A pilot study on the adequacy of the TOMM in detecting invalid performance in patients with substance use disorders

Classification accuracy and resistance to coaching of the Spanish version of the Inventory of Problems-29 and the Inventory of Problems-Memory: A simulation study with mTBI patients

Objective: The present study aims to evaluate the classification accuracy and resistance to coaching of the Inventory of Problems-29 (IOP-29) and the IOP-Memory (IOP-M) with a Spanish sample of patients diagnosed with mild traumatic brain injury (mTBI) and healthy participants instructed to feign. Method: Using a simulation design, 37 outpatients with mTBI (clinical control group) and 213 non-clinical instructed feigners under several coaching conditions completed the Spanish versions of the IOP-29, IOP-M, Structured Inventory of Malingered Symptomatology, and Rivermead Post Concussion Symptoms Questionnaire. Results: The IOP-29 discriminated well between clinical patients and instructed feigners, with an excellent classification accuracy for the recommended cutoff score (FDS ≥ .50; sensitivity = 87.10% for coached group and 89.09% for uncoached; specificity = 95.12%). The IOP-M also showed an excellent classification accuracy (cutoff ≤ 29; sensitivity = 87.27% for coached group and 93.55% for uncoached; specificity = 97.56%). Both instruments proved to be resistant to symptom information coaching and performance warnings. Conclusions: The results confirm that both of the IOP measures offer a similarly valid but different perspective compared to SIMS when assessing the credibility of symptoms of mTBI. The encouraging findings indicate that both tests are a valuable addition to the symptom validity practices of forensic professionals. Additional research in multiple contexts and with diverse conditions is warranted.

Performance Validity Test Failure in the Clinical Population: A Systematic Review and Meta-Analysis of Prevalence Rates

Performance validity tests (PVTs) are used to measure the validity of the obtained neuropsychological test data. However, when an individual fails a PVT, the likelihood that failure truly reflects invalid performance (i.e., the positive predictive value) depends on the base rate in the context in which the assessment takes place. Therefore, accurate base rate information is needed to guide interpretation of PVT performance. This systematic review and meta-analysis examined the base rate of PVT failure in the clinical population (PROSPERO number: CRD42020164128). PubMed/MEDLINE, Web of Science, and PsychINFO were searched to identify articles published up to November 5, 2021. Main eligibility criteria were a clinical evaluation context and utilization of stand-alone and well-validated PVTs. Of the 457 articles scrutinized for eligibility, 47 were selected for systematic review and meta-analyses. Pooled base rate of PVT failure for all included studies was 16%, 95% CI [14, 19]. High heterogeneity existed among these studies (Cochran's Q = 697.97, p < .001; I2 = 91%; τ2 = 0.08). Subgroup analysis indicated that pooled PVT failure rates varied across clinical context, presence of external incentives, clinical diagnosis, and utilized PVT. Our findings can be used for calculating clinically applied statistics (i.e., positive and negative predictive values, and likelihood ratios) to increase the diagnostic accuracy of performance validity determination in clinical evaluation. Future research is necessary with more detailed recruitment procedures and sample descriptions to further improve the accuracy of the base rate of PVT failure in clinical practice.

Profile of Embedded Validity Indicators in Criminal Defendants with Verified Valid Neuropsychological Test Performance

Objective

Few studies have examined the use of embedded validity indicators (EVIs) in criminal-forensic practice settings, where judgements regarding performance validity can carry severe consequences for the individual and society. This study sought to examine how various EVIs perform in criminal defendant populations, and determine relationships between EVI scores and intrapersonal variables thought to influence performance validity.

Method

Performance on 16 empirically established EVI cutoffs were examined in a sample of 164 criminal defendants with valid performance who were referred for forensic neuropsychological evaluation. Subsequent analyses examined the relationship between EVI scores and intrapersonal variables in 83 of these defendants.

Results

Half of the EVIs (within the Wechsler Adult Intelligence Scale Digit Span Total, Conners’ Continuous Performance Test Commissions, Wechsler Memory Scale Logical Memory I and II, Controlled Oral Word Association Test, Trail Making Test Part B, and Stroop Word and Color) performed as intended in this sample. The EVIs that did not perform as intended were significantly influenced by relevant intrapersonal variables, including below-average intellectual functioning and history of moderate–severe traumatic brain injury and neurodevelopmental disorder.

Conclusions

This study identifies multiple EVIs appropriate for use in criminal-forensic settings. However, based on these findings, practitioners may wish to be selective in choosing and interpreting EVIs for forensic evaluations of criminal court defendants.

Symptom and Performance Validity Assessment in European Countries: an Update

In 2013, a special issue of the Spanish journal Clínica y Salud published a review on symptom and performance validity assessment in European countries (Merten et al. in Clínica y Salud, 24(3), 129–138, 2013). At that time, developments were judged to be in their infancy in many countries, with major publication activities stemming from only four countries: Spain, The Netherlands, Great Britain, and Germany. As an introduction to a special issue of Psychological Injury and Law, this is an updated report of developments during the last 10 years. In that period of time, research activities have reached a level where it is difficult to follow all developments; some validity measures were newly developed, others were adapted for European languages, and validity assessment has found a much stronger place in real-world evaluation contexts. Next to an update from the four nations mentioned above, reports are now given from Austria, Italy, and Switzerland, too.