Semi-Occluded Vocal Tract
Exercises for Voice Therapy (and
singing)
AKA –
Why we Trill, Hum,
use straws etc.
Liz Savina, Redcliffe Hospital
For Qld Voice Special Interest Group
May 2014
Overview
Definition & brief background of physics
What major therapy “programs” use it
Discuss some recent studies that show the
effects of different parameters/ on different
populations.
Demonstrations
Therapy hierarchies
Case examples
3 Major Ways of Doing SOVT
(Andrade 2014)
1. Constant frontal narrowing of the vocal tract
(nasals/glides and hand-over-mouth);
2. Lengthening (and narrowing) the vocal tract
through means of a tube (Lax-Vox/Straw).
3. Adding a 2ndry source of vibration into the
vocal tract (lip and tongue-trills, Tube into
water/fricatives).
• Been used in various forms for over 100 years
(Conroy et al. 2014)
My burning questions
• Is it guaranteed to work??
• Which types are best for
– building up vocalis (muscle within vocal cords) and
closing glottic gaps versus
– Improving retraction/deconstriction, preventing
overclosure
Why/How Does SOVT Work?
Potentially decreases
the aerodynamic
power necessary for
phonation &
optimises closure of
the vocal folds –
neither breathy or
pressed (Andrade et
al. 2014)
An entire conference on SOVT!
A little bit of the physics
SOVT (at the lips) works by…….
- Raising the mean supraglottal and intraglottal pressures
- Impedance matching by vocal fold adduction and epilarynx
tube narrowing can then make the voice more efficient and
more economical (in terms of tissue collision).(Titze 2006)
Decrease in phonation threshold pressure Reduced minimum
pressure at which the VC will vibrate
– Decreased phonatory effort
– Decreased strain
(Conroy et al 2014, Guzman et al., 2013),
The vocal fold adduction appears to be a reflex reaction.
A little bit of physics
Lowering of the first vocal tract formant (F1)
allowing the fundamental frequency (F0) of
speech to be closer to F1,
Increasing inertive reactance of the vocal tract
and producing a more efficient vocal fold
vibration pattern -> easier voicing
http://www2.psychology.uiowa.edu/faculty/mcmurray/speechglossary/
Some SOVT
• Widen the pharynx in relation to the epilarynx
-> a clustering of the 3rd, 4th, & 5th formants
(Andrade 2014) – “Singer’s Formant”
Marco Guzman,
et al Resonance
Tube and Straw
Phonation
523.e27
SOVT is used in
Stemple’s Vocal Function Exercises (nasals &
Finnish bilabial fricative)
Verdolini-Abbots – LMRVT – core part of her
Voice Therapy Spectrum – using M
LaxVox (9mm id, 25cm (Andrade) or 35 cm
(Stemple) tube in 1-5cm of water (aim for 35cm - Stemple)
Finnish Resonance Tube (soft silicone or glass
tube 25-27 cm & 9 mm id in 2-5cm of water
or free air) ~40 year hx (Paes)
SOVT is used in
• Accent Method (voiced fricatives)
• Estill Siren on “ng”, sirening
• Titze’s Straw exercise (small diameter
for men, larger diameter for women
– Titze Brisbane 2013)
• Glide loaded sentence of CAPE-V –
We were away a year ago
& S/Z ratio
Lax Vox – Stemple 2011
1 of the Big 3 things for future
voice therapy.
Lax Vox indicated for:
Stemple (2011)
Holistic therapy for various functional and
organic voice disorders:
 Muscle tension dysphonia
 Vocal fold nodules and polyps
 Habitual and psychogenic dysphonias-aphonias
(by masking proprioceptive feedback)
 Vocal fold paralysis (RLN and SLN)
 Presbyphonia
 Puberphonia
• Pre and postoperative phonosurgery
Lax Vox in Singing and Theatre voice
Stemple (2011)
 Daily voice care for all groups of voice users
 Prevention of voice problems for vocal athletes
 Developing vocal muscles with several exercises
(glissando, staccato, Messa di Voce, etc.)
