CASE HISTORIES AND SHORTER COMMUNICATIONS

Relief of phantom limb pain after EMG biofeedback-assisted relaxation: a case report

(Received 4 December 1979)

Summary-Both EEG and EMG biofeedback were used to treat severe, chronic phantom lib pain in a 54 yr-old man. Although EEG biofeedback was in&ective, EMG biof~d~ck-baste relaxation of the muscles in the stump allowed the patient to greatly reduce the frequency and intensity of the pain after about 4 h of practice. Both somatic and cognitive variables may have contributed to the effectiveness of the procedure.

Phantom limb pain occurs in about 35% of persons after amputation (Melzack, 1971). Although in most instances the pain disappears within -months, the pain is often disabling and may persist for years in 5-10’~ of the cases. Treatment by neurosurgery, such as transection of the dorsal roots to interrupt agerent input from the periphery, has generally been ineffective (Melzack, 1971; Pagni and Maspes, 1972). The poor results obtained by deafferentiation~ along with the occurrence of phantoms in paraplegics and in cases of congenital absence of limbs, have been interpreted as strongly supporting a ‘central’ theory in which the activity of cortical and subcortical systems is responsible for the pain (Weinstein, 1969). This theory is consistent with the action of narcotic analgesics on the CNS. but long term treatment with this drug class is undesirable because of the tolerance and physical dependence which often develops. That peripheral inguences may also alter phantom pain has been demonstrated by the temporary effectiveness of saline injections into the stump or interspinous tissue (Livingston, 1943, as cited by Meizack, 1971; Pagni and Maspes, 1972); but one disadvantage of this therapy is that it requires frequent outpatient treatment.

Recently, more attention has been directed towards non-invasive procedures for pain control that do not require continuing outpatient services and can be self-administered by the client after a period of initial training. Transcutaneous stimuiat~on, alpha EEG and EMG biofeedback training, and hypnotic training ate examples of non-invasive procedures that have been utilized with some success in pain control programs (Melzack, 1975; Melzack and Perry, 1975; Sternbach, 1978; Hilgard, 1978). This case report describes the use of EEG biofeedback training and EMG biofeedback-assisted relaxation training in an attempt to control phan- tom limb pain in a single client.

At the time of the treatment. Mr. A. L. was a 54 yr-old disabled veteran with an above-the-knee amputation of the left leg that was necessitated by severe arteriosclerotic pain and the development of gangrene. He served in the Army during WWIX where he had sustained deep shrapnel wounds and phosphorus burns. After the war he worked steadily as a pipefitter. In f962 he sustained a rupture of a left middle cerebral artery anurysm, which was clipped via craniotomy. Shortly after this surgery he was in an automobile accident and began having seizures, which were controlled by phenyltoin. He continued working until 1969 when he was disabled with emphysema. From that time he has worked a small garden during the summer. His circulatory problems began in 1975 when he noticed a cramping in his legs after sustained walking. Nocturnal cramping began approximately 1 yr later. In 1977 he underwent right leg vein stripping which improved his circulation and mobility. However, in January 1978 he bagan having severe ‘burning’ pains in his left foot and toes and was admitted to the VA Medical Center.

During his hospital stay he received several bypass grafts in an attempt to increase the blood supply to his left leg. However. dry gangrene appeared in his toes in April 1978, resulting in a left trans-metatarsal amputa- tion followed by continued foot pain, and 2 weeks hter by a left above-the-knee amputation.

Characreristics of pain and phantom limb The foot pain, but not the toe pain, that was present before amputation continued as phantom pain after the

limb was removed. The client localized the pain deep in the heel and on the outside edge of the foot. Using the McGill Pain Questionnaire (Melzack, !975), he described the pain as burning, heavy, tingling, drawing exhausting, gruelling~ intense, and torturing. The pain was not similar to any other pain he had previously experienced. The pain was continuous for 3 months after surgery and then became episodic, occurring in bursts of about 3-30 s duration about once per minute for periods of hours several times per day. The pain was worse at night and interfered with sleep. The phantom pain was more intense during urination. The phantom leg had not become foreshortened and was perceived to be bent at a right angle at the knee while he was sitting or lying on his stomach, but was felt to be straight when lying on his back.

