THERAPUTIC MANAGEMENT OF
LARYNGETOMY
Introduction
The goal of
speech therapy for a laryngectomized patient is to find an appropriate source
of sound production that can be articulated for communication purposes. The most efficient and effective type of
sound source depends on:
- Degree of tissue loss, the degree of esophageal stenosis, level of hearing loss, or other physical limitations of the patient. The noise level of the environment in which the patient needs to communicate.
- The patients level of motivation in learning an alternative method of communication.
- The personal preference of the patient.
Fortunately, there are a variety of devices
and procedures that can provide a new source of sound. The patient can then use his or her
articulators to produce the sounds of speech.
There are two
general categories of sound restoration:
- Mechanical speech aids includes the pneumatic and electronic artificial sound sources.
- Alternative natural sound sources include esophageal tracheoesophageal speech, other surgically implanted prostheses and surgically created structures.
The various mechanical speech aids and voice
prostheses are discussed in the following sections
MECHANICAL SPEECH AIDS
I. PNEUMATIC DEVICES
A. Description
Pneumatic
speech devices were among the first to be used as replacements for voice
production and are still in use today.
They usually consist of a piece that fits over the stoma, a small unit
with a reed inside to provide sound, and tubing that carries the sound to the
mouth. The patient places the tube in
the corner of his or her mouth as exhalatory air from the lungs drives the reed
to produce sound that is resonated in the usual way in the patient’s oral
cavity and shaped into words by the action of the articulators. Hand held models do not require valving
mechanisms since they can be lifted from the stoma to allow the patient to
breathe.
B. Specific Types
1. Dutch speech DSPB
speech aid
In this
device, the vibrator is housed within the tubing. It is rather inexpensive (about $ 90 US).
2. Tokyo artificial larynx
This has
been described by Bloom & Mowrer & Case. This device is an inexpensive unit (about $
50.00) and is supplied with an additional oral tube, stoma cushion, and
training tape. It has been demonstrated
that patient using this device under optimal condition can achieve a 95%
intelligibility level. The modified
version consists of swivel-joint connector on the tracheostoma cover and a
mouth tube constructed of curved stainless steel tubing capped by a plastic
mouth piece.
3. Osaka artificial larynx:
It is very
similar to Tokyo
artificial larynx. It consists of a
tracheostoma cover, a vibrating reed and a mouth piece. It differs from Tokyo artificial larynx in that it is made up
of light weight plastic.
C. Advantages
The two
major advantages of a pneumatic device are that it does not have a buzzing
electronic sound and it uses the patient’s own pulmonary air supply. Phonation can be easily coordinated with
respiration and loud voice can be produced.
The patient can use his or her normal phrasing and flow of speech
without the need to turn an oscillator on and off.
D. Disadvantages
There are
several problems with the pneumatic devices.
First, they require access to the stoma for placement of the
instrument. Most patients typically wear
some kind of covering over the stoma, making access to it awkward. Second, they require the use of one hand thus
limiting the patient’s ability to perform tasks requiring the use of both
hands. Third, they are visually
distracting to the listener. Some
believe that they are a sign of patients’ disabilities rather than their
abilities. Other problems include the
lack of pitch control and the low fundamental frequency which may be a problem
for a female user.
II. Electronic Devices
A. Description
These
devices use electric power to drive a vibrator that provides the sound
source. Two versions of these devices
are available.
- Tube-in-the-mouth-type instruments: Consists of a tube attached to the electrically powered hand held transducer. The tube fits inside the mouth in much the same way as the pneumatic devices. Electronically generated sound is delivered to the oral cavity via the tube which is articulated in the normal way.
- Handheld type instrument consists of a hand held vibrator that is designed to deliver the sound through the skin when placed on the neck.
There are numerous manufacturers who produce
electronic speech aids powered by batteries.
The differences among the aids are
appearance, size, quality of sound, ability to change pitch and loudness
characteristics and the types of batteries required.
B. Specific types
1. Tube-in-the-mouth-type
instruments:
a. Cooper-Rand
Electronic Speech Aid
This device
is a battery powered sound source that directs the sound into the oral cavity
via a small tube placed in the mouth. It
is the only instrument that is designed to be used exclusively as an oral
device. Oral placement may be
advantageous immediately after surgery because the patient can use it without
interfering with neck healing or causing discomfort. The unit is lightweight (about 7 oz) and can
be carried in a shirt or blouse pocket.
An extra long cord (40 in) permits placing the device in other locations
as well, such as on a table or a bed.
The unit is controlled from the push button on the tone generator to
which the oral tube is attached.
b. Ticchioni pipe
artificial larynx:
Looks like a
smoker’s pipe with the battery attached to the base of the pipe bowl. The tone is generated in the pipe bowl and
conducted to the patient’s mouth via the pipe stem.
II. Hand held type
instrument
a. Jedcom
electrolarynx
This device
is a neck held electric sound source with a built in pitch and volume control
and a convenient on-off switch and safety cord. It is powered by a rechargeable battery.
b. Neovox
This device
is a neck held electro larynx with a single button control for volume and
contains a safety strap. It uses a
rechargeable battery.
c. Romet speech aid
This device
is a small, lightweight (5 oz), neck held electronic sound source that uses
rechargeable batteries. The unit is held
against the neck, a button is depressed to turn it on, and the sound is
articulated by the patient. The unit is
equipped with a volume control as well as a pitch control.
d. Servox Intonation
Control
This device
is an electronic, neck held sound source.
The unit is tubular and sealed in a scratch resistant case. It has an electronic volume control that
reduces power consumption and has rechargeable batteries. “intonation control”
that varies the pitch and sound of the unit during speech to permit some type
of inflection control. An intraoral
connector is also available to permit the use of the instrument immediately
after surgery or if the patient prefers to use it in this manner.
e. SPKR
This device
is another electronic, hand held sound source that is placed against the neck
to direct sound through the skin into the vocal tract. It features a dual tone rocker switch to
volume control, an external pitch adjustment and an oral adaptor. It uses rechargeable batteries and has a
safety strap.
f. Western Electric
Artificial Larynx
It is the
most popular one and is available in models that are pitched differently for
males (model 5B) and females (5A). This
device is a neck held, 9 volt battery powered device. It is lightweight, can be carried on a pocket
or purse, or hung around the neck. The
unit is activated by a single switch controlled by the patient’s thumb. This is probably the lowest priced unit
available (under $300), and it offers pitch and volume controls.
