EMG recordings were measured on the frontalis muscle of nine subjects, two of which were controls. Prism was then placed before the subject\u27s left eye and changes in EMG were recorded. We found substantial changes in only three subjects. The other subjects showed no significant trends with the placement or removal of prisms

Conrad, Wayne R

Swanz, Duane M

English

CommonKnowledge

Pacific University 
CommonKnowledge 
College of Optometry Theses, Dissertations and Capstone Projects 
3-1978 
EMG and its possible use in the treatment of vertical imbalance 
Wayne R. Conrad 
Pacific University 
Duane M. Swanz 
Pacific University 
Recommended Citation 
Conrad, Wayne R. and Swanz, Duane M., "EMG and its possible use in the treatment of vertical imbalance" 
(1978). College of Optometry. 477. 
https://commons.pacificu.edu/opt/477 
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EMG and its possible use in the treatment of vertical imbalance 
Abstract 
EMG recordings were measured on the frontalis muscle of nine subjects, two of which were controls. 
Prism was then placed before the subject's left eye and changes in EMG were recorded. We found 
substantial changes in only three subjects. The other subjects showed no significant trends with the 
placement or removal of prisms. 
Degree Type 
Thesis 
Degree Name 
Master of Science in Vision Science 
Committee Chair 
Robert Yolton 
Subject Categories 
Optometry 
This thesis is available at CommonKnowledge: https://commons.pacificu.edu/opt/477 
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EIViG AND ITS POSSIBLE 
USE IN THE TREATMENT 
OF VERTICAL IMBALANCE 
A SENIOR THESIS 
Presented to 
The Faculty of the College of Optometry 
Pacific University 
In Partial Fulfillment 
of the Requirem�nts for the Degree 
Doctor of Optometry 
by 
Wayne R. Conrad 
Duane IVl, Swanz 
March 1978 
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Acknowledgements 
We are grateful to BSK and the Oregon Optometric 
Association for funding of this project. Also, we would 
like to extend our appreciation to Dr. Hobert Yolton for his 
technological help and guidance. 
Also, for his ability to endure the trials and 
tribulations of two fourth year optometry students. 
-1-
ABSTRACT 
EMG recordings were measured on the frontalis muscle of 
nine subjects, two of which were controls. Prism was then 
placed before the subject's left eye and changes in ElV1G were 
recorded. We found substantial changes in only three subjects. 
The other subjects showed no significant trends with the 
placement or removal of prisms. 
Abstract 
Introduction 
Apparatus 
fiiethodology 
Hesults 
Discussion 
Appendix A 
- 2 -
TABLE OF CONTENTS 
• 
Page 
.1 
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.6 
• 7 
• 8 
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10 
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IN'rRODUCTION 
Two general uses of electromyographic feedback have 
emerged so far--its utility in enhancing the control of 
voluntary muscles where that control has either not been 
developed or wher e it is diminished through dysfunction; the 
second area consists of attempts at achieving low levels of 
muscle tension with patients who experience chronic tension 
headaches and chronic anxiety. Other possible uses include 
the treatment of bronchial asthcia, insomnia (Raskin etal , 1973) 
or any disorder that is associated with muscle tension. 
In the past few years, practitioners have found other 
uses for the EMG (electromyograph). Whereas before its main 
u2age was in the area of therapy, it is now found to be a 
va1uable diagnostic tool. In a stu dy by Dr. Raymond R. Roy, 
he found that many patients complaining of chronic, severe 
headache, cervical tension and other related symptoms followi�g 
head or neck in j uries were not malingerers or psychoneurotics. 
In actuality, they did show a problem which had developed from 
a latent binocular stress, and would respond with the proper 
"'.::herapy. 
VVith clinically normal subjects it can be shown that 
prism placed in front of the subject's eyes will show an 
increase in tension in the frontalis, cervical, and trapezius 
muscles, using the EMG (Roy 1961). It has now been found in 
post-whiplash syndromes, that physiotherapy, traction, and 
-4-
pharmacotherapy designed to relax the.posterior cervical tension, 
are only treating a secondary pain and by use of prolonged 
monocular occlusion, a latent binocular stress has been 
shown to be the primary caus e  and once relieved, then all 
secondary symptoms cease to exist. 
