Study Approval, Participant Criteria and Recruitment
The protocol and informed consent forms were reviewed and approved by the Institutional Review Board (IRB approval#: 03-12-063-01) at the University of California at Los Angeles (UCLA).
Inclusion criteria were as follows: adults between 20 and 65 years of age at time of trial with the ability to undertake 30 min of mild exercise a day, who were diagnosed with TTH [using International Headache Society (IHS) criteria (10
)] by a physician at the UCLA Center for East West Medicine (CEWM). Exclusion criteria were as follows: having any headache condition other than, or in addition to, TTH (e.g. migraine, cluster headaches, etc.); having previous practice of Tai Chi or Qi Gong (Qi Gong refers to all traditional Asian health practices involving what is thought to be the circulation of energy in pathways throughout the body, whereas Tai Chi is a martial art developed from Qi Gong practices and is considered a form of Qi Gong); significant comorbid illness that would be expected to prevent completion of the study; any additional conditions (e.g. severe hearing loss, respiratory, cardiovascular or neurological problems) that might interfere with the required intervention and evaluations; any acute intercurrent illness that might interfere with the interpretation of the study (e.g. influenza); and self-reported inability to commit to the intervention schedule.
Participants were volunteers recruited from the Los Angeles area who responded to advertisements circulated by the UCLA Department of Medicine and posted in local newspapers seeking adults with tension headaches wishing to receive free treatment. Interested participants were asked to telephone and were screened to determine eligibility. Informed consent was obtained during the first visit to the CEWM, where participants were then independently screened for recruitment criteria.
Out of 122 Potential Participants 47 Met All Recruitment Criteria and Were Randomized into Either the Control or Intervention Group
A total of 122 phone calls were received from potential participants (see ). Of these, 29 (24%) did not respond to follow-up contact, 4 (3%) were unwilling to provide eligibility information, 29 (24%) were deemed ineligible from phone interview and 9 (7%) potential participants were no longer interested in participation after hearing details of the study. After screening, 4 (3%) additional potential participants were deemed ineligible. It was determined that 47 (39%) participants met all recruitment criteria and were randomized into either the control group (n = 23) or intervention group (n = 24).
Thirty of the Forty-Seven Randomized Participants Completed the Study
After randomization, five participants declined to participate as a result of a time delay between recruitment and randomization, or due to conflicts with the intervention schedule. Hence, a total of 42 participants were randomized to the treatment (n = 21) or the control group (n = 21). During the course of intervention, an additional 8 participants dropped out of the treatment group and 4 participants dropped out of the control group, leaving 30 participants who completed the study (13 in the treatment group; 17 in the control group).
The Intervention Consisted of 15 Weeks of Bi-Weekly Instruction in the Yang Style Short Form of Tai Chi
Participants in the intervention group received bi-weekly sessions an hour in duration for 15 weeks. There were two cohorts for the intervention group to provide more flexibility to participants. Classes were taught at a local park distinct from the location of study assessment.
Subjects were taught the classical Yang style of Tai Chi short form. This 24 standardized movement form is the most widely practiced style of Tai Chi (4
). An instructor with over 20 years of experience in Tai Chi instruction and practice administered sessions.
Handouts were provided summarizing the Tai Chi movements, and a video of the form was provided to assist participants.
Improvement was Assessed with the Health-Related Quality-of-Life Measure SF-36v2 and the Headache Impact Measure HIT-6™
Health-related quality-of-life (HRQOL) was assessed with the SF-36v2, a generic measure that has been extensively used in both clinical and research settings (22
). The SF-36v2 measures eight domains of health as follows: general health perceptions (5 items); physical functioning (10 items); role limitations due to physical problems (4 items, role-physical); bodily pain (2 items); energy/fatigue (4 items); social functioning (2 items); role limitations due to emotional problems (3 items, role-emotional); and emotional well-being (5 items).
The HIT-6™ is a 6-item fixed-length, short-form version of the DYNHA®
Headache Impact Test designed to capture the effect of headache and its treatment on an individual's functional status and well-being. The items in HIT-6™ cover the content areas found in widely used measures of headache impact, including pain, ability to carry out usual activities, social functioning, energy/fatigue, cognitive functioning and psychological distress. HIT-6™ is useful both for screening and for monitoring change in disease impact (23
Assessment was performed before the first treatment session (post-randomization), at Weeks 5, 10 and 15 during the 15 week intervention period. Each participant received a mailing on the first day (Monday) of each assessment week containing all self-report measures with instructions, and was asked to return the assessments in an enclosed self-addressed stamped envelope by the end of the week. Participants were called on the second day (Tuesday) of each assessment week to verify that the mailing had been received. Participants were called on the fourth day (Thursday) and fifth day (Friday) of the week as a reminder. All outcome measures were held in a secure location at the CEWM in sealed envelopes until the completion of the intervention period.
An administrative assistant (in no other way connected with the study) was the only person given access to the data, and was responsible for entering all raw data into Microsoft excel for analysis. We evaluated the extent to which randomization was successful by comparing the age and gender of the treatment and control groups (). We computed t-tests to assess the statistical significance of the difference in changes in SF-36 scores and the HIT score between the treatment and control groups (). The 15 week follow-up data was used if available. If not available, the 10 week data was used. If still not available, the 5 week data was used. This approach allowed us to maximize the sample size for the analysis. There was too few observations at the individual follow-up intervals to justify a trend analysis.
Demographic characteristics of participants
Differences in changes in HRQOL and headache impact between treatment and control groups