Advantages
The major
advantages of the electric powered speech aids (and to some degree the
pneumatic devices) is the ability to offer a rapidly learned means of
communication. The devices can be
demonstrated prior to surgery and require little effort to use immediately
after surgery. They are easily
portable. Some permit a limited ability
to vary the fundamental frequency (FF) of the voice during speech to achieve
some measure of pitch inflection. Many
are available with an intraoral adapter.
The adapter fits over the membrane or vibrator and usually uses a small
plastic tube to direct the sound into the vocal tract. This adapter permits the use of the
instrument immediately after surgery when the neck wound is healing. Patients experience an immediate restoration
of their ability to communicate. After
wound healing is complete, patients may use the device in either manner, for
example, against the skin of the neck or as an oral unit.
D. Disadvantages
All of these devices tend to produce a mechanical
sound that may be distracting to a listener and may interfere with
communication. Most require the use of
one hand, limiting the ability of the patient to use both hands when
talking. Most have very limited control
of fundamental frequency which limits normal pitch inflection of the patient’s
speech. In addition, it may be
cumbersome to use the pitch altering mechanisms that are available. There are some operating expenses, because
the batteries wear out, and mechanical devices may need occasional repair.
Indications for use
1) An oral type of instrument can be used effectively soon
after surgery, regardless of the type of alaryngeal speech the patient will
choose to pursue.
2) An electronic speech aid may be a preferred primary means
of communication for some persons.
Patients who are elderly and infirm and whose life style involves
minimal communication may choose an instrument.
3) A person who is very eager to speak and cannot tolerate
the frustration or demands for practicing of esophageal speech may be happy
with an instrument.
4) The person who cannot master esophageal speech and does
not wish to undergo further surgery may choose to use an electronic instrument.
5) All laryngectomees should have an instrument and know how
to use it as a backup or insurance policy in case of emergency.
ALTERNATIVE NATURAL
SOURCES
I. ESOPHAGEAL SPEECH
A. Description
Esophageal
speech involves the production of a voice source within the esophagus using air
supplied by the patient. The esophagus
is a muscular tube that begins just behind the larynx. The most inferior portion of the inferior
constrictor muscle, called the cricopharyngeus, extends from the cricoid
cartilage to insert on portions of the pharynx posteriorly and into the
esophagus. Surgeons attempt to leave
this muscle intact during laryngectomy so it can be used to constrict the
esophagus and permit the trapping of air inferiorly. When the air is expelled through a narrow
constriction in the esophagus created by the cricopharyngeus muscle, the
narrowed segment (the pharyngeal esophageal or PE segment) will vibrate,
producing sound. The patient has the
capability of producing periodic sound at the beginning of the vocal tract
similar to that produced in normal speech.
B. Anatomy of
esophageal speech
Surgical alterations
Surgery for
laryngeal carcinoma may involve only the larynx itself (and associated
extrinsic muscles), or it may require the extirpation of other structures and
muscles in the neck. In the simplest
case, the patient may have lost only the larynx. This means, of course, that the source of
sound for speech is missing. The larynx
and the hyoid bone are typically removed during a routine laryngectomy. The trachea is sutured to the front of the
neck where a permanent opening called the tracheostoma is created. On the left are the normal anatomical
relationships among the larynx, esophagus, pharynx and oral and nasal cavities. On the right are the surgical alterations to
this anatomy. There are, of course,
little or no surgical changes to the esophagus during the procedure. However, esophageal speech depends on the
ability of the esophagus to constrict at a region. This region is known as the pharyngeal
esophageal segment (or simply the PE segment).
PE Segment
This
refers to that portion of the pharynx
and esophagus where muscle fibers fro the inferior constrictor, cricopharyngeus
(or the lower portion of the inferior constrictor), and the esophagus blend
together. This creates a potential
sphincter that can decrease the cross sectional area of the esophagus. Although most of the esophagus is composed of
muscle fibers not under voluntary control, the muscle fibers in the upper
portion of the esophagus are under voluntary control. Thus, an individual can
exert conscious control of the upper esophagus.
The cricopharyngeus muscle extends posteriorly from the cricoid
cartilage of the larynx and blends with the muscle fibers of the
esophagus. During surgery for a laryngectomy,
the anterior fibers of the cricopharyngeus are sutured together, creating a
complete muscle sphincter around the esophagus.
The shape and length of the PE segment varies depending on the exact
surgical alterations to the anatomy of the region. However, shape or size of the PE segment does
not appear to be factors in predicting successful acquisition of esophageal
speech. Of even greater importance is
the degree of tonicity of the segment.
If the resistance of the PE segment to dilation or oscillation is high,
it may be difficult for the patient to insufflate the esophagus to produce good
esophageal vibrations.
Air Supply
Esophageal
speakers have a much lower air reservoir (less than 100 cc) than is available
to laryngeal speakers from the lungs (>5 liters). However, efficient esophageal as well as
laryngeal speakers typically require a very small amount of air to produce
vibration. The small air supply will
limit the esophageal speaker’s ability to produce long utterances on a single
charge of air.
Air flow
rates are also somewhat variable in esophageal speakers and depend on:
·
the volume of air in the esophagus
·
the pressure within the esophagus, and
·
the resistance of the PE segment (Diedrich,
1991)
Air discharge
Air is
thought to be expelled from the esophagus as a result of mechanisms similar to
exhalation of air from the lungs. That
is, increased thoracic pressure creates a force on the esophagus (which passes
through the thorax on its way to the stomach).
The esophageal walls within the thorax are constricted forcing the air
within to move up the esophagus and out them out. Interestingly, there is evidence (Kahrilas et
al. 1986) that in laryngeal speakers, during a belch, the pressure in the upper
portion of the esophagus is lower than in the lower portion of the
esophagus. This suggests that the
resistance to opening the upper portion of the esophagus is less than the lower
portion, permitting easier release of air upward into the pharynx rather than
downward into the stomach.
C. Techniques for
obtaining an air supply
1) Injection
In this
method, air injected from mouth into esophagus via the tongue and pharynx. The tongue acts like a piston to force air
back into pharynx and esophagus. There
are 2 stages in this sequence.
First, the tongue
pushes the air into in the mouth back to the pharynx (the so called glosso
press).