Research has shown that the neck is the primary site of 
total body posture and orientation in space, along with the 
extra-ocular muscles and vestibular apparatus. Any type of 
nee� disorder is capable of secondarily altering the postural 
information. 
Eckardt, McLean, and Goodell have shown with electro-
myographic evidence that neck muscle spasm and severe neck 
pain can be caused by a continued abnormal stress on the 
oculorotary muscles (Eckardt, h':cLean, and Goodell l 9i+J). 
An example of how human beings desire to maintain single 
binocular vision has long been shown in ocular palsies. In 
the case of a paresis of a vertical acting extraocular 
muscle, a compensatory torticollis to alleviate the resultant 
diplopia can occur. In this situation, the neck is being 
forced into an abnormal position to be able to compensate for 
a binocular anomaly. Therefore it can be seen that lesions 
which create binocular stress c g n , i·n �·-�n cause � esu1+�n+ � I,; u.� • ' . - . ... a.. •• v 
stress in the neck, 
Vasilescu and Dieckmann (1975) conducted experiments with 
::::1;,G on cervical and spinal m.uscles in relation to torticollis 
or neural muscular activity. Their interest was mainly in 
-5-
relation to disease caused by muscular tension in certain 
muscle groups. They concluded that in the majority of the 
cases of horizontal and rctary torticoll is, a strong 
spontaneous activity exists in the sternocleidomastoi.d 
muscle on the side opposite the deviation of the head, and in 
the splenius, on the side cf the torticollis, and either of 
these two muscle groups may predominate. 
'I'he use of EiviG as a feedback technique for relaxation 
has shown it to be.more effective in lowering tension in a 
spscific muscle then either simple verbal instructions or the 
reduction in tension achieved by the subject's own unaided 
efforts. Those with higher initial EiliG baselines achieved 
greater reductions in tension than those with lower levels. 
�oursey (1975) showed that there is a possible limitation of 
the SMG feedback because of its failure to generalize rolaxa-
ti.on aco:.'oss other parts of the body, An integrated recording 
of m:A.l tiple r::v.sc:Je groups would probably solve this aspect o_ 
tj'1e generalization problem. Ji'lany researc!':ers have had mixed 
results, generally finding that E�J feedback t�aining did not 
generalize outside the laboratory, and that many subjects 
�eached thGlr deepest levels of relaxation by adapting a more 
passive stanc0, letting themselves drift, and essentially 
abandonir.g the task of lowering the pitch (in this case the 
Other �ses of electromyography in relation to the human 
visual system we1�e done by Scott and Collins ( 19? 3). They 
-6-
found that during tracking movements where the muscle worked 
as agonist there is a progressive increase in firing frequency 
that diminished slightly as the eye attained the new gaze 
pos ition . The frequency of activity was the same for each 
fixation position whether that position was attained by 
saccadic movement or by tracking from the earlier target 
position. 
In this study we investigated the relationship between 
change in muscle ten sion and application of vertical prism, 
using the EMG. 
APPARATUS 
For instrumentation we used a Tektronix single trace 
oscilloscope and a Princeton 1-'.A.f.: #11J low level differe::1tial 
pre-amplifier. Our electrodes were surface, tape on electrodes, 
Also, loose prisms in a trial frame were used during the 
rtoom illumination was set at seven footcandles. Patients 
had a 10 minute adjusting period after thG electrodes were 
attached to help eliminate influences caused by nervous 
�ension from the anxiety of the situation. Patient's eyes 
were in the primary position to cont�ol for variability 
of readings duG to different directions of gaze. The target 
fer- these expe:rirEents was two. black lines which were bisected 
on a white background to control fusion, at a distance of 
six meters, Figure J..  
L 
-7-
lViETH ODO LOGY 
Our subjects for this experiment were taken from the 
student population of Pacific University School of Optometry. 
We took vertical ductions with rotary prism s  and a phoropter. 
Then we placed a vertical prism before the left eye equal · 
to the base down duction of the left eye. The orientation 
of the vertical prism was base down left eye. 
A baseline le..rel of tension was taken from EI'JlG record-
ings of the frontalis muscle. Our electrodes, Figure 2, 
were placed such that there were two grounds, one to each ear 
lobe. The third electrode, the active one, was placed approx-
