Discrepancy between predicted and obtained WAIS–R IQ scores discriminates between traumatic brain injury and insufficient effort.

Abstract

This study examines how well the discrepancy between predicted and obtained Wechsler Adult Intelligence Scale--Revised (WAIS-R) scores discriminate between insufficient effort (IE) and traumatic brain injury (TBI). The 27 IE patients performed significantly more poorly on the WAIS-R than the 48 moderate-severe TBI patients. Premorbid IQs were calculated with formulae that use demographics (Barona Index) or demographics and WAIS-R performance (Best-3 and the Oklahoma Premorbid Intelligence Estimation). Predictions were similar on the Barona, but IE patients' predicted IQs were lower than TBIs for measures with a performance component. IE patients demonstrated a greater discrepancy score (i.e., predicted IQ--obtained IQ) than TBIs; variable levels of sensitivity and specificity were obtained when discriminate functions were developed on these scores. The potential advantage of using discrepancy scores versus performance-based measures to detect insufficient effort is discussed.

WAIS-R Factor Structure in Alzheimer's Disease Patients: A Comparison of Alternative Models and an Assessment of Their Generalizability.

“…Many clinicians continue to use the WAIS-R (Camara et al, 2000; Tulsky & Ledbetter, 2000). Given the wealth of research evidence amassed on it, the WAIS-R continues to be critical in forensic settings as well (e.g., Demakis et al, 2001). Moreover, WAIS-R normative data are available for individuals aged 56–97 years (Ivnik et al, 1992), whereas the age ceiling of the WAIS-III is 89 years.…”

Psychological Disturbance, Incomplete Effort, and Compensation-Seeking Status as Predictors of Neuropsychological Test Performance in Head Injury

“…Furthermore, such studies suggest even higher base-rates of probable malingering, at 40% or above (Greiffenstein, Baker, & Gola, 1994;Grote et al, 2000;Larabee, 2003;Meyers & Volbrecht, 1998). These studies find that persons exhibiting incomplete effort not only obtain lower scores, but produce an atypical pattern of performance on a number of NP tests including the Wechsler Adult Intelligence Scale -Revised (WAIS-R; Demakis, Sweet, Sawyer, Moulthrop, Nies, & Clingerman, 2001;Millis et al, 1998;Mittenberg, Theroux-Fichera, Zielinski, & Heilbronner, 1995), Wechsler Memory Scale -Revised (WMS-R; Iverson & Franzen, 1996;Mittenberg, Azrin, Millsaps, & Heilbronner, 1993), Halstead-Reitan Neuropsychological Battery (HRB;McKinzey & Russell, 1997), and the Memory Assessment Scales (MAS; Beetar & Williams, 1995;Ross et al, 2004). Most recently, Green, Rohling, Lees-Haley, and Allen (2001) examined incomplete effort in a large heterogeneous sample of neuropsychological referrals.…”

The Wechsler Adult Intelligence Scale—III and Malingering in Traumatic Brain Injury

“…Approaches to studying and detecting malingering on the WAIS include the following: (a) group comparisons of IQ, index, and individual standardized subtest scores in various clinical populations (Etherton, Bianchini, Ciota, Heinly, & Greve, 2006;Iverson & Tulsky, 2003;Johnstone & Cooke, 2003;Langeluddecke & Lucas, 2003;Loring, Lee, & Meador, 2005;Trueblood, 1994); (b) examination of discrepancy scores between predicted and obtained IQ scores (Demakis et al, 2001;Greve, Lotz, & Bianchini, 2008;Trueblood, 1994); (c) examining difference scores between agecorrected scaled scores on certain subtests, specifically Vocabulary and Digit Span (Iverson & Tulsky, 2003;Miller, Ryan, Carruthers, & Cluff, 2004;Mittenberg et al, 1995;Mittenberg et al, 2001); and (d) developing and analyzing discriminant function equations aimed directly at differentiating malingered from nonmalingered cognitive performance (Mittenberg et al, 1995;Mittenberg et al, 2001).…”