CI):1.71-3.89). In children, exposure to any parasite was associated with convulsive status epilepticus (RR=4.68, (95%CI: 3.79-5.78), intellectual disabilities (RR=2.13, 95%CI: 1.35-3.34) and neurological deficits (RR=1.92, 95%CI: 1.42-2.61). Toxoplasma gondii and Onchocerca volvulus interacted synergistically to increase the risk of status epilepticus (RERI=0.91, 95%CI=0.48-1.35) in the data pooled across the sites. Exposure to parasitic infections contributed to 30% of severe features of epilepsy as shown by PAF. Conclusions: Parasitic infections may determine features and phenotypes of epilepsy through synergistic or antagonistic interactions, which can be different in children and adults.  Interventions to control or manage infections may reduce complications and improve prognosis in people with epilepsy.

Seizure control and its associated factors among epileptic patients at Neurology Clinic, University of Gondar hospital, Northwest Ethiopia

Background

Epilepsy is characterized by two or more unprovoked recurrent seizures, which often respond to available antiseizure medications. However, seizure control among epileptic patients in the developing world is low. Factors determining seizure control among epileptic patients were not evidently explored in the study setting.

Objectives

This study aimed to determine the magnitude of uncontrolled seizures and associated factors among epileptic patients at the University of Gondar hospital.

Methods

This cross-sectional study was conducted at the University of Gondar hospital, Northwest Ethiopia. A convenience sampling method was used to recruit study subjects. Controlled seizure was defined as seizure freedom for the past 1 year. Logistic regression analysis was used to identify factors associated with seizure control. A p-value < 0.05 was used to declare a significant association.

Results

A total of 320 study subjects were included in the study. The mean (±SD) age of patients was 27.5 ± 7.6 years. More than half (182/320, 57%) of epileptic patients had uncontrolled seizures. Five or more pretreatment seizure episodes (adjusted odds ratio = 3.98, 95% confidence interval: 1.81-8.75, p = 0.001), less than 2 years on anti-seizure medications (adjusted odds ratio = 8.64, 95% confidence interval: 3.27-22.85, p < 0.001), taking 2 or more ASMs (adjusted odds ratio = 2.48, 95% confidence interval: 1.23-5.02, p = 0.011), poor adherence to ASMs (adjusted odds ratio = 9.37, 95% confidence interval: 4.04-21.75, p < 0.001), and living at a single trip distance from hospital equaled 1 h or more (adjusted odds ratio = 4.20, 95% confidence interval: 2.11-8.41, p < 0.001) were significantly associated with uncontrolled seizures.

Conclusion

The dose of a preferred anti-seizure medication should be optimized before combinations of anti-seizure medications are used. Adherence to anti-seizure medications should be reinforced for better seizure control. Epilepsy care should be integrated into primary health care services in the catchment region.

Evaluation of the International League Against Epilepsy 1981, 1989, and 2017 classifications of seizure semiology and etiology in a population-based cohort of children and adults with epilepsy

Objective

The International League Against Epilepsy (ILAE) has revised the classification of epilepsies and seizures on several occasions since the original classification published in 1964. It is unclear if these changes have impacted the characterization of epilepsy, including the clinical validity of seizure semiology or epilepsy outcomes in resource‐poor areas. We aim to address this important knowledge gap.

Methods

We reviewed the clinical seizure semiology and etiological data of 483 persons with epilepsy identified from a population‐based survey in rural Kenya. The seizure semiology and etiological data were classified using the 1981 (for seizures) and 1989 (for epilepsy) ILAE criteria and then reclassified according to the ILAE‐2017 criteria. Logistic regression models adjusted for potential confounders were used to measure the associations between the seizure semiology and different clinical and electroencephalographic features of epilepsy.

Results

Focal (formerly localization‐related) and generalized epilepsies were lower in ILAE‐2017 (56% and 29%) than that of ILAE‐1989 (61% and 34%), P < .001 and P < .001. Combined focal and generalized epilepsy type in ILAE‐2017 accounted for 11% of epilepsies. Individual seizure types were statistically similar in both ILAE‐1981 and 2017. New classification categories in ILAE‐2017 such as unknown seizures and epilepsies were identified, and the proportions were similar to the unclassified category in ILAE‐1989, 6% and 5%, respectively. The most common causes of epilepsy were symptomatic (76%) in the ILAE‐1989 criteria, with infectious (45%) and structural (36%) causes were highest in the ILAE‐2017 criteria.

