Background: Diagnostics and care for people with intellectual disabilities (ID) and psychiatric disorders need to be improved. This can be done by using assessment instruments to routinely measure the nature and severity of psychiatric symptoms. Up until now, in the Netherlands, assessment measures are seldom used in the psychiatric care for this…

Background: Executive functioning (EF) is an important concept in cognitive psychology that has rarely been studied in people with intellectual disabilities (IDs). The aim of this study was to examine the validity of two test batteries and the structure of EF in this client group. Methods: We administered the children's version of the Behavioural…

Although it is well established that preterms as a group do poorly relative to their full-term peers on tests of global cognitive functioning, the basis for this relative deficiency is less understood. The present paper examines preterm deficits in core cognitive abilities and determines their role in mediating preterm/full-term differences in IQ.…

Background: Empirical studies of the structure of autism symptoms have challenged the three-domain model of impairment currently characterizing pervasive developmental disorders (PDD). The objective of this study was to assess the internal validity of the DSM as a conceptual model for describing PDD, while paying particular attention to certain…

The incremental validity of factor scores from the Wechlser Intelligence Scale for Children-III (WISC-III) in predicting scores on the Wechsler Individual Achievement Test (WIAT) was studied in 283 nonreferred children and 636 referred for evaluation. The Full Scale IQ of the WISC-III was the best predictor of WIAT achievement. (SLD)