Studies in Mental

An aetiological study of mentally handicapped children in Edinburgh has provided an opportunity for assessing the prevalence of mental handicap in this area and the distribution of handicapped children by severity of defect and clinical type. A definite cause of mental handicap is found in only a minority of cases. Nevertheless, any aetiological investigation must begin with an attempt to classify patients by clinical condition, since associations of possible aetiological significance are likely to differ for those having subnormal intelligence only and those having different neurological or physical abnormalities in addition to subnormal intelligence. In this study the term 'mentally handicapped' is applied to children who are considered unsuitable for education in ordinary schools primarily on account of subnormal intelligence (i.e. estimated intelligence quotients of less than 70), but not to dull and backward children who are educationally retarded and may, in certain circumstances, be ineducable in the normal school system.