Significance

Our study confirms that the two ILAE classification schemes are broadly consistent, but the introduction of the combined onset seizure category in ILAE‐2017 significantly reduces the proportion of mutually exclusive focal and generalized seizures. The comprehensive classification of etiology categories in ILAE‐2017 will facilitate appropriate treatment and improve prognosis.

Exposure to parasitic infections determines features and phenotypes of active convulsive epilepsy in Africa

Background: Epilepsy affects 70 million people worldwide, 80% of whom are in low-and-middle income countries (LMICs). Infections of the central nervous system (CNS) contribute considerably to the burden of epilepsy in LMICs, but the nature and presentation of epilepsy following these infections is not fully understood. We examined if epilepsy foutcomes are associated with the exposure to parasitic infections. Methods: This was a case-comparison study nested in a cross-sectional survey of people with active convulsive epilepsy, with cases as those exposed to parasitic infections, and comparison as those unexposed. Associations of exposure to parasites with clinical and electroencephalographic features of epilepsy were done using a modified mixed effects Poisson regression model across five sites in Africa. Multiplicative and additive scale (RERI) interactions were explored to determine the effect of co-infections on epilepsy features. Population attributable fractions (PAF) were calculated to determine the proportion of severe clinical and electroencephalographic features of epilepsy attributable to CNS infections. Results: A total of 997 participants with active convulsive epilepsy from the five African sites were analyzed, 51% of whom were males. Exposure to parasitic infections was associated with more frequent seizures in adult epilepsy (relative risk (RR)=2.58, 95% confidence interval (95%CI):1.71-3.89). In children, exposure to any parasite was associated with convulsive status epilepticus (RR=4.68, (95%CI: 3.79-5.78), intellectual disabilities (RR=2.13, 95%CI: 1.35-3.34) and neurological deficits (RR=1.92, 95%CI: 1.42-2.61). Toxoplasma gondii and Onchocerca volvulus interacted synergistically to increase the risk of status epilepticus (RERI=0.91, 95%CI=0.48-1.35) in the data pooled across the sites. Exposure to parasitic infections contributed to 30% of severe features of epilepsy as shown by PAF. Conclusions: Parasitic infections may determine features and phenotypes of epilepsy through synergistic or antagonistic interactions, which can be different in children and adults.  Interventions to control or manage infections may reduce complications and improve prognosis in epilepsy.

Electroencephalography findings in childhood epilepsy in a Saudi population: Yield, pattern and determinants of abnormality

OBJECTIVE

The study was designed to evaluate the yield, pattern, and factors that are independently associated with electroencephalography (EEG) abnormalities in childhood epilepsy in a Saudi population.

METHODS

We characterised the features of the first EEG and evaluated the associated factors in children with epilepsy in a Saudi population. The features of interictal epileptiform discharges (interictal epileptiform activity (IEA)) adopted by the International Federation of Societies for Electroencephalography and Clinical Neurophysiology were used in the study.

RESULT

A total of 756 paediatric patients, comprised of 427 men (56.5%) and 329 women (43.5%) with a clinical diagnosis of epilepsy, underwent EEG. Clinically, seizure was generalised in 619 (81.9%) patients and focal in 137 (18.1%). Among the patients, 397 (52.51%) had an abnormal EEG, while EEG was normal in 359 (47.49%) patients. Seizure frequency, gender, family history of epilepsy, and age were independent predictors of the presence of EEG abnormalities.

CONCLUSION

This study revealed a yield of 52% abnormal EEG findings in children with epilepsy. Age, gender, family history, and seizure frequency were independent predictors of the presence of EEG abnormalities in childhood epilepsy.

Evaluation of the efficiency of the web-based epilepsy education program (WEEP) for youth with epilepsy and parents: A randomized controlled trial

BACKGROUND

When youth with epilepsy and their parents have insufficient information about the disease, they are known to have more problems with disease management, and they show poor compliance. Providing accurate, reliable, and accessible information with no time and space limitations is extremely important for individuals with epilepsy as well as for their caregivers.

AIM

In this study, we aimed to evaluate the content, quality, usability, and efficacy of our web-based epilepsy education program (WEEP) that we developed for youth with epilepsy and their parents.

