Explore thyself: is it time for metacognition screening in clinical trials?

Participant self-report has become increasingly important in the design of clinical trials for Parkinson's Disease (PD), resonating with the general sense that a person's account of their experience should be a prime consideration in evaluating the effects of therapeutics. Typical study designs look to minimize the effects of comorbidities like substantial behavioral or cognitive disturbances that are expected to put accurate self-report at risk. However, little attention has been paid to the anticipated or actual ability of otherwise eligible PD study participants to accurately convey their experiences during participation. Metacognition, the ability to identify and reflect on one's thought processes and output, would seem to be instrumental for the careful evaluation of therapeutics using self-report but is not directly assessed during screening for clinical studies. Evidence suggests metacognition may be impaired in participants expected to be enrolled, suggesting the assessment of metacognitive ability during screening or even study conduct may be a worthwhile evolution in study design. Future directions include modeling performance of participants with a range of metacognitive capabilities to understand its influence on outcomes in both active and placebo groups, and possibly simple tools or tests to assess study candidates at risk for poor metacognitive performance in trials that prioritize self-report.