Other factors

At the time the client was referred to me for possible treatment (August, 1978) he was receiving dextropopoxy- phene. Although this drug incompletely controlled the pain, he refused further treatment with more potent narcotic analgesics (morphine, me~ridine) because he had become physically dependent upon those drugs

355

356 CASE HISTORIES AND SHORTER COMMUNTCATIONS

shortly after the amputation. In spite of his pain and the presence of multiple chronic diseases, he was optimistic, was highly motivated in physical therapy, was being fitted with a prosthesis, and preferred to do as much for himself as possible. After a general explanation of biofeedback procedures, he readily consented to try it for relief of pain.

METHODS &ND RESL’LTS

After taking a history, the client was told that his pain was most likely the result of brain acttvity and that there was a ‘slim chance’ that learning to produce certain brain wave (EEG) frequencies and amplitudes might alter the perception of the pain. He was then given a complete explanation of EEG biofeedback training. He was also told that this was an exploratory treatment, and was informed that the pain might also be made temporarily worse by such training. The client agreed to try the procedure.

Two EEG biofeedback sessions, each about 45 min long, were conducted using an Autogenic Model 12Oa set on the audio feedback mode. Electrode pfacements- in the temporaI-o~~pitai. temporal-parietal. and also over the sensori-motor cortical area on the right side of the head were used. The client was able to keep EEG frequencies within the 4-8 Hz (theta), 8-13 Hz (alpha) and 13 + Hz (beta) ranges with amplitudes of 30-70 mV for sustained periods of time, often exceeding 10 min. Pain episodes, occurring about I/min. were unaffected by the maintenance of any EEG frequency. By mutual agreement. the treatment was discontinued after the second session.

During further discussions with the client, he indicated that the tip of his stump would ‘draw down’ with the onset of the pain. Observation showed that the apex of his stump was pulled dorsally by strong contraction of the muscles of the underside of the thigh with each pain episode. The client was unaware of these muscle contractions. It was therefore suggested to him that EMG biofeedback-assisted relaxation of the stump muscles be tried to see if that procedure might make him more comfortable and perhaps decrease his reactivity to the pain. Given the failure of the EEG biofeedback and the exploratory nature of the proposed EMG treatment. expectations for success i.n actually controlling the pain were quite low.

The concepts underlying EMG biofeedback were explained, his written consent was secured, and the re- lationship between audio feedback and muscle tension was demonstrated by placing the three Ag/AgCl elec- trodes on the ventrat surface of his left arm and having the chent flex his left hand. (The instrument was an Autogenics Model 1700 set in the analog tone feedback mode (AN,), with a I s response time, and with the bandpass selector set at IO&200 Hz). After the demonstration, the electrodes were relocated on the dorsal surface of the stump. The reference electrode was placed on the dorsal midline of the thigh. 4 cm proximal to the apex of the stump (over S. Tendinosus). The two active electrodes were placed lateral to the midline about 10 cm from the apex (over 8. Femoris and S. Membranosis, respectively). These muscle locations are only approximate since the anatomy of the leg may have been altered by the surgery.

Initial measurements, made without feedback, indicated that the resting EMG was about 0.2 mV and that muscle contractions equal to or greater than 0.75 mV for 5 s or more were always associated with intense phantom pain. Therefore, those parameters were used to define a pain-related ‘contracture’. During a 10 min baseline measurement period, 13 contractures occurred. Audio feedback was then turned on, and for 20 min the client practiced aiternately contracting and relaxing the stump muscles. The effect on EMG levels of shifting his attention towards and away from the stump was also explored at this time. If the client focused his attention on the stump or manipulated the stump with his hands, relaxation was hindered. However. voluntary contraction of the stump muscles did not elicit pain. On the contrary, voluntary contraction of the stump during a spontaneous contracture could abort the pain episode. After the active training period, the client spent 10 min, unassisted, trying to keep the stump relaxed. Six contractures were noted during this post-training period.