METHODS

The sample of this randomized controlled trail was composed of youth with epilepsy who were between the ages of 9 and 18 years and their parents who had applied to the Pediatric Neurology Unit of a tertiary healthcare hospital in Turkey between November 2017 and April 2018. This study was conducted in two stages: (1) the preparation phase, during which we developed a WEEP for epilepsy, and tested its content, quality, and usability; and (2) the implementation phase, during which we evaluated the efficacy of the website by assessing users' knowledge of epilepsy, seizure self-efficacy, attitudes, and e-health literacy. Before the implementation phase, data collection tools were used to test the prior knowledge of epilepsy of the participants and control groups. Next, the youth and their parents were asked to use the WEEP for 12 weeks, while a control group was not provided with additional education tools. Written consent was obtained from the participants prior to the study in addition to obtaining approval from the ethics committee and permission from the institution where the research was conducted. The data were finally analyzed using SAS 9.4 software.

RESULTS

During the preparation phase, the website was developed and tested for content, quality, and usability. The WEEP was graded 72.7 ± 3.4 points by experts, 92.4 ± 1.63 by youth with epilepsy, and 92.31 ± 1.94 by the parents. During the implementation phase, the efficacy of the web site was evaluated through the assessment of participants' scores. We found that the mean knowledge, seizure self-efficacy, attitude, and e-health literacy scores of youth with epilepsy in the experimental group had significantly increased after the WEEP (p < 0.05). An increase in the scores of knowledge, anxiety, self-management, and e-health literacy scale was also found among the parents in the intervention group (p < 0.05).

CONCLUSION

The content, quality, and usability of the WEEP were adequate and effective in improving knowledge, self-efficacy, attitudes, and e-health literacy of youth with epilepsy as well as those of their parents.

A retrospective observational study of EEG findings and antiepileptic drug use among children referred for EEG to Zambia's University Teaching Hospital

Objective

Despite the heavy burden of epilepsy in Sub‐Saharan Africa, there remains a relative paucity of neurophysiology services and limited published data on electroencephalography (EEG) features among African children. The aim of this study was to describe clinical characteristics, EEG findings, and antiepileptic drug (AED) use among children referred for EEG to the University Teaching Hospital in Zambia.

Methods

EEG referrals and reports from 2013–2015 were reviewed. Within the context of routine care, EEG studies were interpreted by readers with advanced training in child neurology and clinical neurophysiology. Clinical data provided in the referral including seizure semiology and EEG findings were systematically extracted and analyzed.

Results

A total of 1,217 EEG reports were reviewed, with 1,187 included in the analysis. Median age was 7 years (interquartile range [IQR] 3–11) and 57% were male. Seventy‐three percent of 554 had documented seizure onset before 5 years of age. Among the 23% with seizure etiology documented, 78% were associated with perinatal injuries and central nervous system (CNS) infections. EEG abnormalities were found in 75% of the studies. Clinical semiology per referral identified focal seizures in 29%, but EEG findings increased this proportion to 63% (p = 0.004). Sixty‐two percent were taking AEDs, with 85% on monotherapy. The most commonly used AED was carbamazepine (49%).There was no association between the choice of AED and clinical semiology (all p's > 0.05).

Significance

This tertiary care center study identified >60% of referred children to have localization‐related epilepsies, with at least 18% of epilepsies being from potentially preventable causes. These findings are consistent with multi‐country, population‐based data from elsewhere in Africa. Seizure semiology assessed in routine, nonspecialist care does not predict AED choice, and the presence of focality is underestimated in routine care.

Cognition, mood and quality-of-life outcomes among low literacy adults living with epilepsy in rural Kenya: A preliminary study

Epilepsy is frequently associated with neurocognitive impairments, mental health, and psychosocial problems but these are rarely documented in low- and middle-income countries. The aim of this study was to examine the neurocognitive outcomes, depressive symptoms, and psychosocial adjustments of people with epilepsy (PWE) in Kilifi, Kenya. We evaluated the impact of these outcomes on health-related quality of life. Self-report, interviewer-administered measures of depression (Major Depression Inventory) and quality of life (RAND SF-36) were administered to 63 PWE and 83 community controls. Neurocognitive functioning was assessed using Raven's Standard Progressive Matrices, Digit Span, and Contingency Naming Test. The results show that PWE have poorer scores for executive function, working memory, intelligence quotient (IQ), depression, and quality of life than controls. Twenty-seven (27%) of PWE had depressive symptoms, which was significantly greater than in controls (6%); P < 0.001. Quality-of-life scores were significantly lower in PWE with depressive symptoms than in those without depressive symptoms (Mean QoL scores (standard deviation (SD)): 46.43 (13.27) versus 64.18 (17.69); P = 0.01. On adjusted linear regression models, depression affected total quality-of-life scores (P = 0.07) as well as individual health indicator domains touching on pain (P = 0.04), lethargy/fatigue (P = 0.01), and emotional well-being (P = 0.02). Our results show that epilepsy is associated with a significant burden of mental health and neurocognitive impairments in the community; however, community-based studies are needed to provide precise estimates of these disorders.

