Advanced Clinical Interpretation of the WAIS-IV and WMS-IV: Prevalence of Low Scores Varies by Level of Intelligence and Years of Education
ABSTRACT Clinicians can use the base rates of low scores in healthy people to reduce the likelihood of misdiagnosing cognitive impairment. In the present study, base rates were developed for the Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV) and Wechsler Memory Scale-Fourth Edition (WMS-IV) using 900 healthy adults and validated on 28 patients with moderate or severe traumatic brain injuries (TBIs). Results indicated that healthy people obtain some low scores on the WAIS-IV/WMS-IV, with prevalence rates increasing with fewer years of education and lower predicted intelligence. When applying the base rates information to the clinical sample, the TBI patients were 13 times more likely to be identified as having a low cognitive profile compared with the controls. Using the base rates information is a psychometrically advanced method for establishing criteria to determine low cognitive abilities on the WAIS-IV/WMS-IV.
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- "ith and without cognitive impairment ( Brooks et al . , 2011 ) . Convergent validity was supported by our data . Furthermore , this study is one of the first to highlight group differences between com - plicated mild / moderate and severe TBI using the WMS ; most previous WMS – II / WMS – IV work in TBI has focused on only moderate or severe TBI ( Brooks et al . , 2011 ; Langeluddecke & Lucas , 2005 ; Skandsen et al . , 2010 ; Walker , Batchelor , Shores , & Jones , 2009 ) , has not distinguished between mild and complicated mild TBI ( Fisher et al . , 2000 ; West et al . , 2011 ) , or has not distinguished complicated mild TBI from other TBI groups ( i . e . , only exam - ined TBI relative to control"
ABSTRACT: This study was designed to examine the construct validity of the Wechsler Memory Scale-Fourth Edition (WMS-IV) in individuals with traumatic brain injury (TBI). One hundred individuals with TBI (n = 35 complicated mild/moderate TBI; n = 65 severe TBI) and 100 matched controls from the WMS-IV normative dataset completed the WMS-IV. Multivariate analyses indicated that severe TBI participants had poorer performance than matched controls on all index scores and subtests. Individuals with complicated mild/moderate TBI performed more poorly than controls on all index scores, as well as on tests of visual memory (Designs I and II; Visual Reproduction I and II) and visual working memory (Spatial Addition; Symbol Span), but not on auditory verbal memory tests (Logical Memory I and II; Verbal Paired Associates I and II). After controlling for time since injury, severe TBI participants had significantly lower scores than the complicated mild/moderate TBI on 4 of the 5 WMS-IV index scores (Auditory Memory, Visual Memory, Immediate Memory, Delayed Memory) and 4 of the 10 WMS-IV subtests (Designs I and II, Verbal Pairs II, Logical Memory II). Effect sizes for index and subtest scores were generally moderate for the complicated mild/moderate group and moderate-to-large for the severe TBI group. Findings provide support for the construct validity of the WMS-IV in individuals with TBI.Journal of Clinical and Experimental Neuropsychology 09/2013; 35(9). DOI:10.1080/13803395.2013.833178 · 2.08 Impact Factor
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ABSTRACT: The frequencies of differences between highest and lowest subtest scores as a function of highest subtest score (relative scatter), are reported for the standardization sample of the Wechsler Adult Intelligence Scale-IV (WAIS-IV). Large differences between highest and lowest subtest scores were common. The degree of relative scatter was related to the height of the highest subtest score. For the 10 core WAIS-IV subtests, the correlation between the level of the highest subtest score and the amount of scatter was r = .62; for all 15 subtests the correlation was. 63. The level of the highest subtest score was more strongly related to scatter than was Full Scale IQ. Clinical implications for inferring cognitive impairment and estimating premorbid abilities are discussed. When considering the possibility of acquired cognitive impairment, we recommend caution in the interpretation of subtest score differences.The Clinical Neuropsychologist 01/2011; 25(1):62-71. DOI:10.1080/13854046.2010.533195 · 1.72 Impact Factor
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ABSTRACT: Knowing the prevalence of low neurocognitive scores for the WISC-IV Canadian normative sample (WISC-IV(CDN)) is an important supplement for clinical interpretation of test performance. On the WISC-IV(CDN), it is uncommon for children and adolescents to have 4 or more subtest scores or 2 or more Index scores ≤ 9th percentile when all scores on the battery are considered simultaneously. As the level of the child's intelligence increases or the number of years of parental education increases, the prevalence of low scores decreases. These results are consistent with existing studies of the base rates of low scores in children and adolescents on pediatric cognitive batteries, including the WISC-IV American normative sample. Tables provided are ready for clinical use.Child Neuropsychology 05/2011; 17(3):281-9. DOI:10.1080/09297049.2010.537255 · 2.42 Impact Factor