I recently came across a whole range of papers about Tai Chi for health in The American Journal of Physical Medicine & Rehabilitation – all positive stuff and worth a read.
Subjects include :
Evaluating the Safety and Potential Use of A Weight-Bearing Exercise, Tai-Chi Chuan, for Rheumatoid Arthritis Patients
Also from Natural News a couple of pieces on Parkinsons:
and from Hindawi publishing a piece on Tai Chi for Patients with Schizophrenia: