[Electrophysiological study of children with various hereditary forms of mental retardation].

Nine children with syndromes of Albright, Coffin-Loury, Ullrich-Noonan, C. De Lange and brachyphalangia with prenatal cerebral affection and severe mental retardation have been examined. They entered group I. Four children with syndromes of Möbius, Christ-Siemens and LEOPARD with secondary retardation of cognitive activity comprised group II. In a case of Coffin-Loury and Albright syndromes electroencephalographic picture was similar to that for Martin-Bell syndrome. In the majority of the patients general changes in the EEG presented with local ones. Correlations between intra- and interhemispheric EEG parameters deviated from those of healthy children matched for age. A drastic prevalence of the left-handers and ambidexters in a primary whereas right-handers in a secondary cerebral disorder has been recorded.