Abstracts

EEG is an important tool for the diagnose of Benign Childhood Epilepsy (BCE) making other expensive tests, such as MRI, non-mandatory, but some Focal Symptomatic Epilepsies (FSE) can be overlooked when the diagnose is only based on clinical and EEG data. Also, epileptiform paroxysms (EP), typical of BCE, can occur in non-epileptic children, as a genetic trace (GT), a source of misdiagnose. We tried to identify EEG characteristics more specific of BCE as compared to FSE and GT. EEG recordings of children with normal background activity and EP suggestive of BCE, registered in our lab along 1993 and 1994, were blindly collected and lately confronted with clinical and neuroimaging data of the patients (follow-up of 3 to 13 years). We carried out a conventional analysis of the following characteristics of the EP: number and location of the foci, electrical fields, presence of tangential dipole, association of the spikes with a slow wave, presence of pseudo-slowing, EP with double-spike, sleep activation, presence of bisynchronous spikes and/or generalized spike-wave. We reviewed 173 EEG from 145 children, diagnosed as BEC (80), GT (38), FSE(25) and Landau-Kleffner Syndrome (2). Among BEC, we found 65 (81.3%) with Rolandic Epilepsy, 9 (11.2%) with Occipital Panayotopoulos-type Epilepsy, 4 (5%) with Occipital Gastaut-type Epilepsy, 1 (1.2%) with BEC with Affective Symptoms and 1 with Infantile Benign Focal Epilepsy. None of the EEG characteristics studied were significantly more common in BEC as compared to the other two groups. There seems to be superposition of the EEG characteristics between some FSE and BCE, which makes accurate clinical and neuroimaging tests necessary for their differentiation in some cases. Our results suggest that the morphology, location, field distribution (including tangential dipole) and sleep activation, among other aspects of the EP, under a normal background EEG activity, are not always enough to discriminate those syndromes. (Supported by FAEPA - Support Foundation to Teaching, Research and Assistance of Ribeirao Preto Medical School - University of Sao Paulo)