The need for attention to dose in mind-body interventions: lessons from t'ai chi clinical trials

The rise in popularity of complementary and alternative medicine (CAM) in the United States has stimulated increasing interest in researching CAM. One challenge to this research is determining the optimal dose of a CAM intervention. T'ai Chi Chuan (TCC) has received considerable attention as a mind-body practice; however, it remains unclear exactly how much TCC practice is necessary to elicit a discernable effect.

In this review, we selected 19 studies and examined the variation in the number and length of training sessions. Secondary and tertiary aims include examining attendance rates for each intervention and the instructions given to participants regarding home-based practice. The degree to which investigators monitored participants' home-based practice was also examined.

In the intent-to-treat analyses, the median time of TCC practice was 2877 minutes intended for participants across the selected interventions. Fourteen (14) of the publications provided information about participant attendance in the original publication, 2 provided additional information through further author inquiry, and 3 commented on TCC practice outside of the structured class environment through author inquiry.

The data reported are inconsistent in reported attendance and home-based practice rates, making it difficult to speculate on the relationship between the amount of TCC and intervention effects. Further research could contribute to this area by determining the optimal dose of TCC instruction.