In the second 45-min session the next afternoon, the client received further instruction and practice in relaxation using the EMG unit. Although he experienced no pain episodes or contractures during the 10 min post-training measurement period, the significance of this lack of pain is difficult to interpret because he had had only one pain episode during the 10min baseline period. On the third afternoon, however, he was experiencing considerable pain and had 15 contractures in the first 10 min of the session. After 30 min of relaxation practice, he was able to entirely eliminate pain episodes during the 10 min post-training period.

Although he was able to eiiminate phantom pain episodes during EMG biofeedback sessions, he was not successful in controlling the pain at other times during the day. He continued to claim that he could not proprioceptively ‘feel’ the muscle contractute. In order to increase the amount of relaxation practice, the patient was instructed in the use of a smaller, more portable, EMG biofeedback unit (Bio-Feedback Systems Model PE-2). In a I-h training session he was able to’maintain a level of O-10 PA in the stump muscles (at the “High” sensitivity setting) and eliminate pain episodes.

The portable EMG biofeedback unit was then placed at bedside, allowing daytime and evening relaxation practice. Daily sessions using the Autogenic unit were discontinued. He used the portable machine for 1 h that same evening and twice a day for 1 h from the fourth to ninth treatment day. Biofeedback was discontinued on the ninth day (August 31, 1978) because the patient said he could now ‘feei’ his stump musgtes tighten and could voluntarily relax them without assistance from the machine. He reported pain-free periods of 2-4 h during the daytime, and, if awakened from sleep by pain, he could abort the pain by relaxing the stump and then return to sleep. He could also abort pain episodes during the day and reported that the pain was generally less intense. He was pleased with the results and decreased his use of dextropopoxyphene for pain and Rurazepam for sleep. The control over pain continued for the remainder of his stay in the hospital, a period of 3 weeks. Two weeks after discharge (5 weeks after treatment ended) a telephone follow-up was made. About 5 days after discharge his prosthesis caused stump irritation and a return of phantom pain episodes. He reported that he could no longer relax by himself. but that taking diazepam helped ease the pain: which suggests that he had lost the ability to voluntarily relax the stump. Because he lived in a mountainous area 75 miles from the Medical Center, he was not able to return for outpatient relaxation sessions.

DISCUSSION

The results of this single case study suggest that EMG biofeedback-assisted relaxation enabled an individual

CASE HISTORIES AND SHORTER COMMUNICATIONS 3.57

to control and temporarily eliminate frequent and intense phantom limb pain. That control over the pain was attained after 4 h of biofeedback training over a 5-day period further suggests that this procedure has the potential for being a cost-effective treatment method for phantom limb pain. The return of the pain after discharge points out the necessity for periodic supervised relaxation practice throughout the early phases of the rehabilitation process.

EMG biofeedback-assisted relaxation may have altered phantom pain by a variety of mechanisms. Relax- ation of the stump muscles could have decreased pain by altering the degree or type of peripheral input. This possibility is supported by the finding that voluntary contraction of the stump muscles could shorten a pain episode. However, relaxation of the stump muscles was accompanied by a genera1 relaxation of the body. and such relaxation is usually accompanied by a decrease in sympathetic tone. Because the sympathetics are believed to be involved in peripheral pain (Wall, 1974), it is possible that a decreased tone secondary to relaxation may have had a positive effect.

Distraction may also be involved. Morgenstern (1964) found that when phantom pain patients concentrated on performing several sensorimotor tasks in the presence of sensory distractions (e.g.. flashing lights), in daily sessions for a period of 3 months, phantom limb was substantially reduced or abolished. Perhaps the EMG relaxation process provided a similar kind of distraction, since successful relaxation often requires a shift in thinking away from pain and current problems to pleasant or neutral topics.

