[Motor developmental screening test for mental retardation: evaluations of sensitivity and specificity].

For the purpose of early detection and early habilitation for developmentally handicapped children, we started medical screening for pediatric neurological diseases among children in Sodegaura City, Chiba prefecture, since 1978. We calculated sensitivity, the rate of judging abnormal children to be abnormal, specificity, the rate of judging normal children to be normal and positive predictive values, the rate of judging abnormal children who have abnormal sign, of sitting alone at nine months of age whether an infant is MR or not. The sensitivity was 70.0%, the specificity was 98.3% and the positive predictive value was 26.5%, all of them were high rates. Therefore we conclude that children who can not sit alone until nine months of age are possibly mentally retarded and the capability of sitting alone or not at nine months of age is an useful screening test for the purpose of early detection of mentally retarded children.