title: Utility of the Neurobehavioral Symptom Inventory Validity-10 index to detect symptom exaggeration: An analogue simulation study.
abstract: The Neurobehavioral Symptom Inventory (NSI) has been recommended by the interagency Traumatic Brain Injury (TBI) Outcome Workgroup as an outcome measure for TBI research. A new symptom exaggeration index-the NSI Validity-10-can be calculated from its items, but its utility has not been evaluated in a malingering simulation study. Data from a prior analogue study were reanalyzed to examine the NSI Validity-10 test properties. The data were from a sample of 85 Australian undergraduate students. A battery of measures was completed under 1 of 3 experimental conditions: control (i.e., honest responding, n = 24), feign postconcussional disorder (PCD; n = 29), and feign posttraumatic stress disorder (PTSD; n = 32). Participants who feigned PTSD or PCD had significantly higher scores on the NSI Validity-10 compared with controls. There were minimal differences between the 2 feigning groups. Using the combined data from the feigning groups and assuming a 35% symptom exaggeration base rate, the optimal NSI Validity-10 cutoff score was ≥10. This cutoff score identified "probable exaggeration" (sensitivity = .75, specificity = 1.0, positive predictive power = 1.0, negative predictive power = .88). Diagnostic efficiency statistics for 25% and 45% base rates were also generated. The cutoff score identified in this study is lower than previously reported. Its properties are promising, but its usage requires careful consideration.
authors.affiliation: a Clinical Neuropsychology Research Group, School of Psychology and Counselling , Queensland University of Technology , Brisbane , Australia.|b Institute of Health and Biomedical Innovation , Queensland University of Technology , Brisbane , Australia.
authors.forename: Karen A
authors.initials: KA
authors.lastname: Sullivan
authors.affiliation: c Defense and Veterans Brain Injury Center , Bethesda , Maryland , USA.|d Walter Reed National Military Medical Center , Bethesda , Maryland , USA.|e Department of Psychiatry , University of British Columbia , Vancouver , British Columbia , Canada.
authors.forename: Rael T
authors.initials: RT
authors.lastname: Lange
authors.affiliation: a Clinical Neuropsychology Research Group, School of Psychology and Counselling , Queensland University of Technology , Brisbane , Australia.|b Institute of Health and Biomedical Innovation , Queensland University of Technology , Brisbane , Australia.
authors.forename: Shannon L
authors.initials: SL
authors.lastname: Edmed
mesh_terms: D005260:Female; D006801:Humans; D008297:Male; D008306:Malingering / Q000175:diagnosis*; D009483:Neuropsychological Tests / Q000592:standards; D016544:Patient Simulation; D038223:Post-Concussion Syndrome / Q000175:diagnosis*; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D013313:Stress Disorders, Post-Traumatic / Q000175:diagnosis*; D055815:Young Adult
keywords: Diagnostic efficiency, Neurobehavioral Symptom Inventory; sensitivity; specificity; symptom exaggeration