Second, the
back of the tongue and pharynx force the air down into esophagus
(glossopharyngeal press).
a) The glossal press
is produced by the tongue tip contacting the alveolar ridge. The midportion of the tongue may elevate to
contact the hard palate. Air is trapped
behind the tongue and moved posteriorly by the backward movement of the tongue. The tongue does not make actual contact with
the posterior pharyngeal wall. However,
the soft palate is elevated to prevent escape of the air through the nose. The lips may or may not be closed because the
tongue tip traps the air needed for injection.
b) In the glossopharyngeal
press, tongue movement is similar to that seen in the glossal press, but
the tongue continues to move backward to contact the pharyngeal wall. Again, velopharyngeal closure is necessary,
but lip closure is not. Tongue and
pharynx force air down into esophagus.
2) Inhalation Method
It is based
on the principle that air will enter the esophagus if the PE segment is
sufficiently relaxed when pulmonary inhalation occurs. To accomplish this, the patient must be able
to relax the PE segment; otherwise, air cannot flow downward. Typically, the intraesophageal pressure is
between -4 and -15 mm Hg (Diedrich, 1991) below atmospheric pressure. When the PE segment opens, air in the mouth
and pharynx which is typically at atmospheric pressure (+14 mm Hg) will
naturally flow from the region of higher pressure to the region of lower
pressure, that is, in the esophagus. The
reduction of pressure within the esophagus is a by-product of the normal
inhalation of pulmonary air. That is,
when the speaker inhales air, the pressure within the esophagus becomes even more
negative relative to the atmosphere (as much as -15 mm Hg), creating an even
greater sucking force to pull the air into the esophagus).
3) Swallowing
At one time
or another, each of us has swallowed air into the stomach and has, at a later
time, burped. But, swallowing air is not
advantageous for creating an air supply for esophageal speech for a variety of
reasons.
a)
Swallowing is a reflex that requires a bolus of some
type to trigger the reflex action. In
the absence of a trigger it is often difficult to initiate a swallow.
b)
It is not possible to dry swallow quickly and
repetitively as required for speech.
c)
Voluntary control of the air supply from the stomach
may be very difficult to achieve, if not impossible.
4) Consonantal
injection:
It is an
efficient method of getting air into the esophagus as it allows air to be
injected in to the esophagus during intra phrase intervals as well as during
rest unlike other methods. Because air
can be injected when the tongue is positioned for releasing a consonant of
word, air for subsequent esophageal production is usually injected into the
esophagus simultaneously with the release of articulator. Teach the patient to produce intraoral
whispers of plosive consonants (p); patient should be able to feel the compressed
air inside the mouth moving towards the throat during the production of
sound. Once the patient is able to
produce crispy /p/ ask him to produce other plosives, fricative and affricates
followed by monosyllables and polysyllables with pressure consonants.
E. Advantages
Esophageal
speech may offer a number of advantages over other forms of communication.
·
There are no external, visually distracting
devices necessary.
·
The sound of esophageal speech is more “natural”
and nearly like that produced by the vocal folds (although usually of much
lower fundamental frequency).
·
The patient is able to achieve some measure of
pitch and loudness control and good esophageal speakers are able to vary these
dynamically during speech.
·
There are no batteries that run down or devices
that break down.
·
Both hands are free during the speech act.
F. Disadvantages
1) Grimacing and
excessive body tension: Patients may
clench his lips tightly together, produce unusual facial contortions or bend
head during insufflations.
2) Excessive stoma noise due to forceful movement of air
through stoma during inhalation of exhalation which competes with the
esophageal speech intensity.
3) Klunking and other extraneous noise when attempting to
forceful injection of air using glossopharyngeal press or swallow method.
4) In the course of insufflating the esophagus a certain
amount of air is swallowed into the stomach.
Patients will complaint of bloated feeling and frequent burps.
5) Esophageal speech must be learned and may take a long time
to master. Some patients may never learn
to produce functional esophageal speech even after much effort.
6) A person’s ability to articulate clearly must be
excellent; otherwise the intelligibility of esophageal speech may be poor. The patient may have difficulty being heard
above background noise. There are speech
amplifiers (Voicette, rand Voice Amplifier, or AddVox (Figure 4-7) see Appendix
B) that may increase loudness but these must be carried with the patient and
may be visually distracting.
I. Indications for use
of Esophageal Speech
1) Most patients are potential esophageal speakers. The exceptions to this might be patients with
extensive pharyngeal, esophageal, lingual, and / or mandibular resection;
patients whose medical status is otherwise compromised, patients with
significant hearing loss patients who have chosen to have a
Tracheoesophageal fistulization and
patients who have no desire to learn esophageal speech.
2) Patients can use esophageal speech and electronic speech
aids interchangeably, depending on the environmental noise level or situation.
3) Teaching Esophageal
Speech
The teaching
of esophageal speech requires skill, understanding of the anatomy and
physiology of esophageal sound production, patience, sensitivity to the
psychological impact of the process on the patient, and the ability to be
supportive. It is extremely helpful for
the clinician to have acquired the ability to produce esophageal sound. Often demonstration of its production can be
more instructive than verbal explanations.
For the
patient, the learning of esophageal speech requires a high degree of
motivation, a willingness to learn to produce a sound voluntarily that has
always had a negative stigma, patience, the physical integrity necessary to
produce esophageal sound, emotional stability, and a host of other factors that
are difficult to itemize.
There are a
variety of methods for teaching patients and the following sections are based
on clinical experience with methods that have proven effective as well as discussion of less successful methods.
·
The clinician should listen carefully for any
involuntary production of esophageal sound.
Some patients will inflate or charge the esophagus unconsciously as they
attempt to produce whispered speech.
Even if the clinician does not hear evidence of such sounds during the
first session, patients should be asked if they have made any sounds
involuntarily since their surgery, and if so, to describe when it happened.
·
Ask the patient to make a burping sound. It is always good for the clinician to be
able to demonstrate production of a “burp”.
This may make the patient more comfortable about producing a sound that
has been considered socially unacceptable.
Some patients will be able to produce such a sound with ease. The clinician should carefully observe the
manner in which the patient attempts to produce the burp, whether successful or
not. It is especially important to note
whether the patient is working hard at swallowing during the attempt. If that is the case, it is a behavior that
should not be encouraged or reinforced.
If the patient seems to be injecting air into the esophagus
appropriately and producing sound, the clinician should continue with
additional trials during which the patient’s attention is directed at
determining how the sound is being produced.
·
The clinician should demonstrate injection of
air in an audible manner and ask the patient to produce a similar sound. The sound is typically referred to as a
“klunk”, and should be audible but not excessively loud.
