EPILESSIA OCCIPITALE IDIOPATICA: FLUTTUAZIONE DELLE ANOMALIE NEL CORSO DEL FOLLOW-UP EEG

The classification of epilepsies includes epilepsy with occipital paroxysms among the age-related idiopathic forms. Although not exclusive to this syndrome, occipital EEG paroxysms are considered both typical and necessary for diagnosis. Seizure semiology can vary depending on spreading of ictal discharge, yet versive seizures associated with vomiting and impairment of consciousness seem to be typical of younger children and correlated with a better prognosis. We studied 21 patients aged 4-20 years (mean age 10 y 6 m) with this syndrome, with a clinical and EEG follow-up of 1-10 years (mean; 4 y 9 m). In 6 patients, EEG abnormalities fluctuated over time and sometimes were present only in the 24 hours following a seizure (3 patients) or, on the contrary, appeared 3-9 months after the first seizure (3 patients). Such fluctuations, which occured in an age range (3-11 years) in which the disease is active, could not be attributed to drugs and were found in patients with particularly benign prognosis. 5 of whom had the ictal pattern of versive seizures with vomiting. At least in some cases of idiopathic occipital epilepsy, the overall clinical criterion, seizure, semiology and background EEG are sufficient for a diagnostic suspicion and the 'occipital paroxysms' are an accessory element. Inclusion of only patients with EEG paroxysms could have caused an underestimation of prevalence, as well as the selection of patients with a greater number of seizures, in the series reported to date.