The WAIS-III General Ability Index (GAI; Tulsky, Saklofske, Wilkins, & Weiss, 2001) is a recently developed, 6-subtest measure of global intellectual functioning. However, clinical use of the GAI is currently limited by the absence of a method to estimate premorbid functioning as measured by this index. The purpose of this study was to develop regression equations to estimate GAI scores from de...

AIMS (1) To examine the relation between neurological soft signs and measures of cognition, coordination, and behaviour in mainstream schoolchildren. (2) To determine whether high soft sign scores may predict children with significant problems in other areas. METHODS A total of 169 children aged between 8 and 13 years from mainstream schools were assessed. They form part of a larger study int...

Field dependence and spatial ability are widely thought of as distinct psychological dimensions. We sought to evaluate the alternative hypothesis that these are, in fact, different labels for a common underlying dimension. A sample of 60 subjects was selected on the basis of scores on a test of spatial ability. These subjects completed two tests of field dependence--the Embedded Figures Test an...

A prospective study based on the U.S. National Collaborative Perinatal Project and using the Wechsler Intelligence Scale for Children (WISC) found lower test scores for the Coding subtest in preschizophrenic children than in their unaffected siblings. Using data on cognitive functioning in adolescence, the aim of the present prospective study was to examine whether low scores on Coding is assoc...

Accumulating evidence suggests that executive functions (EFs) are related to intelligence, despite neuropsychological results initially considered evidence of no such relation. However, findings that EFs are not unitary raise the issue of how intelligence relates to different EFs. This study examined the relations of fluid and crystallized intelligence and Wechsler Adult Intelligence Scale IQ t...

The reliability and factorial validity of the Wechsler Intelligence Scale for Children–Fifth Edition: Canadian (WISC-V) was investigated. The higher-order model preferred by Wechsler (2014b) contained five group factors but lacked discriminant validity. An alternative bifactor model with four group factors and one general factor, akin to the traditional Wechsler model, exhibited the best global...

The Processing Speed Index (PSI) was first introduced on the Wechsler Intelligence Scale, Third Edition (WISC-III; D. Wechsler, 1991), and little is known about its clinical significance. In a referred sample (N 980), children with neurological disorders (ADHD, autism, bipolar disorder, and LD) had mean PSI and Freedom from Distractibility Index (FDI) scores that were below the group mean IQ an...