Melzack and associates (1971, 1975, 1978a and b) have conducted a~ number of investigations into the phenomenon of phantom pain and have proposed that both peripheral and central processes are intimately involved. They have proposed that pain is related to neuronal patterns generated in the major sensory projec- tion systems. These pattern generating mechanisms may be influenced by a variety of variables-peripheral and central, defined cognitively as well as somatically. Such a formulation is supported by the results cited above and by findings that auditory input, expectation, suggestion, hypnosis, and long-term EEG biofeedback can also favorably influence phantom and other pain (Craig et al., 1978; Hilgard, 1978; Meichenbaum, 1977; Melzack and Perry, 1975).

Although a clinical case study without reversal of treatment conditions cannot assess the contribution of non-specific variables, it is unlikely that favorable expectations contributed to the effectiveness of the relaxation procedure, or that the decline in pain was simply a function of time since amputation. Beneficial effects of EMG biofeedback on the pain were not anticipated by myself or the client, especially after the failure of the EEG biofeedback procedure. and the return of the phantom after his discharge was an unplanned reversal -<hat eliminated the passage of time as an important factor. Controlled studies will be necessary to evaluate the effectiveness and specificity of the use of EMG biofeedback-assisted for phantom limb pain.

Acknowledgements--I greatly appreciate the assistance of James Norton, Ph.D., Dennis Kinlaw, M.D., and the staff of the 2-South Nursing Self-Care Unit, Veterans Administration Medical Center, Lexington, Kentucky, U.S.A.

Psychology Service Veterans Administration Medical Center Lexington Kentucky 4051 I and

JOHN D~UGHERTV

Departments of Psychiatry and Pharmacology Uniuersity of Kenrucky Medical Center

REFERENCES

CRAIG K. D., BEST H. and BEST A. J. (1978) Self-regulatory effects of monitoring sensory and affective dimen- sions of pain. J. consult. clin. Psycho/. 46, 573-574.

HILGARD E. R. (1978) Hypnosis and Pain. In R. A. STERNBACH (ed.), The Psychology of Pain. Raven Press, New York.

LIVINGSTON W. K. (1943) Pain Mechanisms. Macmillan, New vork. MEICHENBAUM D. (1977) Cognitive-Behavior Modification. Plenum, New York. MELZACK R. (1971) Phantom limb pain: Implications for treatment of pathologic pain. Anesthesiology 35,

409-419. MELZACK R. (1975) Prolonged relief of pain by brief, intense transcutaneous somatic stimulation. Pain 1,

357-373. MELZACK R. and DENNIS S. G. (1978a) Neurophysiological foundations of pain. In R. A. STERNBACH (ed.), The

Psychology of Pain. Raven Press, New York. MELZACK R. and LOESER J. D. (1978b) Phantom body pain in paraplegics: Evidence for a central “pattern

generating mechanism” for pain. Pain 4, 195-210. MELZACK R. and PERRY C. (1975) Self-regulation of pain: The use of alpha-feedback and hypnotic training for

the control of chronic pain. Expl Neural. 46, 452-469.. MORGENSTERN F. S. (1964) The effects of sensory input and concentration on post-amputation phantom limb

pain. J. Neural. Neurosurg. Psychiat. 27, 58-65. PAGNI C. A. and MASPES P. E. (1972) A new approach to the surgical treatment of phantom limb pain. In J. P.

PAYNE and R. A. P. BUNT (eds.), Pain. Williams and Wilkins, Baltimore. STERNBACH R. A. (1978) Clinical aspects of pain. In R. A. STERNBACH (ed.), The Psychology of Pain. Ra\en

Press, New York. WALL P. D. (1974) Physiological mechanisms involved in the production and relief of pain. In J. J. BONICA, P.

PROCACCI and C. A. PAGNI (eds.), Recent Advances on Pain. Charles C. Thomas, Springfield, IL. WEINSTEIN S. (1969) Neuropsychological studies of the phantom. In A. L. BENTON (ed.), Conrrihurions to Clinical

Neuropsychology. Aldine Publishing, Chicago.