Kwekkeboom, K.L., Wanta, B., & Bumpus, M. (2008). Individual difference variables and the effects of progressive muscle relaxation and analgesic imagery interventions on cancer pain. Journal of Pain and Symptom Management, 36, 604–615.doi: 10.1016/j.jpainsymman.2007.12.011
To assess, among hospitalized patients with cancer-related pain, responses to progressive muscle relaxation (PMR) and analgesic imagery, including the impact of these interventions on pain-related distress and perceived control over pain
To examine the influence of ability, outcome expectancy, previous experience, and concurrent symptoms on the effectiveness of the interventions
Scripts relating to "control conditions," PMR, and guided imagery interventions were recorded on a CD. The recorded voice was male, and the recording did not include music. The day 1 control recording consisted of identification of health team members, explanation of patient rights, and a description of various hospital services. The second control recording described exercise and other activities to maintain strength while hospitalized and presented issues for consideration in discharge planning. The PMR recording guided listeners in tensing and relaxing muscles in a series of 12 major muscle groups from head to feet. The analgesic, or guided imagery, recording asked listeners to scan their bodies to identify areas of pain and to imagine replacing pain with comforting sensations. Then the recording asked listeners to imagine putting their hand in an anesthetic fluid, feeling it go numb, and then transfer the numbness to painful areas of the body. All recordings were of similar length. Trials were done when current pain was rated 2–8 on a 10-point scale. Trials were delayed if patients had received an oral analgesic within one hour or an IV analgesic within 30 minutes. Patients with the option of patient-controlled analgesia were asked to refrain from increasing doses during the 15-minute trial and were maintained on basal continuous infusion. A control trial was the first trial done each day. If pain persisted at the end of the control trial, the research nurse continued with whichever experimental trial was assigned for that day. Two intervention trials were done each day, at least one hour apart. Patients completed pre- and post-trial ratings of pain intensity and related distress. For each outcome measured, scores were averaged across two control, two PMR, and two analgesic imagery trials. In cases where only one trial was completed, this score was used in analysis. Patients were randomly assigned to two different groups. In one group, PMR preceded imagery interventions; in the other, the sequence was reversed. All patients received the same control trials.
The study used a crossover design with control.
In only 50% of patients did PMR and guided imagery appear to have a more positive short-term effect on pain intensity, pain-related distress, and perceived control of pain than did simple distraction. Variables examined did not appear to influence the effects of PMR, but expectations and number of concurrent symptoms appeared to influence the effects of guided imagery.
PMR and analgesic imagery, facilitated by a recording on CD, might be helpful to some patients to reduce short-term pain intensity, decrease pain-related distress, and increase sense of control over pain. However, much more evidence is needed before investigators can draw firm conclusions. These interventions could be implemented easily in a hospital setting and do not appear to harm patients. They appear to be more effective for individuals with greater ability to imagine, greater expectations of effectiveness, and fewer additional symptoms. This fact might lead clinicians to identify that group of patients most likely to benefit from such interventions.