[Variability of normal grapho-elements and the assessment of abnormal grapho-elements in the EEG of clinically healthy test persons]. / Zur Variabilität normaler Wertung abnormer Graphoelemente im EEG klinisch gesunder Probanden.

The percentage pattern and topical distribution of alpha, beta, theta and delta waves, the occipital voltage level asymmetry of the alpha waves and the frequency of temporal functional disorders were studied in 100 17-year-olds, 273 male test persons of various age and 6,000 healthy persons. The results indicated that 1/4--1/8 of the test section is precentrally taken up by theta waves in the E.E.G. of healthy 17-year-olds. Random sampling on a larger scale shows that left occipital alpha wave domination is just as frequent as on the right; voltage level symmetry occurs only in 13--23 per cent of all cases. Three per cent of the clinically healthy persons showed local temporal E.E.G. anomalies which were on the left in 96 per cent of the cases. Attention is drawn to possible consequences with regard to nomenclature, evaluation and diagnostic assessment.