[Assessment of EEG in children with partial epilepsy]

Diagnosis of the focal epilepsy is possible even based on the clinical history. More precise identification of bioelectrical focus, type of epileptic attack and type of epilepsy requires EEG or videoEEG analysis.

The aim of the study was to assess clinical value of electro-encephalography and videoelectro-encephalography in diagnostics of partial epilepsy in children.

The study group consisted of 140 children with partial epilepsy hospitalized between 1998 and 2004 in Department of Pediatric Neurology, Jagiellonian University, Krakow. The group included 70 girls and 70 boys, aged from 2 months to 17 years. 38 of the children were older than 5 years, with mean age 8 years and 4 months. The mean time of the epilepsy course was 2 years and 4 months. Children with symptomatic partial epilepsy were the biggest group and children with idiopathic partial epilepsy were in minority. More than 50% of children suffered from complex partial seizures. Statistical correlation of the EEG results and pregnancy and birth period factors, results of neurological and psychological examination was performed. All children underwent MRI and 15 HMRS neuroimaging as well. All children underwent EEG examinations and 55 children videoEEG, recording time 60 minutes for each patient. Sleep recording in 40 children, awake EEG in 93 children and both type recordings in 8 children were performed. Stroboscope, hyperventilation and sleep deprivation stimulation tests were used. All EEG recordings were assessed by 2 physicians with the EEG license and final result was a mean of their assessment. T-student test, Mann-Whitney and bilateral Fisher test were used in statistical analysis.

EEG pattern was abnormal in 139/140 children, and videoEEG in all 55 children. In the vast majority of the patients with partial epilepsy focal EEG changes were recorded (in 111/140), with a significant prevalence of unilateral changes observed in 48/111 patients. 34 children had focal EEG changes with one-site prevalence and 27/140 children had focal EEG changes in both hemispheres without any prevalence. Generalized EEG changes were revealed in 16/140 children. Hyperventilation revealed in 8 children paroxysmal bioelectric activity and in 43 enhanced abnormal EEG pattern. In all children with normal MRI imaging EEG/videoEEG methods revealed changes significant for localization of seizures onset and origin.

(1) EEG patterns in children with partial epilepsy were dominated by localized and lateralized changes. EEG was crucial for localization of bioelectric foci especially in children with normal MRI. (2) Focal EEG changes were significantly more often in children with hippocampal sclerosis. (3) In terms of localization HMRS were more compatible with EEG than with MRI findings. HMRS examination is strongly indicated especially in children with EEG localized discharges and with normal brain MRI.