Performance validity in the dementia clinic: Specificity of validity tests when used individually and in aggregate across levels of cognitive impairment severity.

ABSTRACT

OBJECTIVE: This study examined the specificity of both individual PVTs and three different PVT batteries in individuals undergoing neuropsychological evaluation for dementia in order to establish both appropriate individual test cutoffs and multiple-PVT failure criterion. METHODS: Participants were 311 validly performing patients with no cognitive impairment (n = 24), mild cognitive impairment (MCI; n = 115), mild dementia (n = 122), or moderate dementia (n = 50). Cutoffs associated with ≥90% specificity were established for 11 individual PVTs across impairment severity groups. Aggregate false positive rates according to number of PVTs failed were examined for two 4-PVT batteries and one 7-PVT battery. One-way ANOVAs with post-hoc comparisons were conducted for each PVT. RESULTS: Performance on 9 of 11 PVTs significantly differed according to impairment severity. PVT cutoffs achieving ≥90% specificity also generally varied by group. For PVTs previously validated in non-dementia samples, slight adjustments from established cutoffs were generally required to maintain adequate specificity in MCI and mild dementia groups, with greater modifications required in the moderate dementia group. A criterion of ≥2 PVT failures resulted in ≥90% specificity in both 4-PVT batteries across groups. In the 7-PVT battery, adequate specificity was achieved with ≥2 failures in MCI and ≥3 failures in the mild dementia group. CONCLUSIONS: The incorporation and interpretation of several easily assimilated multiple-PVT batteries in dementia evaluations are explored. Additionally, data regarding individual PVT performance according to cognitive impairment severity are provided to aide validity assessment of both patients undergoing dementia evaluation and examinees who are less impaired.