Dept. for Speech, Music and Hearing
Quarterly Progress and
Status Report
Physiological aspects of a
vocal exercise
Elliot, N. and Sundberg, J. and Gramming, P.
journal:
volume:
number:
year:
pages:
STL-QPSR
33
2-3
1992
079-087
http://www.speech.kth.se/qpsr
STL-QPSR 2-311992
PHYSIOLOGICAL ASPECTS OF A VOCAL EXERCISE
N i n ~ z Elliot,
i
Johatz Su~zdberg,& Patricia Gramming*
Abstract
The physiological aim of vocal exercises is mostly knowrl in intuitive terms only.
This article presents an attempt to document the phosiatory behavior induced by a
vocal exercise. An elevated vertical position of the larynx is frequently associated
with hyperfunct ional phonatory habits, presumably because it induces an exaggerated vocal fold adduction. Using the multi-channel electroglotfograph
(TMEGG) recerrtly presented by Rothenberg (1992,J. of Voice, Vol. 6), the lay n x
position was determined in a group of subjects who performed a voice exercise that
contained extremely prolonged versions of the consona?zt lb:]. This exercise is used
by coauthor NE as part of the standard vocal exercise program. Two of the seven
subjects were dysphonic phonasfenic patients while the rest were normal trained
or untrairzed persons. Different attempts to calibrate the TMEGG confirmed a linear relation with larynx height, provided a correct electrode positionirig. The results showed that the exercise induced substantial vertical displacements of the
larynx. Comparison with the larynx height behavior during other consonants revealed that the lbl in particular tended to lower the la y n x .
INTRODUCTION
The physiological goal of most vocal exercises is largely known only in intuitive
terms. For example, voice training typically includes breathing exercises aiming at
developing "support". Still, the physiological interpretation of the notion of support
seems rather vague and controversial. Such cases of lack of understanding hampers
the possibilities of development within the field of voice training.
In our time it is possible to describe in scientific terms physiological characteristics
of various types of voice uses. Thus, by means of modern instrumentation subglottal
pressure, flow glottogram, breathing behavior, and laryngeal configurations can all
be easily captured and recorded also in a clinical setting.
It is generally agreed among voice experts that the vertical larynx position is an
important aspect of voice function (Aronson, 1985; Colton & Casper, 1990). For example, singers generally use a lowered larynx position during singing, while an elevated larynx position is frequently observed in non-organic dysfunctional voices
(Shipp & Izdebski, 1975). Consequently, in such cases voice training typically includes exercises that can be assumed to aim at a lowering of the larynx.
Recently, Rothenberg (1992) presented a new tracking multichannel electroglottograph system (henceforth TMEGG). According to his findings a two channel version
of this device allows continuous, non-invasive measurement of vertical larynx position. Following the suggestion of Shipp (1975), we will henceforth refer to this measure as the VLP. The TMEGG presents a possibility to record this aspect of phonation.
The aim of the present investigation was to describe VLP effects of a particular vocal
exercise developed for pathological voices by co-author NE in her long-term experience as a voice therapist/logopedist and singing teacher.
* ~ e p tof. Phoniatrics, Karolinska Hospital, Stockholm.
79
STL-QPSR 2-3/1992
A direct calibration of VLP was attempted on subject JS, who could phonate with
different, deliberately controlled and fixed positions of his larynx. He sustained
phonations using a number of different larynx positions. The larynx positions determined from the position of the anterior gap between the cricoid and thyroid cartilages. The position of this gap was first determined by palpation for the resting position, which was marked by a line on the throat. Then, the subject phonated, and the
position of the same gap was again determined by palpation and marked with a new
line on the throat. This procedure was then repeated for all the different larynx positions.
In addition, we also carried out a simpler calibration procedure for the other subjects using a "reciprocal" method suggested to us by Rothenberg (personal communication). While the subject sustained a constant tone the experimenter alternately
slid the TMEGG electrodes on the neck 10 mm u p and down.
