Brief summary of evidence supporting the efficacy of biofeedback for phantom pain:
Several small studies summarized in Sherman (1996) have related the effectiveness of behavioral and medical treatments of phantom pain to underlying physiological correlates. When research on amputees demonstrated that decreased blood flow in the stump was related to increased burning phantom limb pain, peripheral vasodilators and temperature biofeedback were used to decrease the phantom pain. When increased muscle tension and spasms in the stump were related to episodes of cramping phantom pain, muscle relaxants and muscle tension biofeedback were used to control the pain.
Researchers found EMG biofeedback to be effective for thirteen of fourteen trials for cramping phantom pain. EMG biofeedback had minimal success with two and no success with ten of twelve trials for burning phantom pain. It had no success with eight trials of shocking phantom pain. Temperature biofeedback was ineffective for four trials of cramping phantom pain, was effective for six of seven trials with burning phantom pain, and had no success with three trials for shocking phantom pain. Nitroglycerine ointment (a topical vasodilator) was ineffective for one trial of cramping phantom pain and one of shocking phantom pain but successful for two trials of burning phantom pain.
Trental (a blood viscosity enhancer) was ineffective for two trials of cramping phantom pain and one of shocking phantom pain. Nifedipine (a systemic vasodilator) was effective for three trials of burning phantom pain but ineffective for one trial of cramping and two trials of shocking phantom pain. Flexeril (a muscle relaxant) was effective for two trials of cramping phantom pain but ineffective for one with shocking phantom pain. Indocin (an anti-inflammatory agent) was ineffective for two trials of cramping phantom pain. The overall conclusion from this investigation is that varying types of phantom pain respond virtually only to interventions which alter the underlying mechanisms.
Follow-up Durations: Only one study with significant follow-ups has been reported (Cf., review in Sherman, , Devor, Jones, Katz, Marbach, 1996). Use of EMG biofeedback combined with home use of progressive muscle relaxation exercises showed excellent success with six month to three year follow-up for fourteen of sixteen successive phantom pain patients.
Treatment Success vs. Learning to Control the Appropriate Physiological Parameter: The major difference between those patients in the above study who succeeded in learning to control their pain and those who did not was the ability to relax in any measurable way. The two failures neither (a) demonstrated the ability to relax, nor (b) reported subjective feelings which would be associated with learning to relax or to control their muscle tensions.
For an 'in depth' look at the entire area of phantom pain, one might read the book Phantom Pain by Sherman, , Devor, Jones, Katz, Marbach, 1996.