[Detection and prevention of mental and motor disorders in childhood. 4. The group of children which were studied].

The authors submit basic data on a group of cca 11,000 children included in a research project Detection and reduction of sensory and motor disorders in childhood. The children were examined at time intervals fixed in advance (when care was initiated, during the 4th, 8th, 12th and 36th month of age). The reduction of the number of children in the course of three years, commonly encountered, is smaller than in the majority of longitudinal studies. The ratio of boys and girls corresponds to the ratio in the population and the distribution of data in the investigated regions is constant. In subsequent investigations the authors will submit eventually data from prenatal and postnatal investigations.