·
Try to trigger esophageal sound production using
plosive consonants.
·
The patient can learn to manipulate the air
trapped in the mouth by puffing the cheeks out and by moving the air around in
the mouth from side to side and forward.
·
In addition to using the voiceless stop
plosive/vowel combinations noted above to trigger esophageal sound production,
there are a number of words that often trigger sound production.
·
As a last resort, after having tried and retried
all of the above methods to teach injection, the “idea” of swallowing in a
controlled way may be introduced.
·
Extending sound production into speech early in
the process is helpful to patients, but should not be rushed.
II. GASTRIC SPEECH:
A successful
pharyngolaryngoesophagectomy with pharyngogastric anastomosis – the so-called
gastric pull-up-surgery-involves a variety of postoperative functional
alterations, including alimentation and speech.
Surgical procedure
Under
general anesthesia, a secondary TG fistula was created, using a Groningen tracheal
puncture forcep. With the patient in a
supine position, a rigid esophagoscope was placed into the cervical stomach via
the oral cavity. The esophagoscope was
turned 180 degrees to expose the beveled edge toward the penetration site,
which was within the visible lumen of the stoma. Considerable force was required to puncture
through the gastric wall. Immediately following the puncture, the voice
prosthesis was inserted. The fistula
site was placed at the level of the inferior margin of the stoma.
Disadvantages:
Although the
problems involved in solving the postoperative difficulties of swallowing and
digestive processes have been discussed extensively restoration of voice and speech in these patients has been
largely unsuccessful. For example, of
the 136 cases of gastric pull-up
performed at the Queen Mary Hospital in Hong Kong, speech rehabilitation was highly unsatisfactory, with only 9
patients (6.6 percent) able to produce audible whisper, and 6 patients (4.4
percent) able to use an electro larynx.
This occurred despite the fact that 87 percent of patients satisfactory
alimentary.
Functions,
Nonetheless, speech restoration for all types of pharyngeoesophageal reconstruction was not considered to be
satisfactory, and involved single word utterances or was achieved only with the
aid of an electronic device. Although
better speech quality
Was obtained for the gastric pull-up group than for the other
categories, since these patients were able to inject air transorally and
generate neoesophageal sound, the
functional scores for speech were still poor.
Of the 101 gastric pull-up surgeries performed in England by Harrison and his colleagues, acquisition an adequate
voice was possible only in a small number of patients, in contrast to the
number who regained trouble-free eating ability. Patients who were able to produce voice did
so by manual compression of the cervical
stomach, or when experiencing pharyngogastric fistulas.
III. VOICE USING
SURGICALLY CREATED STRUCTURE OR SURGICALLY CREATED PROSTHESIS
A. Description
The
rationale of these approaches has been that a patient who is given replacement
of excised vocal folds would then be able to use pulmonary air to speak
effortlessly soon after surgery without the necessity for extensive speech
training.
B. Types:
1) Tracheoesophageal air shunt approaches:
Modern
interest in surgical reconstruction of laryngectomized patient began in the
late 1950s for shunting air to the esophagus for the production of voice. Although these techniques resulted in the
production of a satisfactory voice, the procedures were discontinued because
patients frequently experienced a leakage of fluids of esophagus into the
trachea via the shunt during swallowing and because it was difficult to
maintain the airway due to stenosis.
2) Asai Technique:
It is an
early attempt to surgically create a tracheoesophageal air shunt and a vibratory source for voicing
purpose. The multi-staged surgical
procedure consisted of connecting the trachea with the hypo pharynx with a dermal tube. To phonate, the patient would occlude the stoma with a finger and
pulmonary air would force through the dermal tube and into the hypo pharynx,
causing the pharyngeal end of the tube to vibrate. Although the voice produced was adequate,
many patients experienced problems like tube stenosis and air growth on dermal
tube.
3) Air bypass
approaches:
Here
surgery is done to design a method by
which pulmonary air from the tracheostoma can be diverted via a chest-mounted
or neck-mounted air shunt into the esophagostoma that has been surgically
created specifically for this type of prosthesis. The method by which voice produced would on
which type of air bypass prosthesis is used.
4) The staffieri
approach:
Developed by
Staffieri, this approach consists of
creating a muscle and mucosal neoglottis between the trachea ands the
esophagus. This procedure needs frequent
surgical revisions to prevent closure of the neoglottis.
5) Tracheoesophageal fistulization / puncture:
Tracheoesophageal fistulization / puncture is a surgical
procedure in which a small puncture (fistula) is made through the tracheal wall
into the esophagus. The surgery may be
performed at the time of the laryngectomy, or it may be performed at a later date.
It is a relatively simple procedure and is relatively free of any major
complications. The opening allows the
insertion of a prosthesis that acts as a conduit, or shunt to direct the air
into the esophagus. This air moves up
through the PE segment and in so doing creates sound. The sound in the esophagus travels into the
pharynx and oral and nasal cavities where it is resonated and articulated to produce speech.
a) Description of Surgical Procedure
Tracheoesophageal fistulization puncture may be performed under
general or local anesthesia, and a puncture or fistula of the
Tracheoesophageal wall is surgically
created. Maintaining this surgically
created fistula until it has healed is accomplished by placing a catheter
through the puncture site. The catheter
is subsequently removed by the surgeon or speech-language pathologist at the
time of the fitting of the voice prosthesis.
b) Voice Prosthesis
The voice
prosthesis is a short length (1.8 – 3.6 cm) of medically sage material (usually
silicone) with a valve (slit or hinge type) at the distal end. The anterior or front and has an opening
through which pulmonary air enters, and a small collar separates that part
which is inserted into the esophagus from that which is in the trachea.
Air
pressures required to force open the slit range between 2 and 25 cm H2O and
depend on the rate of airflow from the lungs and the type of device used
(Weinberg & Moon, 1984). Some
patients may have considerable difficulty producing these pressures. In these cases, lower resistance prosthesis
may be suitable, allowing for greater ease of sound production.
c) Mechanisms of
TEF/TEP Sound Production
·
To produce sound with the voice prosthesis in
place, the patient uses his or her own air supply from the lungs. To do so, the patient occludes the stoma,
usually with a finger or thumb, and inhales.
Air from the lungs enters the prosthesis and is released into the
esophagus through the slit. This air
passes through the PE segment where sound is produced.
·
The sound produced enters the oral cavity where
it is articulated and shaped into words.
