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Controlled trial of EMG feedback in muscle contraction headache.

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Controlled Trial of EMG Feedback
in Muscle Contraction Headache
Peter B r u h n , P h D , Jes Olesen, M D , and B j ~ r nMelgaard, MD
Twenty-eight patients suffering from severe, longstanding muscle contraction headache were randomly assigned to
two groups, one receiving electromyographic (EMG) feedback therapy a n d t h e other, “most suitable alternative
therapy.” Headache intensity a n d severity as well as d r u g intake were reduced in the feedback group ( p 0.01) as
opposed to no improvement i n t h e control group. T h e positive treatment effect in the feedback g r o u p persisted
through a three-month follow-up period. EMG feedback therapy i s effective in the treatment of muscle contraction
headache even in its chronic, severe form, which is resistant to traditional treatment methods.
Bruhn P, Olesen 1, Melgaard B: Controlled trial of EMG feedback in muscde contraction headache.
Ann Neurol 6:34-36, 1979
lwenry-eight consecutive patients with MCH [ 11 participared voluntarily in the study. They all suffered from persistent headache of a sready o r fluctuating intensity. The
pain was described as pressing and aching, often radiating
to the templer, jaws, or vertex. O n palpation, the chewing
and neck muscles were render. I n addition to the daily
headache, 4 patients had rare “migrainelike” exacerbations.
The mean heatiache duration was 11.5 years, the mean
headache intensity was 1.6 on a 0 to 3 patient self-rating
scale, and an average of two-thirds of the subjects’ time was
occupied by headache. Mean consumption of analgesics was
2.6 units ( 1 unit equivalent to 500 mg of acetylsalicylic acid)
per day. Eighteen patients had received one or more series
ofphysical therapy treatments, all had previously had medical
therapy, and most had tried one or more paramedical
treatments. None were on disability pension, but all were
frequenrly absent from work, often for long periods, because of headaches.
Following a four-week baseline period, the subjects were
randomly allocated to the biofeedback group ( A ) or the
control group (B).T h e biofeedback group received sixteen
training sessions in the laboratory (twice weekly) lasting 20
minutes each. Commercial EMG feedback equipment was
used (Biotens, Biometer, Odense, Denmark). Surface
electrodes were attached in a standard position over the
frontalis muscles, and the mean integrated EMG was recorded. The feedback signal was a continuous tone generated by a voltage-corrected oscillator. The pitch varied with
the EMG, a low tone indicating a low tension level. The
sensitivity of the feedback loop was adjusted to make the
task progressively more difficult as rhe patient improved.
In 5 cases the electrode placement was changed t o temporal or masseter locations as relaxation of the fronralis
muscles was achieved. Following introductory instruction
covering the goal and rationale of the therapy, the patients
were urged to d o “whatever would reduce the pitch of the
feedback signal.” N o supplementary instructions about relaxation were given in the laboratory. but patients were
asked to use the acquired skills during 30 minutes of home
practice a day. Initial EMG values were recorded at the
beginning of each training session to check if the patient
was able to reduce tension without feedback.
Group B received the “most suitable alternative therapy.” Its nature was determined in each case by clinical
From rhc- D c p r t r n e n r of Ncuromcdicinc., Kigshospiralet, C o p t n h a g t n , Dcnmark.
Address reprint requests t o D r Bruhn, Department of Ncuromedicinr. Rigshospiraler, DK-2 I00 Copenhagen, Denmark.
Muscle contraction headache (MCH), also k n o w n as
tension headache, is familiar t o m o s t people. A s a
chronic or frequently recurring condition, it assumes
major medical and socioeconomic importance [ 7 ] .
A b n o r m a l tension in t h e cranial muscles (frontal,
temporal, masseter, and occipital) is considered t h e
cause. Conventional t r e a t m e n t is based largely o n unsatisfactory and nonvalidated m e t h o d s 15, 71.
