The Illusion of Understanding: A Randomized Controlled Trial of LLM-Generated Lay Summaries of Brain MRI Reports

The trial enrolled 2,727 adult participants from the ComPaRe e-cohort and randomly assigned them to receive brain MRI reports either with or without an accompanying LLM-generated lay summary. Outcome measures included objective comprehension via specific questions and subjective comprehension such as self-rated understanding. The title 'The Illusion of Understanding' hints that lay summaries may inflate patients' confidence without actually improving measurable understanding. While the full results are yet to be published, the study raises important questions about how AI tools should be deployed in patient communication. Future work will likely need to determine whether LLM-generated summaries can be refined to genuinely improve comprehension rather than merely appear helpful.