With practice, the patient learns to produce complete sentences with
normal rate and phrasing. Special valves
are available to eliminate the need to occlude the stoma manually. These valves close automatically when greater
than normal thoracic pressures are present as when, for example, the patient
wishes to produce speech.
C) Advantages
This
technique can provide the most rapid restoration of near normal speech for most
laryngectomized patients. After normal
healing has been complete, the prosthesis can be fitted easily by the physician
/ speech pathologist team. After
appropriate instruction, the patient should be able to remove and reinsert the
device. The prosthesis is inexpensive
(less than $ 20.00) and is available in a variety of sizes to accommodate
variations in stoma size ands fistulae size.
The other
major advantage is that normal pulmonary air is used t drive the PE segment,
freeing the patient’s hands and permitting near-normal speech production. Experience with surgical prosthetic voice
restoration has demonstrated a very high success rate in the acquisition of
functional speech.
D. Disadvantages
1) As with any surgery, there are risks. The possibility of complications that may compromise
the airway or the fistula is present.
2) Occasionally, the fistula may stenose, preventing the
insertion of the device. This usually
occurs if the fistula has been allowed to remain totally unstinted or if the
prosthesis has been improperly fitted.
3) There is a slight risk of aspiration of the prosthesis if
it becomes dislodged from its placement.
4) Other complications include stoma stenosis, infection due
to poor hygiene, radiation-induced fistula closure, granulation buildup,
prolapse, or leakage around the prosthesis with subsequent aspiration.
E) Teaching Tracheoesophageal
Speech:
a) Patient Selection
Patient
selection for primary fistulization is often determined by the surgeon, who is
primarily concerned with the success of the surgery and the fewest
complications. The speech-language
pathologist should ideally be involved in selecting. TEF patients and should consider the factors
discussed below (with the exception of esophageal insufflation testing).
·
Healing from previous surgery should be
complete.
·
Radiation treatment or other forms of treatment
should have been completed.
·
The patient should have had an adequate interval
of being free of disease.
·
The patient should be medically stable in areas
other than the laryngectomy. Patients with
major respiratory problems must be carefully assessed to ensure they will have
adequate air volume and adequate ability to generate air pressures required to
move the air through the prosthesis and generate sound.
·
The tracheostoma must be of adequate size (1.5
cm minimum) to house the prosthesis, and it must be above the jugular notch at
the manubrium. If the stoma has a
tendency to close, the patient may need to be fitted with a prosthesis that is
built into a tracheostoma tube.
An excessively large stoma may be difficult for the patient to occlude
with the thumb.
·
There must be a healthy common wall between the
trachea and the esophagus.
·
The patient should display emotional stability
sufficient to undergo another surgical procedure followed by fitting of a
device and training in its use.
·
Dependence on drugs or alcohol would serve to
eliminate the patient from consideration.
·
The patient’s should display a degree of
motivation sufficient to follow through with the full program of voice
restoration.
·
The patient’s
eyesight, manual dexterity and control, habits of general hygiene and
general alertness must be considered.
·
The prospective candidate for TEF, having passed
all of the above tests, should then have insufflation testing. This procedure is within the scope of
practice of the speech-language pathologist who has the appropriates
competencies. This involves the
transnasal insertion of a rubber catheter into the esophagus, introduction of
air through that catheter, and production of sound. A judgement of the adequacy and quality of
the sound that is elicited must be made.
b) The Blom-Singer
Insufflation Test Kit is available and includes complete instructions for
its use. The test kit contains a
measured section of 14 Fr. (French) red rubber catheter attached to a
tracheostoma adapter and housing. This
is affixed to the stomal area of the neck.
The catheter must be passed transnasally as far as the marker at the 25
cm point, which should rest at the nasal tip.
If the catheter is not inserted up to this marker, the test may be
invalid. With the catheter and the
stomal housing in place in patient is instructed to inhale, to cover the stoma
adapter with his or her finger, and thus, to self-insufflates the esophagus. The patient should be able to produce sound
easily. Ideally, production of a vowel
should be sustained for 8 sec. or longer, and the patient should be able to
count to 15. The patient must attempt
easy sound production without excessive strain and tension. He or she should neither swallow air nor
attempt to pump air in. Either maneuver
will not allow the pulmonary air to be released. When the initial test is unsuccessful,
repeated trials may be needed.
Unsuccessful
insufflation testing should lead to referral for further exploration of the
cause for failure. This may involve a
videoradiographic study and / or injection of lidocaine to produce a pharyngeal
plexus nerve block that induces relaxation of the PE segment.
Preoperative
recording of intraesophageal peak pressure levels have been proposed by Lewin,
Baugh, and Baker (1987) as a procedure that can predict the success of
fistulization more objectively. It
reported to be more than 90% accurate.
Patients found to have intermediate or high intraesophageal pressures
required myotomy to become fluent tracheoesophageal speakers.
c) Fitting of the
Voice Prosthesis
·
The timing for fitting the voice prosthesis may
be different for each patient. For the
patient with primary TEF (at the time of surgery) fitting of the prosthesis may
be delayed for as long as 3 weeks or until surgical sites show adequate
healing. Fitting of the prosthesis for
the patient with secondary fistulization (after the primary surgery) may take
place anywhere from 36 hours to 1 week or more after the procedure. The fistula must be healed well prior to the
fitting.
·
To remove the red rubber catheter, it may be
necessary to remove the sutures that were put in at the time of surgery. The area must then be carefully cleaned, and
a clean catheter is reinserted and may be held in place by tape. Whenever a catheter or prosthesis is not in
place, the patient is cautioned not be swallow.
This should not occur for more than seconds at a time.
·
To test the phonatory mechanism with the least
possible resistance, ask the patient to inhale, occlude the stoma, and
exhale. This should result in sound
production. A few trials may be
necessary. If no sound is produced after
several trials, the catheter should be replaced, or a dummy prosthesis may be
used, and the fitting should be postponed for a few days to allow more time for
healing and reduction of swelling.
