CHILDREN WITH BENIGN FOCAL SHARP WAVES IN THE EEG - DEVELOPMENTAL DISORDERS AND EPILEPSY

Focal sharp waves (shw) in the childhood EEG with predominantly centro temporal localization are a diagnostic hallmark of idiopathic partial epilepsy and have been shown to be genetically determined. Absence of neurological and neuropsychological impairment was long considered to be a prerequisite for diagnosis. For years, this diagnostic paradigm o bscured the large phenotypic variability of genetically determined foc al shw. The purpose of the present review is to survey and critically evaluate the widely dispersed literature on this topic. Two main group s can be distinguished: Idiopathic partial epilepsies and specific dev elopmental disorders such as dysphasia, dyslexia etc. These conditions , however, do not represent clear-cut nosologic entities, but exhibit large symptomatic overlaps. In nonepileptic children, developmental di sabilities constitute the main symptoms, in epileptic children - at le ast in nonselected groups - they are an optional feature. Conversely, epileptic phenomena can dominate the clinical picture or be an optiona l symptom in developmentally disabled children. The wide spectrum of e pileptic and non-epileptic disorders probably represents the multifari ous clinical manifestations of a common widespread, genetically determ ined pathogenetic mechanism. The marked age-dependency of the EEG and clinical symptoms, and the almost regular disappearance of both at pub erty appear to justify the hypothesis of a hereditary impairment of br ain maturation. The large phenotypic variability can be explained by d ifferences in location and extent of the maturational disturbance as w ell as by the effect of additional genetic and environmental factors. The nature and cause of the hypothetical maturational disturbance are still unknown.