Study designs of evaluations included in the review
Randomised controlled trials (RCTs) were eligible for inclusion.
Specific interventions included in the review
Studies of physiotherapy or (spinal) manipulation were eligible for inclusion. The included studies used a variety of different types of spinal manipulation (e.g. chiropractic spinal, connective tissue and osteopathic manipulation and CV4 technique) and physiotherapy (e.g. combinations of parafango, massage, ultrasound, relaxation techniques and cryotherapy). The control interventions included acupuncture, deep friction massage plus mobilisation, palpation, rest and placebo (low-power laser light).
Participants included in the review
Studies of adults (aged 18 years or more) with TTH were eligible for inclusion. Studies including patients with TTH and migraine were only included if they reported results separately for patients with TTH. The studies were not required to adhere to a classification system to diagnose TTH, but the diagnosis had to be based on at least some of the distinctive features of the condition.
Outcomes assessed in the review
The studies had to report at least one patient-rated outcome measure. The included studies used a variety of outcome measures, the most common of which were headache frequency, intensity and severity, headache index, use of medicines and electromyographic activity (EMG). The review assessed both short-term outcomes (6 to 8 weeks post-treatment) and long-term outcomes (outcomes reported closest to 16 weeks), as well as side-effects.
How were decisions on the relevance of primary studies made?
Two reviewers independently selected studies from full papers. Any disagreements on inclusions were resolved through discussion or through recourse to a third author, where necessary. The reviewers were not blinded to the authors, journal or institution.