·
A sizing device, available from the
manufacturers, is used to measure the length of the prosthesis required. The catheter is removed and the measuring
probe is inserted. It is possible to
feel when that probe impinges on the posterior pharyngeal wall. The clinician should gently retract the probe
until the flange is at the anterior esophageal wall and resistance to further movement is felt. At that point where the sizing device is
comfortably within the esophageal lumen, neither abutting against the posterior
esophageal wall nor too snugly pulled against the anterior esophageal wall, the
measurement should be taken. It is
better to measure too long than too short in this early stage of sizing. If it is too short, the surgically produced
track may begin to close. It is
sometimes helpful to leave the instrument in place for a minute or two to see
what happens to the position of the prosthesis when the patient swallows. On occasion, the probe will be pushed forward
slightly by the swallow. It may be more
comfortable for the patient to fit the prosthesis allowing for the adjustment
as long as the prosthesis is in the esophagus and is sufficiently long to
maintain an open tract. The anterior end
of the prosthesis should lie fairly flush against the puncture aperture.
·
If the prosthesis cannot be inserted easily, the
lumen of the fistula may be tight and require easy dilation. Catheters of increasing dimension may be used
to dilate the fistula. This should be
done gradually and carefully to allow for ease of insertion as well as a well
fitting seal around the prosthesis.
·
Insert the prosthesis using the insertion tool
to demonstrate the process to the patient.
The patient is instructed to attend to the sensation when the collar
flange is released in the esophagus. The
outer flange or strap is released from the insertion too, and the tool itself
is gently rotated as it is pulled forward and removed. Tape the outer strap to the neck.
·
With the prosthesis in place, check for any
signs of leakage around the fistula by having the patient swallows small
amounts of water or other liquid.
Observing the swallow with a light directed into the stoma should make
it possible to detect leakage. If it is
noted, the patient will need to allow further time for the puncture to close
down around a 14 Fr catheter. If leakage
occurs through the prosthesis itself, a new prosthesis should be inserted.
·
The patient should then be instructed to inhale
and attempt to phonate while the clinician occludes the stoma. It is important that the entire stoma be
occluded but that the pressure against it is gentle. On these initial trials, it is not unusual
for the patient to inhale too deeply thereby over inflating the esophagus, or
not activate the airflow correctly due to excess tension. Either of these will inhibit the production
of sound.
·
The patient should then be taught to occlude the
stoma. If the stoma is too large for the
patient to be able to occlude digitally, creative ingenuity must be used to
solve this problem. For example, the
housing and the stoma adapter that come with the insufflation kit can be used
to removing the catheter and plugging the attachment port. The housing is affixed to the peristomal area
as it would be for the insufflation test.
·
The patient is now ready to attempt speech by
inhaling, occluding the stoma, and producing either a sustained sound or words,
such as counting. When patients are
successful in this, they are instructed to practice frequently throughout the
day. As the patient becomes comfortable
with the device and proficient in the act of occluding the stoma, the speech
usually becomes increasingly fluent and effortless.
·
Removal and reinsertion of the prosthesis must
be learned properly. Although it may not
be necessary for the patient to remove the prosthesis until a return visit to
the speech language pathologist or doctor, he or she should know how to remove,
clean, and reinsert the prosthesis or a dummy prosthesis or the red catheter,
should it become necessary to do so.
This should be taught in a slow, step-by-step process.
1) Arrange
a clean, well lit area with a mirror and the equipment required.
2) The
patient is instructed to remove the prosthesis by firmly pulling it forward by
the outer flange or strap. It must be
remembered that, if the prosthesis is to be out for any period of time, the
catheter or a dummy prosthesis must be inserted. The patient is shown how to do this and given
the opportunity to practice.
3) The
prosthesis is cleaned according to manufacturer instructions.
4) The
patient is then shown how to place the prosthesis on the insertion tool and is
given the opportunity to do this.
·
Patients undergoing radiation therapy after being fitted with prosthesis may find a
temporary disruption in their ability to speak during the course of the
radiation treatments because of swelling and inflammation of the tissues. Speech should return naturally as those
problems resolve.
·
Candida
deposits on or in the prosthesis may interfere with sound production. A solution for this involves having more than
one prosthesis, changing prostheses every day or two, and soaking one
prosthesis in hydrogen peroxide.
·
Granulation tissue formation may occur as a
result of inflammation associated with infrequent prosthesis removal. The obvious solution to this problem is more
frequent removal and cleaning of the prosthesis.
·
Difficulty in producing voice that occurs after
a time of initial success may have a number of causes. The prosthesis valve should be checked to
make sure that it is not stuck. If the
prosthesis was incorrectly fitted and is too short, or if it was not fully
inserted, secondary tract closure may have occurred. This will require dilation of the tract and
reinsertion of a longer prosthesis.
d) The Tracheostoma
Valve
The
tracheostoma valve eliminates the need for digital occlusion of the stoma for
speech production. Patients must be
selected and fitted appropriately with the valve. The design of the valve allows quiet
breathing to be unimpeded. A thin
diaphragm responds to the natural increase in air pressure for speech by
closing. There is a flexible housing or
collar (similar to that used in the insufflation test) which must be sealed on
the peristomal skin. This is done with
the use of double-faced tape and a
liquid adhesive. A tight seal is
essential for the valve to function. The
valve is inserted into the housing and can be quickly removed. If necessary, leaving the housing in
place. Patients with significant
respiratory problems may not be good candidates for use of the valve. Similarly, patients who experience excessive
mucous discharge and secretions find the valve problematic. All other patients should be given a trial
with the valve to determine its efficacy for them.
1)
Patients should be speaking effectively using digital
stoma occlusion before the valve is attempted.
2)
The peristomal area should be clean and dry. The prosthesis should be place. The outer strap of the prosthesis should be shortened
by approximately ¼ in. prior to its insertion.
3)
The double-sided tape or a foam disc is affixed to the
housing. The liquid adhesive is spread
thinly around the stoma and allowed to dry before affixing the housing. This is often the most troublesome part of
valve fitting. Unless the neck around
the stoma is flat and smooth which is rarely the case, an attempt must be made
to fit the flexible housing so that it fits the neck contour. Because of the frequency of this problem,
foam discs are now available that can be helpful in counteracting the
irregularity of the neck anatomy (See Appendix C for a list of suppliers). The opening of the housing should ideally be
slightly below the lower edge of the stoma.
It is necessary to seal the contact between housing and skin manually,
or with the use of a blunt ended instrument, rubbing firmly around the
housing. All air bubbles must be pressed
out.
4)
The valve is inserted into the housing. Valves with three different weights have been
available. Each required slightly
greater air pressure to close. More
recently, a single variable weight valve has been designed that can replace the
previous individually weighted valves.
When the valve is in place, the patient should be allowed to sit quietly
briefly to be reassured that breathing is unimpaired.
5)
The patient is then instructed to produce easy speech
using a quick exhalation to close the valve.
