By Dónal P. O’Mathúna, PhD
Dr. O’Mathúna is a lecturer in Health Care Ethics, the School of Nursing, Dublin City University, Ireland; he reports no consultant, stockholder, speaker’s bureau, research, or other financial relationships with companies having ties to this field of study.
Pain management has received dramatically increased attention in recent years, as evidenced by the new Joint Commission on Accreditation of Healthcare Organizations (JCAHO) regulations.1 Pain is now considered “the fifth vital sign,” requiring regular assessment and appropriate intervention. In spite of this, misunderstanding about pain and pain management is common and much remains to be understood. This occurs in part because of the subjective nature of pain and individuals’ differences in their perception and tolerance of pain.
Many complementary and alternative therapies claim to reduce pain. They are often recommended in an effort to avoid pain medications’ side effects, which can include sedation, confusion, falls, and urinary incontinence.2 Relaxation techniques have become especially popular in the treatment and management of pain, especially chronic pain.3 Mind-body medicine in general is based on the assumption that the mind can be used to influence physical conditions. Guided imagery is one such technique that can easily be learned by most people.1 Before recommending it for patients with chronic pain, the evidence for its effectiveness should be reviewed.
The recent practice of guided imagery was developed and refined by Roberto Assagioli in a popular book published in 1980.4 In its most popular form, people are guided to focus on a favorite place or activity which they find comfortable and enjoyable. The focus can be on something real or something imagined. The guidance can come in the form of specific instructions from a person or a recording, or more generally in the form of relaxing music.5 Once in the relaxed setting, people are guided to focus on colors, scents, sounds, or other aspects of the scene which they are imagining to deepen the experience. This form of guided imagery is sometimes referred to as “pleasant imagery” in contrast to “attention imagery.”6 In the latter form of guided imagery, people are guided to visualize and objectify their pain and then to change or discard it.7
Mechanism of Action
Guided imagery is based upon the belief that one’s thinking and beliefs can powerfully impact one’s experience of pain.5 However, there are divergent opinions on whether it is best to focus on the pain or distract one’s attention from the painful stimuli.6 Adaptation theory suggests that if patients focus on pain it will decrease over time during therapy. On the other hand, hyper-vigilance theory suggests the opposite, that pain is increased as it is focused upon.6 The differences probably relate to diversity in both types of pain and people’s individual coping strategies.
Many anecdotal reports claim that guided imagery effectively reduces patients’ pain and anxiety.5 At the same time, little controlled research has been conducted to establish which strategies are objectively effective.3 A review of controlled studies of guided imagery prior to 1999 found “preliminary evidence” for its effectiveness in reducing pain and some other symptoms.8 The review also concluded that larger, better designed studies were needed.
One such study of chronic tension headaches enrolled 350 subjects, of which 260 completed the study.9 New patients at a headache clinic were given individualized headache therapy and assigned to either a guided imagery group or a control group. An audiotape provided guided imagery instructions over soothing music and subjects were instructed to listen to it daily for one month. Headache frequency and severity decreased for both groups, but the guided imagery group experienced significantly greater improvement (P = 0.004). Significant differences were also found for vitality and mental health measures in the Medical Outcomes Study Short Form (SF-36).
Another common form of headache pain is migraine. A study of 40 migraine sufferers randomly assigned them to receive guided imagery, biofeedback, both, or neither.10 The control group was connected to biofeedback equipment and encouraged to relax for the same length of time as the other groups. After six 20-minute sessions, no significant differences were found between any of the groups in frequency or duration of migraines, interference with activities, or analgesic usage. However, patients in the guided imagery group reported a significantly improved ability to cope with their pain (P < 0.05).
One controlled study compared the effectiveness of pleasant and attention guided imagery.6 Fifty-five women diagnosed with fibromyalgia pain were randomly assigned to one of three groups. One group received guidance in pleasant imagery (n = 17), another in attention imagery (n = 21), and a third received usual treatment (n = 17). After four weeks, the group visualizing peaceful and beautiful scenery had significantly improved pain ratings on a visual analog scale (VAS) compared to the control group (P < 0.005). The group using guided imagery to focus on pain did not differ from the control group (P > 0.05), and had increased pain ratings compared to the pleasant imagery group (P < 0.005).
A pilot study randomly assigned 28 older women with osteoarthritis and joint pain to two groups.11 The intervention consisted of listening for 10-15 minutes twice daily to an audiotape guiding subjects with pleasant imagery and progressive muscle relaxation. The control group consisted of standard care along with journaling, which was also required of the interven- tion group. After 12 weeks, pain scores and mobility difficulties were significantly reduced in the intervention group (both P < 0.001) with no change in the control group.
A controlled trial randomly assigned 44 patients with various forms of chronic pain to two groups.7 One group did not change their pain management strategies. The other group used a seven-minute guided imagery audiotape three times daily for four days. The instructions encouraged people to relax, to view their pain as an object, and then to change or discard the object. Each day all participants were interviewed about their pain. Their descriptions were classified into six categories: that pain is never-ending, relative, explainable, torment, restrictive, or changeable. Statistical analysis of changes was not carried out. However, clear improvements occurred with guided imagery. The number of people in the treatment group reporting pain as never-ending changed from 11 to 0, while in the control group it went from 10 to 15. Those reporting pain as changeable went from 4 to 11 in the guided imagery group compared with 5 to 2 in the control group. However, reports of pain as restrictive went from 8 to 0 with guided imagery, but also went from 5 to 1 in the control group. Differences in the other descriptors were less clear-cut.
Most studies of guided imagery for pain have focused on chronic pain. However, a pilot study was conducted with 13 men scheduled for knee or hip replacement surgery.2 In addition to usual preoperative and postoperative care, all subjects were given an audiotape. The intervention group’s tape contained music and guidance on developing pleasant and comfortable images while the control group’s tape contained only relaxing music. Participants were instructed to listen to the tape on the evening after surgery and twice daily until discharged. Statistical analysis was not conducted because of the small sample size. Differences were visible between the intervention and control groups in VAS pain scores (2.35 vs. 5.30, respectively), IV morphine use during the first four postoperative days (36.70 vs. 84.87 mg), and length of stay (9.29 vs. 14.83 days).
Most of the studies located by searching PubMed found guided imagery effective for reducing pain. No adverse effects were reported. However, many of the studies enrolled small numbers of subjects or were pilot studies. Some variation in outcomes was reported depending on the particular type of pain. Also, much remains unclear about guided imagery, including the preferred form of guidance, the best type of imagery, individual variation in responses, and the optimal frequency and duration of therapy. For example, in spite of a belief that better outcomes result from prolonged use of guided imagery, a 2004 review found no studies supporting this perceived relationship.12 The reviewer conducted a meta-analysis of 10 studies of varying duration and found increased effect size over the first 5-7 weeks, but decreased effect size at 18 weeks. Much remains to be understood about the precise way to carry out guided imagery.
Given the lack of adverse effects from guided imagery, and the relative ease and cost-effectiveness of its introduction, guided imagery can be recommended for patients with pain. Patients should be alerted to the variation found in some studies, both with individuals and types of pain, so that they are not led to have unrealistic expectations. Pain perception and management is complicated and should be individualized. The evidence to date warrants larger studies of guided imagery to determine how its outcomes can be optimized. As a nonpharmacological strategy for reducing pain, guided imagery should be included among the strategies made available to patients suffering pain, especially chronic pain.
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