Enhanced detection of suboptimal effort in psychoeducational assessments for dyslexia.

Abstract

Objective: Although performance validity tests (PVTs) are routinely administered in neuropsychological evaluations, they are employed less frequently in assessments for specific learning disabilities such as dyslexia, likely due, at least in part, to the limited availability of PVTs to evaluate effort on measures of academic achievement. This is troubling, as previous research suggests that up to 24% of postsecondary students undergoing learning disability assessments produce noncredible test scores indicative of symptom exaggeration or low effort. This paper discusses normative data collected for the revised Dyslexia Assessment of Simulation or Honesty- Revised (DASH-R), a PVT developed specifically to identify symptom exaggeration or magnification during dyslexia testing. Method: We administered the DASH-R to three groups of students: honest responding controls (n = 48), students with documented dyslexia (n = 232), and students coached to simulate dyslexia (n = 42). Students were also administered measures of reading and processing speed. Results: DASH-R scores differentiated simulators from both honest responding controls and those with dyslexia. Further, ROC curve analysis showed that a composite feigning index score derived from the DASH-R could be used diagnostically to detect low effort; an optimal cut score of ≥4 on a seven-variable index yielded high specificity (≥98%) and good sensitivity (71%), with positive predictive accuracy of 86%. Creation of a 9-variable index that included errors on an additional reading test produced improved positive predictive accuracy to 96% while retaining excellent specificity (99%). Conclusions: The DASH-R appears to be a promising disability-specific measure for detecting feigned reading problems in young adults undergoing evaluations for dyslexia.