Digit Span-Related Performance Validity Indicators in Patients with Cognitive Impairment

Abstract

Neuropsychological evaluation is utilized to assess an individual’s pattern of performance and level of cognitive functioning compared to a predicted premorbid level of functioning. Evaluation is accomplished through administration of neuropsychological battery of tests, following a diagnostic interview and review of medical records. Assessment of performance validity (i.e., effort or motivation) must be considered throughout the evaluative process. Performance validity (i.e., effort) is the concept that the obtained performance reflected in a patient’s assessment profile is a true representation of that individual’s ability, thus impacting the neuropsychologist’s ability to interpret the obtained scores as being representative of their true cognitive functioning. While performance validity has been evaluated in many populations (Babikan, Boone, Lu & Arnold, 2006; Heinly, Greve, Bianchini, & Love, 2005; Greve et al., 2007), recent research has only briefly focused on the utility of effort indicators in the context of the performance of patients diagnosed with dementia (Kiewel, Wisdom, Bradshaw, Pastorek, & Strutt, 2012). The purpose of this retrospective review is to evaluate the efficacy of Digit Span-related performance as an indicator of poor effort in a clinical sample of patients diagnosed with either no, mild, or major neurocognitive impairment, ultimately identifying consistency between WAIS-IV Digit-Span related PVTs and if an individual’s characteristics are significant predictor variables when determining performance validity. A logistic regression was utilized to analyze data to determine if the WAIS-IV Digit Span related PVTs are consistently measuring performance or if the determination of valid vs invalid responding is influenced by factors other than performance.