Objective: Children have been found to give non-credible performances on neuropsychological evaluations and using Symptom Validity Tests (SVT) can help identify such cases. Results of neuropsychological tests are used to decide appropriate interventions and compensation, but it is necessary for maximum effort to be exerted for the test to be reliable and useful in determining next steps. This study assessed the relationship between non-credible performance on the Reliable Digit Span (RDS) and traumatic brain injury (TBI) and ADHD diagnoses in a pediatric clinical sample. It was hypothesized that those with a diagnosis of TBI would have a higher rate of non-credible performance compared to ADHD, consistent with prior research and thought to originate with increased motivation for functional deficit (Kirkwood, 2015)
Participants and Methods: RDS test scores from 200 pediatric clients previously referred to neuropsychological testing agencies in the northeast were collected from private practitioners. RDS scores from those with ADHD (n = 71) and TBI (n = 14) were analyzed to determine mean differences and rate of non-credible performance using a ≤ 6 cutoff score (Kirkwood, 2011).
Results: Preliminary results show that there was a significant difference (p = 0.03) in RDS performance between those with a diagnosis of TBI and ADHD, with TBI patients having a higher RDS score (M = 8.64) than those with a diagnosis of ADHD (M = 7.46). That is, 21% and 24% of participants, respectively, gave potentially non-credible RDS performances.
Conclusion: There are differences in the rate of credible performance on RDS across diagnoses in a pediatric clinical sample. Unexpectedly the results support the null hypothesis, but help to emphasize the importance of examining SVTs, like RDS, when conducting neuropsychological exams with children. Additional research is needed to clarify whether this finding persists with improved methodology (e.g., balanced sample sizes, clarified diagnoses, etc.)