The Use of EIectromyographic
and Temperature Biofeedback for Treatment of Cramping and Burning Phantom
Richard A Sherman,
LTC, Medical Service, US Army Chief,
Clinical Biometrics Service
Dept. of Clinical Investigation
Fitzsimons Army Medical Center Aurora , CO.
Virtually everybody who has had an amputation
reports feeling sensations which appear to emanate from the amputated
portion of the limb. Most of the time, these "phantom" sensations
are painless and of sufficiently low intensity to be no more than a mild
distraction(9). The sensations are usually similar to those which would
be felt in an intact limb, including warmth, itching, sense of position,
and mild squeezing. Awareness of details of the limb's shape and perceived
ability to move it tend to fade with time. However, almost all amputees
report continuing to feel at least some phantom sensations throughout
the remainder of their lives. When phantom sensations become intense enough
for the amputee to define them as painful, they are called "phantom
pains". The neural mechanisms which permit perception of phantom
limbs are well recognized(3,4). Sensations reaching the brain are identified
for location on the skin by the homunculus, in the sensory cortex, which
contains a representation of the entire body surface. Thus, a pinch of
the left index finger tip stimulates a location on the homunculus representing
the left index finger tip.
If the finger was amputated and a signal
was started by pressure, etc., anywhere along the remaining nerve paths
between the finger stump and homunculus, the resulting sensation would
seem to emanate from the finger tip because the paths do not change much
after amputation and the brain has no way to know that the finger tip
is not present.
Figure 1. Common descriptions of phantom pain
Phantom limb pain occurs among between 50
and 80 percent of amputees(9,10). The most common descriptions of phantom
pain are variants of cramping, burning/tingling, and shocking/shooting/stabbing
(Fig. 1). Each amputee tends to report the same one or two descriptions
of phantom pain whose locations within the phantom remain consistent over
time. A large minority have episodes severe enough to interfere with work,
sleep and desired social activities which occur frequently enough to require
Phantom pain can occur anytime, from just
after an amputation to years later. Its occurrence is not related to psychological
factors(12), age, sex, location of the amputation, or reason for the amputation
(e.g. trauma vs. disease). Different individuals report their phantom
pains to be affected by different environmental variables such as changes
in humidity and temperature(2,10). As is true with all chronic pain syndromes,
stress and fatigue can magnify the sensations but there is absolutely
no evidence that any psychological factors cause phantom pain(1,12). Pain
from pinched nerves in the back and other sources is referred to the phantom
limb as it would be to the original limb.
Recent surface electromyographic studies(8,11)
have demonstrated that the major muscles in the residual limb tense up
several seconds before the cramping phantom limb pain begins and that
these muscles remain tense for much of the duration of the episode. The
pattern of tensing is usually shown by an abrupt increase in magnitude
of surface electromyogram to about twenty times baseline values. Other
studies(6) have demonstrated that burning phantom limb pain is closely
associated with reduced blood flow in the residual limb. There is currently
no evidence associating shooting/shocking descriptions of phantom pain
with specific physiological mechanisms. However, very similar sensations
are provoked during ectopic stimulation of nerves from a neuroma.
In the past, the success rate for treatment
of phantom pain has been dismal, with only about one percent of treated
amputees reporting effective relief lasting for at least a year(9,10).
At least forty-three ineffective treatments were in common use until recently(10).
They range in invasiveness from lobotomies and major spinal surgery, through
surgical revision of the residual limb, psychotherapy, and psychoactive
drugs, to transcutaneous electrical stimulation and similar techniques.
The only treatments consistently able to ameliorate phantom pain were
sympathetic locks and sympathectomies which were useful for burning phantom
pain for up to a year.
