http://www.nejm.org/doi/full/10.1056/NEJMoa1107911

Tai Chi and Postural Stability in Patients with Parkinson's Disease
Fuzhong Li, Ph.D., Peter Harmer, Ph.D., M.P.H., Kathleen Fitzgerald, M.D., Elizabeth Eckstrom, M.D., M.P.H., Ronald Stock, M.D., Johnny Galver, P.T., Gianni Maddalozzo, Ph.D., and Sara S. Batya, M.D.
N Engl J Med 2012; 366:511-519February 9, 2012
BACKGROUND
Patients with Parkinson's disease have substantially impaired balance, leading to diminished functional ability and an increased risk of falling. Although exercise is routinely encouraged by health care providers, few programs have been proven effective.
METHODS
We conducted a randomized, controlled trial to determine whether a tailored tai chi program could improve postural control in patients with idiopathic Parkinson's disease. We randomly assigned 195 patients with stage 1 to 4 disease on the Hoehn and Yahr staging scale (which ranges from 1 to 5, with higher stages indicating more severe disease) to one of three groups: tai chi, resistance training, or stretching. The patients participated in 60-minute exercise sessions twice weekly for 24 weeks. The primary outcomes were changes from baseline in the limits-of-stability test (maximum excursion and directional control; range, 0 to 100%). Secondary outcomes included measures of gait and strength, scores on functional-reach and timed up-and-go tests, motor scores on the Unified Parkinson's Disease Rating Scale, and number of falls.
RESULTS
The tai chi group performed consistently better than the resistance-training and stretching groups in maximum excursion (between-group difference in the change from baseline, 5.55 percentage points; 95% confidence interval [CI], 1.12 to 9.97; and 11.98 percentage points; 95% CI, 7.21 to 16.74, respectively) and in directional control (10.45 percentage points; 95% CI, 3.89 to 17.00; and 11.38 percentage points; 95% CI, 5.50 to 17.27, respectively). The tai chi group also performed better than the stretching group in all secondary outcomes and outperformed the resistance-training group in stride length and functional reach. Tai chi lowered the incidence of falls as compared with stretching but not as compared with resistance training. The effects of tai chi training were maintained at 3 months after the intervention. No serious adverse events were observed.
CONCLUSIONS
Tai chi training appears to reduce balance impairments in patients with mild-to-moderate Parkinson's disease, with additional benefits of improved functional capacity and reduced falls. (Funded by the National Institute of Neurological Disorders and Stroke; ClinicalTrials.gov number, NCT00611481.)
Supported by a grant (NS047130) from the National Institute of Neurological Disorders and Stroke.
Disclosure forms provided by the authors are available with the full text of this article at NEJM.org.
No potential conflict of interest relevant to this article was reported.
We thank all the study participants (in Eugene, Corvallis, Salem, and Portland) for their support and dedication to this research project; the neurologists for providing medical clearance and Parkinson's disease stage diagnoses for their participating patients; the project instructors (Vicki Anderson, Denise Thomas-Morrow, Don Hildenbrand, Brian McCall, James Lusk, Nancy Nelson, Teena Hall, Machiko Shirai, and Julie Tye); the research assistants (Debbie Blanchard, Kristen Briggs, Ruben Guzman, Daehan Kim, Lisa Marion, Arissa Fitch-Martin, Kimber Mattox, Julia Mazur, Donna McElroy, Jordyn Smith, and Rachel Tsolinas); the physical therapists (Andrea Serdar, Jeff Schlimgen, Jennifer Wilhelm, Ryan Rockwood, and Connie Amos at Oregon Health and Science University); the study data analyst, Shanshan Wang; Kathryn Madden and the members of the institutional review board at the Oregon Research Institute for their careful scrutiny of the study protocol; and Ron Renchler for proofreading earlier drafts of the manuscript.
SOURCE INFORMATION

From the Oregon Research Institute (F.L.), the Oregon Medical Group (K.F.), and the PeaceHealth Medical Group–Oregon (R.S.) — all in Eugene; Willamette University (P.H.) and BPM Physical Therapy Center (J.G.) — both in Salem, OR; Oregon Health and Science University, Portland (E.E.); Oregon State University, Corvallis (G.M.); and Oregon Neurology Associates, Springfield (S.S.B.).
Address reprint requests to Dr. Li at the Oregon Research Institute, 1715 Franklin Blvd., Eugene, OR 97403, or at fuzhongl@ori.org.