If the housing seal is firm, the valve diaphragm should be head to close
and speech should be produced. If the
diaphragm does not close, make certain that air is not leaking around the
housing. Allow the patient several
trials. It may be necessary and
advisable to use a low pressure
prosthesis when using a valve.
The valve must shut easily for speech yet be sufficiently resistant to
remain open during increased physical exertion.
6)
As with the prosthesis, the patient must be instructed
in affixing the housing and inserting the valve. The latter is particularly.
7)
Important because of the need to remove the valve during
or after coughing, or at any other time that it may need cleaning. It is important that patients grasp the outer
edge of the valve to remove it and not the bar that may go across the top. The function of that bar is simply to keep
clothing away from the valve.
8)
Patients may need short-term therapy to lean to use the
valve effectively. Attention should be
given to easy speech production with minimal strain, length of utterances
consistent with pulmonary air supply, appropriate phrasing, and good coordination
of exhalation and speech.
Advantages and
disadvantages of each form of alaryngeal speech are presented in Table. The various mechanical speech aids and voice
prostheses are discussed in the following sections
Table: Comparison of
alaryngeal speech modes
Type of speech
|
Advantages
|
Disadvantages
|
Pneumatic speech aid
|
Natural non electronic sound, easy to learn, intelligible
speech inexpensive operating cost (no batteries)
|
Bulky size, requires access to stoma, sometimes difficult
to maintain seal at stoma
|
Electronic speech and (neck type)
|
Easy to learn, fits in pocket or purse, volume and pitch
controls for individual preference.
Adequate volume to be heard in noisy places, intelligible speech when
used well.
|
Noisy electronics sound, cannot be used with heavily
scanned or erythematous neck, moderate initial cost, low operating cost for
renewed batteries, occasional extra cost for repair, requires very clear
articulation skills.
|
Type of speech
|
Advantages
|
Disadvantages
|
Electronic speech aid (oral type)
|
Easy to learn to use, fits in pocket or purse but may be
larger than neck type, volume and pitch controls for individual
preference. Adequate volume to be
heard in noisy places, may be less noisy than neck types, can be used soon
after surgery evening presence of much scar tissue, intelligible when used
well.
|
Electronic sound very obvious to all observers “clumsy”
feeling initially to talk with tube in mouth, moderate initial purchase cost,
occasional additional cost or repairs, requires very clear articulation for
easy intelligibility.
|
Esophageal speech
|
Natural non-electronic sound, requires no dependence on
mechanical instrument or other device, sound of the voice does not call
attention to itself (may be perceived as having a child)
|
A period of therapy required for most people, may be
difficult for one third or more of patients to learn well enough to be easily
intelligible, difficult to hear in noisy environments, requires excellent
articulation skills, and may exacerbate symptoms of hiatal hemia condition.
|
Type of speech
|
Advantages
|
Disadvantages
|
Tracheoesophageal speech
|
Natural non-electronic sound requires short learning
period, smooth, fluent speech using long sentences because of availability of
pulmonary air, smooth, clear sound for most patients, flexibility of loudness
and pitch variations, and sound of voice does not call attention to itself.
|
If not done as primary procedure, requires another surgical
procedure, requires maximum manual dexterity, visual activity and levels of alertness
to care for, requires use of finger to occlude stoma or daily affixing of
valve to peristomal area, occasional aspiration due to poorly seated
prosthesis, or poorly functioning prosthesis, buildup of Candida deposits
requiring frequent cleaning may need to remove valve when coughing or to
clean after coughing.
|
THERAPY:
General Considerations:
A few broad
areas apply to all alaryngeal speech modes; however, some are most relevant to
the learning to esophageal speech. These
include initiation of therapy, group versus individual therapy, frequency of
therapy, involvement of family and / or friends in the therapy session,
practice and pace of therapy, prognostic factors, and when to terminate
therapy. Issues of reimbursement are too
complex and changeable to be discussed here.
A. Timing of Speech
Therapy
1) We advocate the earliest possible initiation of speech
therapy. Patients are strongly
encouraged to begin speech therapy as soon after discharge from the hospital as
possible. It is important for them to
begin the rehabilitation process promptly because the longer the time between
the surgery and the beginning of therapy, the poorer are the prospects for a
good result. Many patients will have to
undergo a course of radiation therapy, a difficult period often lasting 5 to 6
weeks. Many have physical reactions to
the radiation treatment that may retard or interrupt the process of speech
therapy during that time. It is important
for them to have acquired some form of communication (other than writing) prior
to radiation. Furthermore, lack of
involvement in the rehabilitation process for a period of 1 to 2 months (or
more), particularly in the absence of a viable means of communication, can lead
to feelings of isolation, depression, and frustration.
a) Patients are
usually ready to begin esophageal speech training shortly after they begin
to take food by mouth. The beginning of
oral feeding suggests that wound healing has progressed to the point where
attempts to produce sound will not jeopardize further recovery.
b) Use of an oral type
of electronic speech aid can often begin within days after laryngectomy surgery
assuming the patient’s progress is without complications. The extent of the lesion and of the surgery
must be considered when judging the patient’s readiness for using an electronic
speech aid.
c) Use of a neck-held electronic speech aid can begin as
soon as healing of the surgical suture lines is complete and swelling has
resolved sufficiently to obtain good transcutaneous transmission of sound.
d) In the case of TEF,
readiness for initiation of speech with a prosthesis depends on the healing
of the puncture site.
2) Early use of speech
aid can decrease feelings of isolation, depression, and frustration. In uncomplicated cases, an oral type of
electronic speech aid can be introduced on the fourth to seventh post surgical
day along with instruction in its use.
B. Group Versus
Individual Therapy
Each
approach has its advantages and disadvantages and may be determined by the type
of alaryngeal speech to be pursued, patient preference, clinician style, and
scheduling constraints. The fitting of
prosthesis is best done individually, as is the initial instruction in
producing tracheoesophageal speech. For those patients who will pursue either
esophageal speech training or the use of an electronic speech aid, or both, the
choice of group versus individual therapy can be considered.
1)
Individual
therapy of course, provides the patient with the full and undivided
attention of the speech-language pathologist.
The amount of time given directly to the individual patient is greater
than can be provided to any one
individual in a group setting. Some
patients become anxious and self-conscious in the pressure of a group and may
not learn as fast or as well as when alone.