Prevalence, risk factors and behavioural and emotional comorbidity of acute seizures in young Kenyan children: a population-based study

BACKGROUND

Acute symptomatic seizures and febrile seizures are common in children admitted to hospitals in Africa and may be markers of brain dysfunction. They may be associated with behavioural and emotional problems, but there are no published community-based studies in Africa.

METHODS

We screened 7047 children aged 1-6 years (randomly sampled from 50,000 in the community) for seizures (using seven questions) and invited those who screened positive and a proportion of negatives for a clinical assessment. Risk factors were identified using a parental questionnaire. Behavioural and emotional problems were examined using the Child Behaviour Checklist (CBCL) in 3273 children randomly selected from 7047. Generalised linear models with appropriate link functions were used to determine risk factors and associations between behavioural or emotional problems and acute seizures. Sobel-Goodman mediation tests were used to investigate if the association between acute seizures and CBCL scores was mediated by co-diagnosis of epilepsy.

RESULTS

Acute seizures were identified in 429 (6.1%) preschool children: 3.2% (95% confidence interval CI: 2.9-3.5%) for symptomatic seizures, and 2.9% (95% CI: 2.6-3.3%) for febrile seizures. Risk factors for acute seizures included family history of febrile seizures (odds ratio OR = 3.19; 95% CI: 2.03-5.01) and previous hospitalisation (OR = 6.65; 95% CI: 4.60-9.63). Total CBCL problems occurred more frequently in children with acute seizures (27%; 95% CI: 21-34%) than for those without seizures (11%; 95% CI: 11-12%; chi-squared p ≤ 0.001). Acute seizures were associated with total CBCL problems (adjusted risk ratio (aRR) = 1.92; 95% CI: 1.34-2.77), externalising problems (aRR = 1.82; 95% CI: 1.21-2.75) and internalising problems (aRR = 1.57; 95% CI: 1.22-2.02), with the proportion of the comorbidity mediated by a co-diagnosis of epilepsy being small (15.3%; 95% CI: 4.5-34.9%). Risk factors for this comorbidity included family history of febrile seizures (risk ratio (RR) = 3.36; 95% CI: 1.34-8.41), repetitive acute seizures (β = 0.36; 95% CI: 0.15-0.57) and focal acute seizures (RR = 1.80; 95% CI: 1.05-3.08).

CONCLUSIONS

Acute seizures are common in preschool children in this area and are associated with behavioural and emotional problems. Both conditions should be assessed and addressed in children.

Prevalence, risk factors, and neurobehavioral comorbidities of epilepsy in Kenyan children

Objective

To investigate the prevalence, risk factors, clinical features, and neurobehavioral comorbidities of epilepsy and acute symptomatic seizures in school‐aged children in Kilifi, Kenya.

Methods

Randomly selected children (N = 11,223) were screened for epilepsy and other neurodevelopmental disorders. Those who screened positive were invited for further clinical, electroencephalographic (EEG), and neuropsychological evaluations. Prevalence was measured by dividing cases by screened population, providing Agresti–Coull confidence intervals (CIs). Prevalence ratios were computed using log binomial regression, and odds ratios (ORs) were computed using logistic regression; both were implemented with generalized linear models. Attention‐deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and other neurodevelopmental impairments were assessed in cases and controls.

Results

Prevalence of lifetime epilepsy was 20.9 per 1,000 (95% CI = 18.4–23.7), and that of active epilepsy was 11.5 per 1,000 (95% CI = 9.7–13.6). Prevalence of acute symptomatic seizures was 68.8 per 1,000 (95% CI = 64.2–73.6). Acute symptomatic seizures preceded a diagnosis of epilepsy in 8% of children. Of 98 children diagnosed with epilepsy, focal seizures were seen in 79%, abnormal EEG was seen in 39%, and 83% were not receiving antiepileptic drugs. Childhood absence epilepsy and Lennox–Gastaut epilepsy were the most easily identifiable epilepsy syndromes. Perinatal complications, previous hospitalization, geophagia, and snoring were risk factors for epilepsy. Family history of seizures, abnormal pregnancy, previous hospitalization, and snoring were risk factors for acute symptomatic seizures. Neurobehavioral comorbidities were present in 54% of subjects with lifetime epilepsy and in 3% of controls, with associations for individual comorbidities being statistically significant: ADHD (OR = 14.55, 95% CI = 7.54–28.06), ASD (OR = 36.83, 95% CI = 7.97–170.14), and cognitive impairments (OR = 14.55, 95% CI = 3.52–60.14).