imat8ly one and a half inches above the left eyebrow. 
The prisms were loose prisms placed before the patient's 
sutjects, thereby 
. . . . nnnim1. zing some of the exper-imenta.l 
oias. Readings were taken every minute for a period of 50 
to relax once hooked up to the apparatus. The neY u' I" ·1 r1 · ·, ;- ," "' t Jr • . .L ..... d. - ... l..i. v v .:..:i
for another 10 minutes to see if there were any trends tha.t 
rnig11t occtr  after tf1e pr isrris v1er'-e r'Jerr1ove·d. \tie ther1 
pl0tted the information on a scattergram. 'I'his showed us any 
trends to the data that we have gathered. 
-8-
RSSULTS 
As can be seen from the graphs (1 & 2), subjects (1), 
(6), and (9) show a substantial change in the EMG potentials 
when prisms were introduced before their left eyes, at the 
ten minute interval. Subjects (1) and (6) showed a decrease 
in the electrical potential, whereas subject (9) showed an 
increase. Only subject (1) showed a change in his electrical 
potential upon the removal of the vertical prism, and this 
showed up as a decrease in muscle tension. Subjects (4) and 
(5) were controls. Their graphs shdw no trends beyond a 
flat-line progression with allowable variability. 
There were no apparent effects due to the p:!'."ism inducement 
er removal on subjects (2), (3), (7), and (8). Graph (J) shows 
zero and the change of' the 
See Appendix A for raw data. 
Disc;LTSSIOr� 
At the beginning of our thesis we explored the de (steady 
state,) values of the frontalis, trapozius, levator � and stc'rno-
cliedomastoid muscles. We did not record any changes in the 
::r�;.)G regardless of the amount of prism used. We were only 
able to influence the EivlG with gross motor movements such as 
tead movements and gross contractions of the frontalis muscle. 
-9-
Some of the problems we encountered using the de values 
were the variations caused by heart beats, blinking ar1d any 
extraneous body movements. 
It was at this time we decided to record the ac potentials 
(spikes) because it better represented the changing neural 
impulses into the muscles. The frontalis was the muscle of 
choice because previous literature had indicated that the 
frontalis would act in a shorter period of time to latent 
binocular stress. Therefore, it would be more clinically 
applicable than tr.e previously mentioned muscles. 
As cru1 be seen from the plots, three of the subjects 
showed a substan.tial change in potentials when pr ism was 
placed before the left eye . Four of the subjects showed no 
su.bstantial changes in their potentials when prisms were 
ln�rcduc�d. Upon removal of the prisms, only one subject 
::;howed a significant change in his potential. 1I'hereforc, 
_:_ t w.:mld appear that indeed there are changes recorded in 
so rue individuals, whereas in. others no significant changes 
1I'he controls show that our EJViG recordings were relativeJ.;y 
�:;table over our ti.me course. 
ln conclusion, we feel that the EMG is not as reliable 
as current methods tsing·used for neutralizing vertical 
imbalance. 'I'here may be uses for the EhiG in ether areas 
of Optometry, but further investigation will be needed. 
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APPENDIX A 
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Raw data is included in the copy of our thesis housed 
at the Pacific University library, Forest Grove, Oregon. 
SU3J3CT RELYAS3 Fnny 
J.. Instj_ tution 
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BIBLIOGRAPHY 
1. Dalessio, Donald J. Wolff's Headache and Other Head Pain. 
Oxford University Press, New York. Jrd. edition, 1972, 
p. 528. 
2. Roy, Raymond H. "The Role of Binocular Stress in the 
Post-Whiplash Syndrome," American Journal of.Optometry 
and .Archives of American Academ�r of Optometry. Monograph 
294. OOinneapolis, Minn. Nov., 1961. 
J. Eckardt, L.B. , McLean, J. lVl. , and Goodell, H. "Experimental 
Studies of Headache; The Genesis of Pairt from the Eye, 
in Pain." Proceedings cf the Association for Research 
in Nervous and lViental Disear.::e. Vol. 2J, Nevt York, N. Y. 
Williams and Wilkins Co., 1943, 209-227. 
!�.. Vasilescu, :::; • a:"ld Diekmru1n, G. "Elect�omyographic 
1975. Vol. 35, 153-160. 
Coursey, Robert D. 
Journal of Consulting and Clinical 
Psychology. 1975. Vol. 4J (&), 825-8J4. 
Ycl. 90 (4), 319-322. 
gra}Jhy." Jou.r·nal of Neurosurgery. t<lay 1976. Vol. L1.!+ (j)� 
550-555. 


EMG and its possible use in the treatment of vertical imbalance

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EMG and its possible use in the treatment of vertical imbalance

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