[Neurophysiological activation and behavior during mental achievement. Comparative studies in healthy, minimally brain damage and mongoloid children].

A comparison of normal, mildly brain-injuried and mongoloid children. For psychophysiological investigations in young or mentally disturbed children a new methodical approach was developped. In children with minor nervous dysfunction (aged 6--8;3 years) and mongoloid children (5;6--11 years) as well as in younger and older normal children (3;9--5;5 resp. 5;6--7;6 years) the changes of EEG basic rhythm, heart rate and behaviour during defined mental work were observed. Each group consisted of 18 children. The physiological data were analyzed by computer. The main results are summarized in the following points: 1) The request of mental activity with increasing task difficulty causes increasing neurophysiological and behavioural activation up to an optimal value at the highest degree of individual efficiency. 2) Overstrain leads to a deterioration of activation and consecutively to a loss of motivation, especially in the handicapped children. 3) Alpha waves of the EEG can be unterstood as an index of selective stimulus inhibition or "concentration". In the normal children the amount of alpha waves during mental work was very significantly higher than in both the groups of the handicapped children. 4) Further differences in EEG, heart rate and behaviour between the 4 groups support the understanding of the psychic features in Down's syndrome and in the syndrome of minor nervous dysfunction at a physiological level.