Significance

The burden of seizure disorders in this area is higher than in locations in high‐income countries, and can be reduced by preventing risk factors. A comprehensive management plan for neurobehavioral comorbidities of epilepsy should be incorporated into standard epilepsy care.

High prevalence of epilepsy in onchocerciasis endemic regions in the Democratic Republic of the Congo

BACKGROUND

An increased prevalence of epilepsy has been reported in many onchocerciasis endemic areas. The objective of this study was to determine the prevalence of epilepsy in onchocerciasis endemic areas in the Democratic Republic of the Congo (DRC) and investigate whether a higher annual intake of Ivermectin was associated with a lower prevalence of epilepsy.

METHODOLOGY/PRINCIPLE FINDINGS

Between July 2014 and February 2016, house-to-house epilepsy prevalence surveys were carried out in areas with a high level of onchocerciasis endemicity: 3 localities in the Bas-Uele, 24 in the Tshopo and 21 in the Ituri province. Ivermectin uptake was recorded for every household member. This database allowed a matched case-control pair subset to be created that enabled putative risk factors for epilepsy to be tested using univariate logistic regression models. Risk factors relating to onchocerciasis were tested using a multivariate random effects model. To identify presence of clusters of epilepsy cases, the Kulldorff's scan statistic was used. Of 12, 408 people examined in the different health areas 407 (3.3%) were found to have a history of epilepsy. A high prevalence of epilepsy was observed in health areas in the 3 provinces: 6.8-8.5% in Bas-Uele, 0.8-7.4% in Tshopo and 3.6-6.2% in Ituri. Median age of epilepsy onset was 9 years, and the modal age 12 years. The case control analysis demonstrated that before the appearance of epilepsy, compared to the same life period in controls, persons with epilepsy were around two times less likely (OR: 0.52; 95%CI: (0.28, 0.98)) to have taken Ivermectin than controls. After the appearance of epilepsy, there was no difference of Ivermectin intake between cases and controls. Only in Ituri, a significant cluster (p-value = 0.0001) was identified located around the Draju sample site area.

CONCLUSIONS

The prevalence of epilepsy in health areas in onchocerciasis endemic regions in the DRC was 2-10 times higher than in non-onchocerciasis endemic regions in Africa. Our data suggests that Ivermectin protects against epilepsy in an onchocerciasis endemic region. However, a prospective population based intervention study is needed to confirm this.

Prevalence of River Epilepsy in the Orientale Province in the Democratic Republic of the Congo

BACKGROUND

An increased prevalence of epilepsy has been reported in many onchocerciasis endemic areas.

OBJECTIVE

To determine the prevalence and distribution of epilepsy in an onchocerciasis endemic region in the Democratic Republic of the Congo (DRC).

DESIGN/METHODS

An epilepsy prevalence study was carried out in 2014, in two localities of the Bas-Uélé district, an onchocerciasis endemic region in the Orientale Province of the DRC. Risk factors for epilepsy were identified using a random effects logistic regression model and the distribution of epilepsy cases was investigated using the Moran's I statistic of spatial auto-correlation.

RESULTS

Among the 12,776 individuals of Dingila, 373 (2.9%) individuals with epilepsy were identified. In a house-to-house survey in Titule, 68 (2.3%) of the 2,908 people who participated in the survey were found to present episodes of epilepsy. Epilepsy showed a marked spatial pattern with clustering of cases occurring within and between adjacent households. Individual risk of epilepsy was found to be associated with living close to the nearest fast flowing river where blackflies (Diptera: Simuliidae)-the vector of Onchocerca volvulus-oviposit and breed.

CONCLUSIONS

The prevalence of epilepsy in villages in the Bas-Uélé district in the DRC was higher than in non-onchocerciasis endemic regions in Africa. Living close to a blackflies infested river was found to be a risk factor for epilepsy.