Subjects PG and JS also performed the complete exercise experiment at the Phoniatric Department of the Karolinska Hospital, where a video-fiberscopy documentation was carried out. The fiberscope, OLYMPUS ENF P3, was introduced paranasally after local anaesthesia, keeping the tip of the fiberscope in a position just above
the epiglottis tip. The exercise was filmed by a video camera (HITATCHI) and recorded on a video cassette recorder (PANASONIC AG 7330).
40
1
-20
20
I
-15
-10
-5
0
5
LARYNXPOSITION (mm re RESTING)
10
15
J
-20
-15
-10
-5
0
5
10
20
I
15
LARYNX POSITION (mm re RESTING )
Fig. 2. Two attempts to a direct calibration of the TMEGG signal showing VLP.
RESULT
The resting position was repeatedly checked in all subjects. Generally, the corresponding VLP value was replicated within 32 mm provided a stable electrode position.
Results from two attempts to a direct calibration procedure with subject JS are
shown in Figs. 2a and b. In both charts, the data points can be approximated with a
reasonable accuracy by a straight line, at least within a VLP variation range from -10
mm to +15 mm relative to the resting position. The lowest VLP, 16 mm below the
resting position, yielded a too high TMEGG signal amplitude to adhere the straight
line. These results are in accordance with the conclusions presented by Rothenberg
(1992); the TMEGG shows a linear relationship with VLP within a range of about +/15 mm, provided the larynx does not move too far away from the TMEGG.
Using the reciprocal method, ten calibration attempts were made in succession on
subject LN, sliding the TMEGG electrodes alternately 10 mm up and down from
various starting points on the neck. Table I shows the results. As long as the sliding
did not bring the TMEGG too far away from the level of the vocal folds (attempts 16), a reasonably constant VLP signal amplitude was obtained. Within this range, the
standard deviation was only 1.4 mm. The VLP data became unreliable, if the
TMEGG was located more than 23 mm above the resting position in this subject
(attempts 7-10). Consequently, it seemed important that the TMEGG electrodes were
carefully placed on the neck and that they were kept in this position throughout the
measurement. This may take some caution in cases where great changes of VLP occur.
Table I. TMEGG output uoltqe changes observed when the electrode
pair was slided 10 m m up or down ten times on subject LN:s neck.
The upper position of the electrodes reached in each attempt is
reflected by the rightmost column in terms of the voltage obtained for
the highest position. The resting position corresponded to a deflection
of 47 mm.
It has been demonstrated that in speech, VLP is affected by pitch and vowel, such
that the larynx generally tends to rise with rising pitch (Shipp, 1975). Also the vowel
r b:l
SUBJECT AM
Fig. 3. Comparison of V L P and
FO data for the consonant fbl
pronounced normally and deliberately prolonged by subject
A M . The V L P was related to
the resting position.
13
SUBJECT JS
\r:qg
SUBJECT LN
",
SUBJECT ST
.
SUBJECT PG
.-
b
u
I II
\.
b
I
I
SUBJECT PW
n
E
E +5-
1
I
TIME 0
SUBJECT PK
5
6)
Fig. 4a-f. VLP and FO data for the subjects indicated recorded during productions of the utterance 1b:V:b:V:l. The VLP was related to the resting position.
STL-QPSR 2-311992
Here we have selected one out of a great number of voice exercises successfully
used in everyday voice therapy. It seems advantageous to expand future investigations to other vocal exercises so as to underpin the voice therapist's intuitive knowledge by phonatory and articulatory facts, thus improving the scientific basis of voice
training.
ACKNOWLEDGMENTS
The kind cooperation of the subjects is gratefully acknowledged. This is a revised
version of a paper presented at the 21st Annual Symposium Care of the Professional
Voice, Philadelphia, PA, USA, June 1992.
REFERENCES
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Gauffin, J. & Sundberg, J. (1989): "Spectral correlates of glottal voice source waveform characteristics," ].Speech & Hear.Res. 32, pp. 556-565.
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Shipp, T. (1975): "Vertical laryngeal position during continuous and discrete vocal frequency
change," ].Speech & Hear.Res. 18, pp. 707-718.
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Sundberg ,J.(1987):The Science of the Singing Voice, N. Illinois University Press, DeKalb, IL.
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