 Glottal closure deficiencies
 Warming up and cooling down
 Finding and developing the optimal voice (primal
sound)
 Balancing the glottal attack
 Facilitating the lowered larynx
 Developing registers and smoothing the passaggio
Lax Vox Reference
Denizoglu I, SihvoM. Lax Vox Voice Therapy
Technique. CurrPractORL 2010, 6(2):284-295
(unable to find on Medline Ovid or Ebsco or
Pubmed or even Google!)
SOVT researched in:
•
•
•
•
•
•
Teachers (RVT and Finnish Tube)
Elderly (Finnish Tube)
Actors and singers (RVT)
“Behavioural” voice problems
Benign vocal lesions
Haven’t yet found research on Unilateral Vocal
Fold Paralysis
Some Recent Studies
http://fraukruse.wordpress.com/2013/03/07/lax-vox-voice-therapy/
Some Recent Studies
• Immediate effects
– normal speakers
– trained/untrained instructed/non-instructed
– dyshphonic/ hyperfunctional populations (tubes)
• Effect of 6 week programme on “elderly”
(tube in water)
• 24 Hours of RV
http://fraukruse.wordpress.com/2013/03/07/lax-vox-voice-therapy/
Summary of Articles will follow
Andrade et al 2014
Electroglottographic Study of
Seven Semi-Occluded
Exercises:…….Journal of Voice
Andrade 2014 SOVTE
1. LaxVox (9mm id, 25cm –? Water depth)
2. Straw (12.5 cm in length & 4 mm in
diameter)
3. Lip-trill
4. Tongue-trill
5. Hand-over-mouth
6. Humming
7. Tongue-trill with hand-over-mouth.
Procedure
Andrade 2014
N = 23 healthy volunteers
SP demonstrated and provided teaching on
error until subjects produced correctly
Asked to do same pitch for all activities.
Electroglottographic & Acoustic measures
F1 – F0
Andrade 2014
SOVT
Steady
(single source)
• Hand-over-mouth
• Humming
• Straw
with lower CQr &
F1 - F0 difference
Easiest Phonation
Andrade et al. 2014
Fluctuating
(dual source)
• Tongue-trill
• Lip-trill
• LaxVox
with larger CQr &
F1 - F0 difference
More effortful
phonation but ?
gives massage
effect
Massaging the Vocal Tract
Note the bouncing of the pharyngeal walls – easier to see
in the second half of clip when the pitch is held constant.
Tongue Trill + Hand Over Mouth
Andrade 2014
Exhibited mixed effects in both the exercise
groups
Costa et al., 2011. Immediate effects of
the phonation into a straw exercise
Costa et al 2011
N = 48, 23 with benign lesions (nodules, cysts,
polyps, and Reinke’s edema ), 25 without.
Rigid plastic straw 8.7 cm long & 1.5 mm diam
Examiner demonstrated then participants did 1
minute of straw phonation at self selected mid
range frequency and intensity.
 Videolaryngoscopy, vocal self Ax,
acoustic and auditory perception
Ax
Costa et al 2011
• Significant improvement on vocal self Ax in
patients with benign vocal lesions (p=0. 015)
but no change in patients without lesions.
• No statistically significant differences before
and after the exercise and between the
groups, in the videolaryngoscopy, acoustic and
auditory-perception assessments
Gaskill, C. S., & Quinney, D.
M. (2012). The effect of
resonance tubes on glottal
contact quotient with and
without task instruction: a
comparison of trained and
untrained voices. Journal
of Voice
Gaskill & Quinney 2012
Two groups of male participants,
 10 with no vocal training
 10 with classical vocal training,
No instruction/practice: told keep pitch
and loudness consistent
Instruction/practice: got to practice
until found best pitch and loudness and
had sense of oral resonance
Gaskill & Quinney 2012 Procedure
12 reps of a vowel-like phonation for at
least 5 seconds.
Narrow glass tube, 8 mm ID and 50 cm
Some participants needed to be cued to
not produce a humming or nasalized
sound, but to allow all of the sound to
go through the tube instead of coming
through the nose.