2)
Group
therapy on the other hand, exposes the individual to others who “are in the
same boat” thus lessening the feelings of isolation. It allows for interchange among group members
about shared concerns other than speech.
Newly laryngectomized persons benefit from the models presented by
others in the group who are further along in the process.
C) Involvement of
Family and / or Friends in Therapy Sessions
Involvement
of significant others is always encouraged.
It is especially important during the initial session, at the very
least, so that family and / or friends can gain a basic understanding of the
rehabilitation process, and specifically speech rehabilitation. Of course, the amount of involvement must
always be tempered by sensitivity to the relationship between the persons
involved. Supportive family members or
close friends can be a major source of help for the patient and can be more
effective when they understand the process.
D) Prognostic Factors
There is no clear way to determine how quickly
or how well functional alaryngeal communication will be acquired. A statement of prognosis is a well educated
guess.
1) The
prognosis for Tracheoesophageal speech
following fistulization in probably most easily and reliably determined. Because the learning time for that type of
speech is very short it is possible to judge relatively quickly how well the
patient will do. However, caution must
be exercised in making the judgment too soon because the healing process may
result in stricture or stenosis that may have a negative effect on speech
production even after an initially positive outcome. If this is suspected, the patient should be
encouraged to see the surgeon.
Furthermore, a small percentage of patients have difficulty in producing
speech following fistulization and may require additional workup and treatment.
2) Prognosis
for the patient who chooses to use an electronic speech aid for purposes of
communication can also be assessed with fairly good accuracy. As a person begins to use the instrument, the
ability to articulate clearly and place the instrument appropriately in quite
obvious.
3) Prognosis
for the acquisition of functional esophageal speech is problematic because it
involves the learning of new skills that are more difficult to acquire than for
either of the other two methods. Factors
such as viability of the pharyngeoesophageal
segment, time elapsed since surgery, age, extent of surgery, hearing
acuity, and personality must be considered.
Even taking all those factors into account, the most skilled and
experienced clinician can still make incorrect judgements. It may be best to err on the side of giving
the patient the benefit of the doubt as long as he or she is motivated and
making the effort to learn.
1)
J
Voice. 2004 Dec;18(4):567-77
Aerodynamic characteristics of laryngectomees breathing quietly and speaking with the electrolarynx.
The primary purpose of this study
was to investigate the aerodynamic characteristics of laryngectomees under two
conditions: breathing quietly and speaking with electrolarynx. Twenty male
adult subjects, 8 normal speakers, and 12 laryngectomees participated the
experiment. Airflow, pressure, and speech data were obtained simultaneously.
The acceptability of electrolarynx speech under different conditions was also
evaluated by 20 listeners (14 men, 6 women). Results indicated a higher peak
expiration airflow and pressure among the laryngectomees as compared with the
normal during breathing. Three different breathing patterns appeared among the
laryngectomees when speaking with the electrolarynx: holding breath, exhaling,
and breathing. Four long-time electrolarynx users held breath during speaking.
Seven of 12 laryngectomees kept exhaling, whereas only 1 could breathe during
speech production. In addition, (1) the acceptability of electrolarynx speech
was the highest when speaking breathlessly; (2) no significant difference was
found in the acceptability between the patterns of exhaling and breathing
smoothly; and (3) the acceptability decreased if breathing quickly during
phonation with the electrolarynx. It also suggests that the laryngectomees who
can breathe during speaking may be more appropriate to use the new
electrolarynx controlling the pitch by expiration pressure.
2) IEEE
Trans Biomed Eng. 2004 Feb;51(2):325-32
Design and implementation of a hands-free electrolarynx device controlled by neck strap muscle electromyographic activity.
The electrolarynx (EL) voice prosthesis is widely used, but
suffers from the inconvenience of requiring manual control. Therefore, a
hands-free EL triggered by neck muscle electromyographic (EMG) activity was
developed (EMG-EL). Signal processing circuitry in a belt-mounted control unit
transforms EMG activity into control signals for initiation and termination of
voicing. These control signals are then fed to an EL held against the neck by
an inconspicuous brace. Performance of the EMG-EL was evaluated by comparison
to normal voice, manual EL voice, and tracheo-esophageal (TE) voice in a series
of reaction time experiments in seven normal subjects and one laryngectomy
patient. The normal subjects produced voice initiation with the EMG-EL that was
as fast as both normal voice and the manual EL. The laryngectomy subject
produced voice initiation that was slower than with the manual EL, but faster
than with TE voice. Voice termination with the EMG-EL was slower than normal
voice for the normal subjects, but not significantly different than with the
manual EL. The laryngectomy subject produced voice termination with the EMG-EL
that was slower than with TE or manual EL. The EMG-EL threshold was set at 10%
of the range of vocal-related EMG activity above baseline. Simulations of
EMG-EL behavior showed that the 10% threshold was not significantly different
from the optimum threshold produced through the process of error minimization.
The EMG-EL voice reaction time appears to be adequate for use in a day-to-day
3) J Voice. 2001
Dec;15(4):592-9
Functional characteristics of a new electrolarynx "Evada" having a force sensing resistor sensor.
Electrolarynxes have been used as
one of the rehabilitation methods for laryngectomees. Earlier electrolarynxes
could not alter frequency and intensity simultaneously during conversation.
Recently, we developed an electrolarynx named "Evada" (prototype so
far) using a force sensing resistor (FSR) sensor that can control both
frequency and intensity simultaneously during conversation. Employing three
types of electrolarynxes (Evada, Servox-inton, Nu-vois), this study was
undertaken to examine the functional characteristics of Evada for the normal
control group and for laryngectomess. Five laryngectomees and five normal
adults were asked to express three sentences (declarative sentence, "You
stay here.", interrogative sentence, "You stay here?", and
imperative sentence, "You! Stay here.") using three types of
electrolarynxes. Frequency and intensity changes between the first and last
vowels in the three sentences were calculated and analyzed statistically by
paired t test. The frequency changes in the interrogative and imperative
sentences were more prominent in Evada than in Servox-inton and Nu-vois. The
intensity changes in the interrogative and imperative sentences were also more
prominent in Evada than in Servox-inton and Nu-vois. Evada controls frequency
and/or intensity by having the subject press the control button(s). Therefore,
Evada appears to be better at producing intonation and contrastive stress than
Nu-vois and Servox-inton.
ALL THE
BEST !!!!!! PLEASE SO THROUGH OTHER
NOTES ALSO
KUNNAMPALLIL GEJO JOHN,BASLP, MASLP