Abstracts

Hypsarritmia is a well-known EEG pattern that usually appears associated to a severe form of infantile epilepsy. Different patterns of hypsarritmia are recognizable on visual analysis, making it difficult to correlate to outcome. In this study we propose the use of scales for objective analysis of EEG background and hypsarritmia, searching for predictors of EEG outcome in West Syndrome. EEGs of children with diagnosis of West Syndrome and infantile spasms were analyzed. Patients were included in the study between October 2002 to October 2004. EEG background parameters encompassed presence of background gradient, amount of delta activity, sleep spindles and assimetry; hypsarritmia parameters included amplitude and percentage of hypsarritmia in the EEG record. Patients were divided in controlled (group 1) and uncontrolled (group 2) and their scores compared. Clinical variables including age of onset of spasms, age at the time of the examination, previous use of antiepileptic drugs, etiology and MRI data were additionally analyzed . 24 EEGs were assessed and scored. Global scores varied from 7 to 18, background scores from 2 to 12, and hypsarritmia scores from 4 to 9, respectively (groups 1 and 2). Age of onset of spasms were classified as early onset, classical and late onset, and the global EEG scores were 11.8 (sd=2.28), 12.61 (sd=3.09) and 13, respectively. Differences were not statiscally significant. Patients[apos]age at the time of the evaluation were also divided in up to 4 months, 4 to 9 months, 9 to 12 months and over 12 months. Global EEG scores regarding patients[apos] age were, respectively 14, 12.50 (sd=3.12); 11.67(sd=2.50) and 12.78 (sd=3.15). There was no correlation between EEG scores and duration of epilepsy, etiology, MRI findings. Lower scores were found in controlled patients, while higher scores in uncontrolled patients. Overall, only background scores were correlated with outcome. In patients with West syndrome EEG scores were not affected by clinical and etiological data. Global EEG scores do not have prognostic value, but background scores were predictive of EEG outcome (Supported by FAPESP.)