Gaskill & Quinney 2012 Conclusions
Resonance tube can cause immediate and
measurable changes in glottal CQ
These changes remain highly variable and
do not always fit with theoretical
predictions
does need an individualized approach that
could include trying multiple tube lengths
and diameters as well as extended and
systematic practice with larger variations
in pitch than those exhibited in this study
Guzman et al 2013 Laryngeal and
Pharyngeal Activity During
Semioccluded Vocal Tract Postures
in Subjects Diagnosed With
Hyperfunctional Dysphonia
 8 SOVT exercises:
SOVT postures
Guzman et al 2013
N=20 hyperfunctional dysphonia
8 SOVT exercises:
Blinded laryngologists rated 3 endoscopic
variables using a five-point Likert scale
 vertical laryngeal position (VLP), pharyngeal
constriction, and laryngeal compression
SOVT postures in hyperfunctional
dysphonia
Guzman et al 2013
 All semioccluded techniques produced
 a lower larynx
 narrower aryepiglottic opening
 and a wider pharynx
Compared to resting position
 VLP, A-P constriction,& pharyngeal width
changed differently throughout the 8 semioccluded postures.
 Most prominent changes were obtained with a
tube into the water and narrow tube into the
air
Lower Laryngeal Position
Straw exercises: Before (left), during (middle), after (right)
Findings:
Lower laryngeal position both during and after
Higher velum position both during and after
Hypopharynx much wider during
(Different Guzman et al., 2013, pg 523.e24 Figure 6)
Paes, et al. (2013). Immediate effects of the
Finnish resonance tube method on behavioral
dysphonia. J Voice, 27(6), 717-722. doi:
10.1016/j.jvoice.2013.04.007
Paes 2012
• 25 female teachers minimum 5-year history of
dysphonia & no prior speech therapy.
• Subjects produced 3 sets of 10 sustained
phonations with a 1-minute rest between
phonations
27-cm glass tube
immersed in at least/up
to 2 cm of water.
Results – Paes 2012
• 68% of the teachers reported increased
phonatory comfort
• 52% reported improved voice quality after
performing the exercises.
• Perceptual analysis: improved voice on counting
numbers but not on “ah”
• Spectrogram: decreased instability,
subharmonics, noise in high frequencies, and the
tendency for reduced low frequency noise on.
• Mean fundamental frequency decreased.
Dos Santos, et. al.(2014). Verifying
the effectiveness of using
resonance tubes in voice therapy
with elderly people.
Resonance Tubes in the “Elderly”
Dos Santos et al 2014
Resonance Tube Group:
Improvement in Grade, Asthenia, Strain,
Instability on GRBASI
No change in breathiness
90% self-reported improvement
Improved Vital Capacity
Improved spirometry
Resonance Tubes in the “Elderly”
Dos Santos et al 2014
 N= 42 elderly in long term care residential between
ages of 62-93 years
 30 females
 x6 1 hour weekly sessions of resonance tube,
compared to vocal hygiene ed sessions.
 Glass tubes (8 mm to 9 mm ID and 24 cm to 25 cm
length in 2-5cm of water).
 RT Therapy Rx: instructed to emit continuous sounds,
nonsensical words, and to hum the tune of “Happy
Birthday to You.”
 Rest periods of up to two minutes between emissions.
Verdolini, 2012. Vocal exercise
may attenuate acute vocal fold
inflammation
Resonant voice for treatment of vocal fold
inflammation
Verdolini 2012
 N=3 healthy males
 Used Resonant Voice
 Prospective, Randomized and double blind
 1-hour vocal loading procedure, followed
by randomization to a
 Talking as normal condition, Vocal rest condition,
RV exercise condition
 Treatments were monitored in clinic for 4
hours and continued extra-clinically until
the next morning.
Resonant voice for treatment of vocal fold
inflammation
Verdolini 2012
Results
• Complete data sets were obtained for 3
inflammatory biomarkers--IL-1beta, IL-6, MMP-8
Results were poorest at 24-hour follow-up in
the talking as normal condition
Sharply improved in the voice rest condition
Were the best in the RV condition
Summary
• SOVT exercises can optimise the closure of the
vocal folds, open the pharynx wider
• These effects tend to occur immediately
• They are not guaranteed to do so, so still need to
be individually checked – person doing should
feel a more “open throat”, less effortful voicing
and sound should improve( that’s up to our
subjective judgement)
• If SOVT improves the vocal tract configuration,
evidence shows this can then be carried over to
vowels and other speech sounds.