Tai Chi for Patients with Parkinson's Disease

To the Editor: The article by Li et al. (Feb. 9 issue)¹ reported that tai chi was successful in improving various functional outcomes in patients with mild-to-moderate Parkinson's disease, as compared with conventional physical exercises (resistance training and stretching). However, that success might be due to placebo effects rather than to the specific efficacy of tai chi itself. Since this study did not use a double-blind study protocol, participants were aware of their intervention assignments, possibly allowing their beliefs and expectations to bias treatment outcomes. Indeed, Parkinson's disease is one of a number of conditions that are particularly subject to . . .