Electroniyographic t EMG) feedback training, recently introduced as a new t r e a t m e n t [ I ] ,is a i m e d at
teaching t h e headache patient voluntary relaxation of
t h e spasmodic muscles. T h i s is achieved by providing
t h e subject with immediate (feedback) information
a b o u t his o r h e r o w n tension level, which has p r o v e d
highly effective i n teaching patients muscle c o n t r o l
[ 2 ] . Very f e w controlled clinical trials evaluating
EMG feedback against placebo have b e e n p e r f o r m e d
to validate t h e method 13, 4 , 6, 81, and those that
have b e e n d o n e involve small samples. Nevertheless,
EMG feedback therapy for MCH is n o w widely used.
We report t h e result of a clinical study c o m p a r i n g
t h e EMG feedback m e t h o d against o t h e r therapies in
a g r o u p o f patients with chronic, incapacitating MCH
resistant t o trliditional treatment.
Patients and Methods
Acceprcii f o r puhlrLation Dec 10. I978
34 0364-51 3‘t~-c)/O’0034-0~$01 2 5 @ 19-8 by Peter Bruhn
and 1 patient who stopped after three feedback sessions
were excluded.) The 23 patients were reexamined one,
three, and six months after the initial examination. Each
kept a diary in which maximal headache intensity (0 to 3
scale), headache duration (morning, afternoon, evening),
and drug intake units were recorded daily throughout the
study. These data served as dependent variables.
when pretreatment values were compared to values
during the last two weeks of therapy ( p s 0.01, Wilcoxon test) (Table l ) ; no significant change was seen
in Group B. When patients were ranked by the referring neurologists, who were not aware of their treatment status, Group A fared better than Group B ( p
< 0.01, Fischer’s exact test) in terms of overall outcome.
A reduction to 0 to 25% of baseline level was
considered an excellent response, 26 to 50% good,
51 to 75% moderate, and 76% or more unsatisfactory. Seven of the 13 patients in Group A showed
excellent to good improvement in the headache
index as opposed to only 1 out of 10 controls. Drug
intake was reduced to 50% or less in 10 of the 13
patients treated with biofeedback and in 2 of the 10
controls (Table 2 ) . A gradual reduction of the frontalis EMG level was seen in all Group A patients, the
mean initial level of 9.9 p v being reduced to 5.9 pv,
about 60% of the initial value, at the sixteenth session. Repeated palpation of the chewing and neck
muscles in 9 Group A patients revealed a posttreatment decrease in tenderness ( p s 0.05, Wilcoxon
test) that correlated ( p d 0.05) with the declining
headache index. Ten of the 13 treated patients continued their headache diary for a three-month
follow-up period. Both headache index and drug intake were unchanged when data from the final two
weeks of follow-up were compared to those from the
last two weeks of the treatment period (Wilcoxon
test).
Correlations were calculated between treatment
effect (reduction in headache index) and the variables
of age, initial frontalis EMG level, muscle tenderness,
pretreatment headache index, and drug intake. Only
/
20
-
DURATION
k \/”2.L/
15?
lo
3
0
Q
9
5-,
L,-R4SE
I
4
TREATMENT
FOLLOW UP
12 13
2 L WEEK
5
Mean headache intensity, headache duration, and drug intake, recorded daily by patients i n a headache diary, are depicted during the baseline period and during treatment with
either electromyographicjiedback(Group A ) or “bestavailable
other therapy” (Group Bi. A decrease in intensity, duration,
and drug intake, i s clearly seen i n the biofeedback group,
whereas the control group did not improve signzficantly. During a three-month follow-up period the improvement was fully
maintained.
a low initial tension level favored a positive treatment
response (Y = 0 .5 ,p s 0.05, Spearman rank order
correlation).
Discussion
The present study demonstrates that EMG feedback therapy for MCH in its chronic and severe
forms is highly effective. A favorable outcome lasted
for at least three months without “reminder” sessions. Significant reductions in muscle tension, tenderness, complaints of pain, and drug consumption
were obtained in more than half of the patients. This
finding substantiates that of previous series with
smaller sample sizes, insufficient clinical data, or lack
of follow-up. Furthermore, unlike previous series
which have compared EMG biofeedback with
placebo, the present study demonstrates biofeedback
therapy to be significantly better than the most suitable alternative therapy.
