Abstracts

Rationale: To analize retrospectively the impact of Zonisamide (ZNS) on the EEG and clinical features of a group patients initially diagnosed of West Syndrome with a variable degree of encefalophathy and epilepsy severity.Methods: Six patients (5 male, 1 female) 6 to 9 years old diagnosed of West Syndrome in their first year of life studied with serial EEG. Five patients were cryptogenic West syndrome and one was secondary to tuberous sclerosis. All patients showed a variable degree of psicomotor delay and several types of seizures, mainly atonic, myoclonic, atipical absences amb complex partial seizures. Due to the persistance of clinical seizures, in spite of polipharmacy, ZNS was added in up titration (600 mg / 24 h. maximal dose). In order to analize the impact of ZNS in these patients, we consider the clinical response and an EEG parameter, the spike density, obtained dividing the total number of spikes by the EEG duration. Automatic detection of spikes with posterior visual validation was performed to determine the number of spikes, and we analized two EEG maximum five months both prior and posterior to the introduction of ZNS, and an EEG post maximal dosage. Results: All patients except two showed a clear reduction, higher than 50%, in seizure frequency and in spike density parameter (Table I) after ZNS addition. These two patients (red lines in Table I), both initially cryptogenic West syndrome, had by far the worse evolution of the group, both in terms of cognitive deterioration and epilepsy severity, and the decay of spike density was small. In the other four patients, the timing of improvement was not uniform: Two patients had a rapid decay in spike density, previous to the achievement of the maximal dosage, in the other two the improvement was slower. No serious adverse reactions were reported in any patient. Conclusions: Previous studies has demostrated that ZNS can be effective for the initial treatment of West syndrome. In our experience, this drug is also effective and well tolerated in those West patients whose evolution hasn’t been good, in spite of the several pharmacological treatments tried, as is also reflected in the improvement of the parameters of the serial EEG, specially spike density.