Wald I, Stomma D
Psychiatr Neurol Med Psychol Beih. 1968;8-9:191-8.
In 490 Polish school districts 260 heavily imbecile children (I.Q. from 0 to 49), i.e., 0.30 percent of all children aged 5 to 15, among them 151 boys and 109 girls, were found by twenty teams composed of neuropsychiatrists, psychologists, and statisticians. The Langdon-Down syndrome was found in 39 cases (0.51 per thousand). 40.7 percent of the children had brothers and sisters that were weak-minded or afflicted with other psychic disorders. For 93 children it was possible to establish birth asphyxia. The proportion of children who because of imbecility are unable to attend normal schools amounts to 2.0 percent.
在490个波兰学区中，由神经精神病学家、心理学家和统计学家组成的20个团队发现了260名重度低能儿童（智商在0至49之间），即5至15岁所有儿童的0.30%，其中男孩151名，女孩109名。发现39例（每千分之0.51）患有朗顿 - 唐综合征。40.7%的儿童有智力低下或患有其他精神障碍的兄弟姐妹。对于93名儿童，可以确定存在出生窒息情况。因低能而无法进入正常学校就读的儿童比例为2.0%。
