Electroencephalography as a tool for evidence-based diagnosis and improved outcomes in children with epilepsy in a resource-poor setting

Introduction Electroencephalography (EEG) remains the most important investigative modality in the diagnostic evaluation of individuals with epilepsy. Children living with epilepsy in the developing world are faced with challenges of lack of access to appropriate diagnostic evaluation and a high risk of misdiagnosis and inappropriate therapy. We appraised EEG studies in a cohort of Nigerian children with epilepsy seen in a tertiary center in order to evaluate access to and the impact of EEG in the diagnostic evaluation of the cases. Methods Inter-ictal EEG was requested in all cases of pediatric epilepsy seen at the pediatric neurology clinic of the University College Hospital, Ibadan, Nigeria over a period of 18 months. Clinical diagnosis without EEG evaluation was compared with the final diagnosis post- EEG evaluation. Results A total of 329 EEGs were recorded in 329 children, aged 3months to 16 years, median 61.0 months. Clinical evaluation pre-EEG classified 69.3% of the epilepsies as generalized. The a posteriori EEG evaluations showed a considerably higher proportion of localization-related epilepsies (33.6%). The final evaluation post EEG showed a 21% reduction in the proportion of cases labeled as generalized epilepsy and a 55% increase in cases of localization-related epilepsy(p<0.001). Conclusion Here we show that there is a high risk of misdiagnosis and therefore the use of inappropriate therapies in children with epilepsy in the absence of EEG evaluation. The implications of our findings in the resource-poor country scenario are key for reducing the burden of care and cost of epilepsy treatment on both the caregivers and the already overloaded tertiary care services.


Introduction
Electroencephalography (EEG) remains the most important investigative modality in the diagnostic evaluation individuals with epilepsy [1]. Although the diagnosis of epilepsy is clinical, EEG helps to establish the diagnosis of epilepsy, distinguish epileptic seizures from other non-epileptic events, determine the site of seizure origin and the classification of epilepsy and epilepsy syndromes [1,2]. It helps in characterizing seizures for the purpose of treatment and it is also quite useful in prognosticating. Conventionally, epilepsy is divided into 2 broad classes; generalized and focal epilepsies and EEG has been shown to be valuable in making this distinction [3].
Misinterpretation of EEG abnormalities and lack of access to EEG evaluation are known to result in misclassification and misdiagnosis of epilepsy by physicians and prescription of inappropriate antiepileptic drugs (AEDs) [4,5]. Although routine inter-ictal EEG is more readily performed, continuous EEG has been shown to increase the chances of identifying epileptiform discharges in individuals with epilepsy. It is more likely to capture a seizure, capture a subclinical seizure and exclude a seizure in the patient who presents with a concerning event than routine EEG [6].
The duration of EEG recording varies among laboratories and several recommendations have been published. Craciun and colleagues in a review of 1,005 EEG recordings provided evidence for recommending at least 20 minutes recording duration for standard awake EEG and 30 minutes for sleep EEG in patients with epilepsy-related indications [7]. Electroencephalographic findings have also been reported to be useful in prognosticating in children with newly-diagnosed epilepsy and genetic generalized epilepsies [8,9]. There is a huge burden of epilepsy in the developing countries of the world, with about 10 million persons living with epilepsy in Africa [10]. Epilepsy care in many resource-poor developing countries faces multiple challenges, which include inadequatetrained personnel, limitedaccess to EEG and other diagnostic tools, as well as lack of anti-epileptic drugs [11] head trauma are known to be major contributors to symptomatic epilepsy in Africa [17,18].
We show a marked reduction in the proportion of cases labeled as generalized epilepsy on clinical evaluation after the benefit of EEG.
Many studies from other resource poor developing countries have consistently reported generalized seizures as the predominant seizure type in epilepsy and several of these studies have reported limited access to EEG as a major limitation [19,20]. remission, which will in turn affect morbidity and mortality on these patients.

Conclusion
Our study provides evidence that reinforces the need for routine EEG evaluation in all children with epilepsy, even in resource-poor settings. Indeed, facilitating access to EEG services both in urban and in rural settings of resource-poor regions of the World will, in the long run, be one of the most cost-effective intervention allowing the accurate diagnosis and treatment of children with epilepsy. This approach to the management of epilepsy will therefore improve outcomes in children with epilepsy and ultimately reduce the burden of care and cost of epilepsy on both the caregivers and the already overloaded tertiary-care public health systems.We must emphasize that there is an urgent need to improve access to EEG evaluation in individuals with epilepsy in the resource-poor countries of the world where the burden of epilepsy resides in large numbers.
the study. We also thank Dr Bola Orimadegun and the EEG technologists, Mr Oladipo and Mr Bunmi Akinyemi for their contributions to this work.