Pareidolias in idiopathic RBD—an author response letter to the Editorial “What the ‘man in the moon’ can tell us about the future of our brains”

In our original paper (1), we aimed to clarify the clinical significance of pareidolia in patients with idiopathic RBD. Prior to our work, Dr. Uchiyama and his coauthors from Professor Mori’s research group from Department of Behavioral Neurology and Cognitive Neuroscience, Tohoku University School of Medicine established a practical and useful test, the pareidolia test, for evoking pareidolic response (2), which is a surrogate marker of visual hallucination. We conducted the test in idiopathic RBD patients, in whom more than half of them showed pareidolias. Following the comments to pareidolia in idiopathic RBD in the Editorial “What the ‘man in the moon’ can tell us about the future of our brains” from Professor Birgit Högl, we gratefully continue to discuss this topic, which further highlights the potential need to clarify the clinical benefit of the phenomenon in idiopathic RBD in terms of prediction of future conversion to Lewy body diseases and pathological course.