[Idiopathic partial epilepsy with occipital paroxysms].
BACKGROUND
The syndrome of idiopathic partial epilepsy with occipital paroxysms in the electroencephalogram (EEG) shows a considerable clinical and prognostic heterogeneity. The semiology of seizures varies considerably among patients and its hallmark, occipital paroxysms blocked by eye opening, may appear in other idiopathic or symptomatic epilepsies of childhood and even in nonepileptic disorders, notably basilar artery migraine. To address these unresolved issues in children with this rare form of epilepsy, the present paper utilized a longitudinal approach and investigated the significance of electrophysiologic and clinical characteristics necessary for the diagnostic and prognostic evaluation during a long-term follow-up.


METHODS
Over a 9-year period all patients, aged 1-15 years, who showed occipital paroxysms in EEG recordings were included in this study. In addition, clinical correlates were available for all these patients. Neurological, psychiatric and other clinical examinations were done in all patients. Whenever indicated, the neuroimaging of the brain (computerized tomography and/or magnetic resonance) was performed to establish the symptomatic aetiology. The epileptic syndromes were determined according to criteria of the International classification. A detailed EEG analysis of all patients, performed during a 3-12 year follow-up period, included hyperventilation, photic stimulation and a thorough testing of visual reactivity with exclusion of central vision. The incidence of EEG characteristics in patients with various epileptic syndromes was compared and its significance for the differential diagnosis was tested by nonparametric statistical methods. The clinical semiology of epilepsy and/or other associated disorders and EEG findings were compared among the patients with idiopathic partial epilepsy and occipital paroxysms.


RESULTS
Occipital epileptiform paroxysms were recorded in EEGs of 76 children with various clinical diagnoses but only 58 patients had seizures. The incidence of epilepsy (39 patients or 51%) was slightly higher than that of various non-epileptic disorders (37 patients or 49%). Two types of these paroxysms were analyzed: reactive (appearing at exclusion of central vision and disappearing on eye opening) or unreactive (persisting in the above situations). The difference in incidence of seizures (in a total of 58 patients) depending on the types of paroxysms was not statistically significant. EEG characteristics in 25 patients with both reactive paroxysms and seizures were compared in relation to the aetiology of epileptic syndromes. Comparing EEG in various types of epilepsy with reactive paroxysms, the statistical analysis (using Fischer's exact test) established that slowed background activity was significantly more frequent in symptomatic partial epilepsy than in idiopathic syndromes. On the other hand, EEG normalization during the follow-up period was a rule in benign epilepsy with centro-temporal paroxysms and in childhood absence epilepsy, and it was significantly more frequent in idiopathic partial epilepsy with occipital paroxysms than in symptomatic partial epilepsy. However, EEG findings per se cound not differentiate idiopathic partial epilepsy with occipital paroxysms from other epileptic syndromes. Neither seizures semiology could distinguish between different forms of occipital lobe epilepsy. Therefore, a correct syndromic and aetiologic classification for each patient with occipital spike-wave paroxysms required the combined and thorough assessment integrating clinical examination, clinical neurophysiological analyses, and neuroimaging studies during the follow-up. Using all above methods during the follow-up of 11 patients with idiopathic partial epilepsy with occipital paroxysms (IPEOP) it was found that this syndrome had often a very favorable prognosis if characterized by rare, nocturnal seizures beginning in preschool age. (ABSTRACT TRUNCATED)
Martinović
Z
Z
Institute of Mental Health, Belgrade. martinovic@sezampro.yu
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D004569:Electroencephalography; D004828:Epilepsies, Partial / Q000175:diagnosis*; D006801:Humans; D007223:Infant; D009778:Occipital Lobe / Q000503:physiopathology