title: A proposed method to estimate premorbid full scale intelligence quotient (FSIQ) for the Canadian Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV) using demographic and combined estimation procedures.
abstract: Establishing a comparison standard in neuropsychological assessment is crucial to determining change in function. There is no available method to estimate premorbid intellectual functioning for the Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV). The WISC-IV provided normative data for both American and Canadian children aged 6 to 16 years old. This study developed regression algorithms as a proposed method to estimate full-scale intelligence quotient (FSIQ) for the Canadian WISC-IV. Participants were the Canadian WISC-IV standardization sample (n = 1,100). The sample was randomly divided into two groups (development and validation groups). The development group was used to generate regression algorithms; 1 algorithm only included demographics, and 11 combined demographic variables with WISC-IV subtest raw scores. The algorithms accounted for 18% to 70% of the variance in FSIQ (standard error of estimate, SEE = 8.6 to 14.2). Estimated FSIQ significantly correlated with actual FSIQ (r = .30 to .80), and the majority of individual FSIQ estimates were within +/-10 points of actual FSIQ. The demographic-only algorithm was less accurate than algorithms combining demographic variables with subtest raw scores. The current algorithms yielded accurate estimates of current FSIQ for Canadian individuals aged 6-16 years old. The potential application of the algorithms to estimate premorbid FSIQ is reviewed. While promising, clinical validation of the algorithms in a sample of children and/or adolescents with known neurological dysfunction is needed to establish these algorithms as a premorbid estimation procedure.
authors.affiliation: Department of Neurology, University Hospitals of Cleveland and Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA. Michael.Schoenberg@uhhs.com
authors.forename: Mike R
authors.initials: MR
authors.lastname: Schoenberg
authors.forename: Rael T
authors.initials: RT
authors.lastname: Lange
authors.forename: Donald H
authors.initials: DH
authors.lastname: Saklofske
mesh_terms: D000293:Adolescent; D000367:Age Factors; D000465:Algorithms; D000704:Analysis of Variance; D002170:Canada; D016009:Chi-Square Distribution; D002648:Child; D003072:Cognition Disorders / Q000175:diagnosis*; D003710:Demography; D005260:Female; D006801:Humans; D007360:Intelligence / Q000502:physiology*; D008297:Male; D008960:Models, Psychological; D011237:Predictive Value of Tests; D012016:Reference Values; D014888:Wechsler Scales / Q000592:standards* / Q000706:statistics & numerical data