Current treatments are based on the mechanisms
discussed above and have been proven to be more effective(5,7). Cramping
phantom pain responds well to treatments which result in preventing the
residual limb from tensing up abnormally, while burning phantom pain responds
well to treatments which increase blood flow, both in and out of the residual
limb. No treatments have been identified as being consistently effective
for shocking/shooting descriptions of phantom pain. The diagnostic decision
making process for choosing the treatments most likely to be effective
for different descriptions of phantom pain has been detailed elsewhere(3).
For patients who describe burning/tingling
phantom limb pain and have an essentially normal reactive vascular system,
a trial of temperature biofeedback may provide relief. We start these
patients out with surface electromyographic biofeedback because we find
that it is easier to learn and gives trainees the confidence they need
when learning to control their limb temperature. If the patient describes
cramping/squeezing phantom limb pain, and is able to learn control of
the voluntary muscles, a trial of surface electromyographic biofeedback
is appropriate. Amputees who give mixed descriptions of phantom pain which
include shocking/shooting sensations may have success learning to control
other descriptions of phantom pain but the shocking/shooting sensations
are likely to remain unchanged. Amputees reporting combined burning and
cramping pain are given treatments aimed at controlling both underlying
The specific aim of the treatment is to teach
amputees with burning/tingling phantom pain to habitually and unconsciously
keep their residual limbs as warm as the intact limb. For amputees with
cramping pain, the aim is to teach them to prevent the onset of the types
of increases in muscle tension in the residual limb which lead to pain.
These aims are approached through several overlapping stages:
- First, subjects are shown the relationship
between the residual limb's temperature or muscular activity and the
onset and intensity of phantom pain, so they are absolutely convinced
of the relationship.
- Next, they are given muscle tension and
temperature awareness training very similar to Jacobson's system. They
are given tape recorded exercises to play at home at least twice per
day. The aim of this phase is to begin increasing their awareness of
changes in limb temperature and tension patterns as well as to begin
helping them learn to control these parameters.
- After several weeks, the tapes are used
only once per day and the patients begin doing the exercise on their
own at least once at home and once while out in their normal work environment.
This is intended to begin generalizing their awareness of changes in
the parameters to their normal environment.
- The week after, subjects begin home training,
they participate in weekly or biweekly biofeedback sessions conducted
in the clinic. The sessions follow the guidelines detailed in the Association
for Applied Psychophysiology and Biofeedback's application standards
Figure 2. Placement of EMG and temperature sensors
After control is demonstrated in the finger,
the sensor is mounted on the warmest portion of the residual limb (figure
2B) and ability to control temperature of that area is trained. This is
a slow process which can take eight sessions or more. The sensor should
not be placed near the end of the residual limb as the vascular bed, in
that area, is highly abnormal and most subjects have not learned to control
limb temperature when the sensor is placed there.
Subjects who are being taught to recognize
and control muscle tension receive a similar program. Their foreheads
are insturmented with surface electrodes (figure 2C) and signals are fed
back through a light bar or auditory display (figure 5.) Picture of
MyoTrac 2 Dual channel EMG system provided by Thought Technology Ltd.)
- Subjects being taught temperature
biofeedback begin by having the dominant index finger instrumented
with a single temperature sensor (fig. 2A). If neither hand
is present, the toes are used. Skin temperature is fed back
to the patient from both a line graph or bar graph display
(fig 3, 4) and an auditory signal (illustrations are from
Thought Technology's ProComp+/DOS biofeedback system).
- They continue to receive training
for this area until they demonstrate the ability to consistently
and reliably raise their finger temperature. We do not normally
either have patients work to a preset goal or require the
ability to quickly raise, lower, and then raise finger temperature,
because achievement of these goals does not seem to relate
to symptom control. Instead, we tailor each treatment to
the individual's ability to raise temperature.
Figure 4. Line graph
Instruct the patient to lower the tone and
light bar readings. When they can demonstrate the ability to reliably
relax the facial muscles, the sensors are moved to the right or left trapezius
sites where similar training is performed (figure 2D).
