Study designs of evaluations included in the review
Controlled trials were included.
Specific interventions included in the review
Trials of AT were included; one trial used AT in combination with visual imagery. Five studies featured no treatment control groups, whereas three studies compared AT with progressive relaxation, electrical stimulation or hypnosis. The application of the AT technique varied considerably among studies. The number of AT sessions offered to the participants varied from 1 to 12, and the duration varied from 30 to 90 minutes.
Participants included in the review
Healthy volunteers such as university students with no known medical condition, nursing students or sportsmen, were included. Two studies recruited patients from psychiatric institutes, whilst one recruited through newspaper articles and radio interviews. Gender of participants was reported in only 4 studies, mean age was reported in 4 studies, and an age range was reported in 1 study. Three studies failed to provide any clear information on participants' ages.
Outcomes assessed in the review
Reduction of stress and anxiety levels were measured in 4 of the 8 studies using Spielberger's State-Trait Anxiety Inventory. Other measurements were sickness absence records, electromyography, auditory feedback, cognitive-somatic anxiety questionnaire, mental health self-rating symptom scale, psychovegetative complaints and frequency of pain attacks.
How were decisions on the relevance of primary studies made?
The authors do not state how the papers were selected for the review, or how many of the authors performed the selection.