Objective: While the Neuropsychological Assessment Battery, Screening Module (S-NAB) is a commonly used cognitive screening measure, no composite embedded performance validity test (PVT) formula has yet been described within it. This study sought to empirically derive PVT formulas within the S-NAB using an analog simulation paradigm.
Method: Seventy-two university students (M age = 18.92) were randomly assigned to either an Asymptomatic (AS) or simulated mild traumatic brain injury (S-mTBI) group and were administered a neuropsychological test battery that included the S-NAB and standalone and embedded PVTs. The AS group was instructed to perform optimally, and the S-mTBI group received symptom and test coaching to help simulate mTBI-related impairment. Both groups received warnings regarding the presence of PVTs throughout the test battery.
Results: Groups showed significant differences (all ps < .001) on all S-NAB domain scores and PVTs. In the S-NAB, the Attention (S-ATT) and Executive Function (S-EXE) domains showed the largest effect sizes (Cohen's ds = 2.02 and 1.79, respectively). Seven raw scores from S-ATT and S-EXE subtests were entered as predictor variables in a direct logistic regression (LR). The model accurately classified 90.3% of cases. Two PVT formulas were described: (1) an exponentiated equation from LR results and (2) an arithmetic formula using four individually meaningful variables. Both formulas demonstrated outstanding discriminability between groups (AUCs = .96-.97) and yielded good classification statistics compared to other PVTs.
Conclusions: This study is the first to describe composite, embedded PVT formulas within the S-NAB. Implications, limitations, and appropriate future directions of inquiry are discussed.
Keywords: Performance validity; embedded validity test; mild traumatic brain injury; neuropsychological assessment battery; simulation study.