The relationship between the pathological types and scalp electroencephalography features in patients with focal cortical dysplasia and intractable epilepsy

Abstract

Objective To study the relationship between different pathological types of focal cortical dysplasia (FCD) and the morphology of epileptiform discharges on electroencephalography (EEG) in patients with intractable epilepsy.Methods Case series of 91 patients (male∶ female =54∶37),aged 12.7 ± 9.76 years,with histo-pathological diagnosis of FCD (based on the consensus classification proposed by an ad hoc Task Force of the ILAE Diagnostic Methods Commission).All patients were examined by long-term scalp video EEG monitoring before operation and were followed up at least 6 months after operation.The morphology of the interictal discharges on scalp EEG were divided into 4 types including no epileptiform discharges,spikes,poly-spikes and fast rhythms.The morphology of the seizure onset was also divided into 4 types including spikes,poly-spikes and/or fast rhythms,electro-decremental and unclassified.Results Of 91 patients,there were significant difference between different types of FCD in the morphology of interictal discharges (P =0.013) with polyspikes more common in FCD Ⅱ a and FCD Ⅱ b and fast rhythms more common in FCD]] a and spikes more common in FCD Ⅰ and FCD Ⅲ.But no relationship was found between the morphology of the seizure onset and FCD types (P =0.1976).Conclusions In patients with FCD and intractable epilepsy,the morphology of interictal discharges in scalp EEG is probably related to the pathological types of FCD. Key words: Focal cortical dysplasia; Intractable epilepsy ; Eelctroencephalography; Morphology