After control is demonstrated, place the
EMG electrode over one of the major muscles of the residual limb (figure
2E) and teach the subject to recognize tension patterns by controlling
muscle tension in the limb. This process can take twelve sessions or more.
Awareness of the residual limb's temperature
and/or patterns of muscle tension in the patient's environment is emphasized
throughout the training process so that control is eventually achieved
while the subject is in the normal environment without the subject having
to concentrate on continuously maintaining control.
Figure 5. Light bar feedback display
Biofeedback can be an effective treatment
for cramping and burning phantom limb pain when used with appropriate
patients in conjunction with home based temperature and muscle tension
recognition and control training. This modality should be attempted
before using medication or other invasive therapies as it is at least
equally effective and relieves patients of the need for continuing use
of drugs which usually have deleterious side effects.
- Arena. J., R. Sherman, G. Bruno and
J. Smith: The relationships between situational stress and phantom
limb pain: Cross-lagged correlational data from six month pain logs.
Psychosomatic Research, 34: 71-77 (1990).
- Arena, J., R. Sherman and G. Bruno:
The relationship between humidity level, temperature and phantom limb
pain: Preliminary Analysis. Biofeedback and Self-Regulation, 14: 128
- Sherman, R.: Phantom limb and stump
pain. In Neurologic Clinics of North America. (Portenoy. R. Ed.) Philadelphia,
W.B. Saunders Co. (1989).
- Sherman, R., J. Arena and J. Ernst:
The mystery of phantom pain: Growing evidence for physiological mechanisms.
Biofeedback and Self-Regulation, 14(4): 267-280 (1990).
- Sherman, R., Arena, J., Griffin, V.,
Bruno, G., Cocilovo A.: Biofeedback for the treatment of phantom limb
pain: An update. Biofeedback. 7(3): 7-8 (1991).
- Sherman, R. and G. Bruno: Concurrent
variation of burning phantom limb and stump pain with near surface
blood flow in the stump. Orthopedics, 10: 1395-1402 (1987).
- Sherman, R., N. Gall and J. Gormly:
Treatment of phantom limb pain with muscular relaxation training to
disrupt the pain/tension cycle. Pain 6: 47-55 (1979).
- Sherman, R., V. Griffin, C. Evans and
A. Grana: Temporal relationships between changes in phantom limb pain
intensity and changes in surface electromyogram of the residual limb.
International Journal of Psychophysiology, In Press, 1992.
- Sherman, R. and C. Sherman: Prevalence
and characteristics of chronic phantom limb pain among American veterans.
Am. J. Phys. Med. 62: 227-238 (1983).
- Sherman, R. and C. Sherman: A comparison
of phantom sensations among amputees whose amputations were of civilian
and military origins. Pain 21: 91-97 (l985).
- Sherman, R. and C. Sherman: Physiological
parameters that change when pain changes: Approaches to unraveling
the "cause-or-reaction" quandary. Bulletin of the American
Pain Society. 1(4): 11-15 (1991).
- Sherman, R., C. Sherman and G. Bruno:
Psychological factors influencing chronic phantom limb pain: An analysis
of the literature. Pain 28: 285-295 (1987).
- Sherman, R., C. Sherman and L. Parker:
Chronic phantom and stump pain among American veterans: Results of
a survey. Pain 18: 83-95 (1984).
- Biofeedback Applications Manual, AAPB,
Acknowledgments and Disclaimer
Figure 1 was originally finalized by Karen Wyatt, Medical Illustrator
at Fitzsimons Army Medical Center, from a draft provided by the author.
The manuscript was reviewed by Vernice Griffin and Cecile Evans of the
Psychophysiology Laboratory at Fitzsimons Army Medical Center. The work
reported here was entirety supported by the U.S, Army and the Department
of Veterans Affairs. However, the opinions and assertions contained
in this manuscript are the private views of the author and are not to
be construed as official or as reflecting the views of the United States
Departments of Veterans Affairs, Army or Defense.
1997 The Biofeedback Federation of Europe