Litigation, Performance Validity Testing, and Treatment Outcomes in Adults with Mild Traumatic Brain Injury

Objective: To investigate whether involvement in litigation and performance validity test (PVT) failure predict adherence to treatment and treatment outcomes in adults with persistent symptoms after mild traumatic brain injury (mTBI). Setting: Outpatient concussion clinics in British Columbia, Canada. Participants were assessed at intake (average 12.9 weeks postinjury) and again following 3 to 4 months of rehabilitation. Participants: Adults who met the World Health Organization Neurotrauma Task Force definition of mTBI. Litigation status was known for 69 participants (n = 21 reported litigation), and 62 participants completed a PVT (n = 13 failed the Test of Memory Malingering) at clinic intake. Design: Secondary analysis of a clinical trial (ClinicalTrials.gov #NCT03972579). Main Measures: Outcomes included number of completed sessions, homework adherence, symptoms (Rivermead Post Concussion Symptoms Questionnaire), disability ratings (World Health Organization Disability Assessment Schedule 2.0), and patient-rated global impression of change. Results: We did not observe substantial differences in session and homework adherence associated with litigation or PVT failure. Disability and postconcussion symptoms generally improved with treatment. Involvement in litigation was associated with a smaller improvement in outcomes, particularly disability (B = 2.57, 95% confidence interval [CI] [0.25-4.89], P =.03) and patient-reported global impression of change (odds ratio [OR] = 4.19, 95% CI [1.40-12.57], P =.01). PVT failure was not associated with considerable differences in treatment outcomes. However, participants who failed the PVT had a higher rate of missing outcomes (31% vs 8%) and perceived somewhat less global improvement (OR = 3.47, 95% CI [0.86-14.04]; P =.08). Conclusion: Adults with mTBI who are in litigation or who failed PVTs tend to adhere to and improve following treatment. However, involvement in litigation may be associated with attenuated improvements, and pretreatment PVT failure may predict lower engagement in the treatment process.