It is surprising that the control group did not
benefit from the therapeutic methods. In our opinion
this was due to the extreme severity and chronicity of
Bruhn et al: E M G Feedback in Tension Headache
35
Table I hleuri Week0 Headache Indexd aiid Drug Irrtakeh
t n the EhIG Feedback Group arid Control Group Before, Durtrig, a d After Therap)
EMG Feedback (N
Time of
Determination
Headache
Index
Baseline period
Treatment period
Follow-up ~ e r i o d
1'9 jp c 0.01"
101
106
=
Control (N
13)
Drug
Intake
(analg.
units)
22 } p
9
9
INS
=
Drug
Intake
(analg.
Headache
Index
169
0.01
168
1 NS
10)
units)
INS
l6
12
...
~ N S
...
aHeadache intensity times headache duration.
"Calculared in analgesic units equivalcnt to 300 mg of acetylsalicylic acid.
'Wilcoxon rest.
NS
=
not signihcant.
Table 2 Rcs/iltJ of Treatment
I?)
Ferdhaik and Control Groups"
Outcome
Determination
Excellent
( s25%')
Good
(26-50V)
Moderate
(51-75';)
(2
i
2
2
1
0
5
3
0
1
0
9
1
7
Unsatisfactory
76")
Feedback
group ( N
13)
Headache index
Drug Intake
Control
group ( N - 10)
Headache i i i d ex
D r w intake
~
8
1
1
"Outcome calculated in percentage of baseline values
headache in these patients, who had previously tried
many kinds of treatment without success.
The feedback technique employed by us and
others is based on the assumption that frontalis relaxation training generalizes to other head and neck
muscles. This did nor happen with 2 of our patients,
in whom masseter hypertrophy and tenderness did
not respond t o frontalis feedback; but 7 patients responded well to frontalis feedback even if their major
tension and tenderness were localized to other head
muscles. The problem of generalizing the frontalis
relaxation training needs further investigation, but at
present it seems reasonable to supplement the frontalis feedback with feedback training of other tender
muscles.
H o w to ensure that relaxation skills acquired in the
laboratory will help patients relax in other life situations is another problem. The favorable treatment
results indicate that this often happens, but it is notable that 3 patients learned to relax in the laboratory
without resultant decrease in muscle tenderness or
headache. Training methods facilitating transfer of
relaxation to nonlaboratory conditions are presently
being tested in our department.
EMG feedback has a potential psychological value.
Drug therapy and physical therapy reinforce a ten36 Annals of Neurology
Vol 6
No 1 July 1979
dency to dependent behavior in many headache patients, but biofeedback educates the patient to control his own well-being.
References
1. Ad H o c Committee o n the Classihcation of Headache:
Classification of headache. JAMA 1 7 9 : i 17-7 18, 1962
2, Budzynski TH, Sroyva JM, Adler CS: Feedback-induced rnuscle relaxation: application to tension headache. J Behav Ther
Exp Psychiatr 1:205-211, 1970
3 Budzynski TH, Stoyva JM, Adler CS. e t al: EMG biofcedback and tension headache: a controllcd ourcome study.
Psychosom Med 35:484-496, 1973
4. Cox DJ, Freundlich A, Meyer RG: Differential effectiveness
of electromyograph feedback, verbal relaxation instructions,
and medication placebo with tension headaches. J Consult
Clin Psychol 43:892-898, 1975
5 . Dalessio DJ: Wolffs Headache and Other Head Pain. New
York, Oxford University Press, 1972
6. Kondo C, Canter A: True and false electromyographic feedback: effect on tension headache. J Abnorm Psychol 86:
93-95, 1977
7. Lance JW: Mechanism and Management of Headache. Third
edition. London, Butrenvorth, 1978
8. Philips C: The modification of tension headache pain using
EMG biofeedback. Behav Res Ther 15:119-129, 1977
9. Waters WE: The Epidemiology of Migraine. Six Surveys of
Headache and Migraine. Berkshire, England. Boehringer Ingelheim Bracknell, 1974
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