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What Is
Vocal
Fold
(cord)
Paresis
And
Paralysis?
Vocal
fold (or
cord)
paresis
and
paralysis
result
from
abnormal
nerve
input to
the
voice
box
muscles
(laryngeal
muscles).
Paralysis
is the
total
interruption
of nerve
impulse
resulting
in no
movement
of the
muscle;
Paresis
is the
partial
interruption
of nerve
impulse
resulting
in weak
or
abnormal
motion
of
laryngeal
muscle(s).
Vocal
fold
paresis/paralysis
can
happen
at any
age –
from
birth to
advanced
age, in
males
and
females
alike,
from a
variety
of
causes.
The
effect
on
patients
may vary
greatly
depending
on the
patient’s
use of
his or
her
voice: A
mild
vocal
fold
paresis
can be
the end
to a
singer's
career,
but have
only a
marginal
effect
on a
computer
programmer's
career.
What
Nerves Are
Involved
In Vocal
Fold
Paresis/Paralysis?
Vocal fold
movements
are a
result of
the
coordinated
contraction
of various
muscles.
These
muscles
are
controlled
by the
brain
through a
specific
set of
nerves.
The nerves
that
receive
these
signals
are the:
Superior
laryngeal
nerve
(SLN),
which
carries
signals to
the
cricothyroid
muscle,
located
between
the
cricoid
and
thyroid
cartilages.
Since the
cricothyroid
muscle
adjusts
the
tension of
the vocal
fold for
high notes
during
singing,
SLN
paresis
and
paralysis
result in
abnormalities
in voice
pitch and
the
inability
to sing
with
smooth
change to
each
higher
note.
Sometimes,
patients
with SLN
paresis/paralysis
may have a
normal
speaking
voice but
an
abnormal
singing
voice.
The
recurrent
laryngeal
nerve
(RLN)
carries
signals to
different
voice box
muscles
responsible
for
opening
vocal
folds (as
in
breathing,
coughing),
closing
vocal
folds for
vocal fold
vibration
during
voice use,
and
closing
vocal
folds
during
swallowing.
The
recurrent
laryngeal
nerve goes
into the
chest
cavity and
curves
back into
the neck
until it
reaches
the
larynx.
Because
the nerve
is
relatively
long and
takes a
"detour"
to the
voice box,
it is at
greater
risk for
injury
from quite
different
causes –
such as
infections
and tumors
of the
brain,
neck,
chest, or
voice box;
as well as
complications
during
surgical
procedures
in the
head,
neck, or
chest
regions –
that
directly
injure,
stretch,
or
compress
the nerve.
Consequently,
the
recurrent
laryngeal
nerve is
involved
in
majority
of cases
of vocal
fold
paresis or
paralysis.
What Are
The Causes
Of Vocal
Fold
Paralysis/Paresis?
The cause
of vocal
fold
paralysis
or paresis
can
indicate
whether
the
disorder
will
resolve
over time
or whether
it is most
likely
permanent.
When a
reversible
cause is
present,
surgical
treatment
will most
likely not
be
recommended
given the
likelihood
of
spontaneous
resolution
of the
paresis or
paralysis.
Despite
advances
in
diagnostic
technology,
physicians
are unable
to detect
the cause
in about
half of
all vocal
fold
paralyses.
These
cases are
referred
to as
idiopathic
(due to
unknown
origins).
In
idiopathic
cases,
paralysis
or paresis
might be
due to a
viral
infection
affecting
the voice
box nerves
(RLN or
SLN) or
the vagus
nerve, but
this
cannot be
proven in
most
cases.
Known
reasons
for injury
can
include:
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Inadvertent
injury
during
surgery:
Surgery
in the
neck
(e.g.,
surgery
of
thyroid
gland,
carotid
artery)
or
surgery
in the
chest
(e.g.,
surgery
of the
lung,
esophagus,
heart,
or
large
blood
vessels)
may
inadvertently
result
in RLN
paresis
or
paralysis.
The
SLN
may
also
be
injured
during
head
and
neck
surgery. |
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Complication
from
endotracheal
intubation:
Injury
to the
RLN
may
occur
when
breathing
tubes
are
used
for
general
anesthesia
and/or
assisted
breathing
(artificial
ventilation).
However,
this
type
of
injury
is
rare,
given
the
large
number
of
operations
done
under
general
anesthesia. |
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Blunt
neck
or
chest
trauma:
Any
type
of
penetrating,
hard
impact
on the
neck
or
chest
region
may
injure
the
RLN;
impact
to the
neck
may
injure
the
SLN. |
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Tumors
of the
skull
base,
neck,
and
chest:
Tumors
(both
cancerous
and
non-cancerous)
can
grow
around
nerves
and
squeeze
them,
resulting
in
varying
degrees
of
paresis
or
paralysis. |
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Viral
infections:
Inflammation
from
viral
infections
may
directly
involve
and
injure
the
vagus
nerve
or its
nerve
branches
to the
voice
box
(RLN
and
SLN).
Systemic
illnesses
affecting
nerves
in the
body
may
also
affect
the
nerves
to the
voice
box. |
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What Are
The
Symptoms
Of Vocal
Fold
Paralysis/Paresis?
Both
paresis
and
paralysis
of voice
box
muscles
result in
voice
changes
and may
also
result in
airway
problems
and
swallowing
difficulties.
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Voice
changes:
Hoarseness
(croaky
or
rough
voice);
breathy
voice
(a lot
of air
with
the
voice);
effortful
phonation
(extra
effort
on
speaking);
air
wasting
(excessive
air
pressure
required
to
produce
usual
conversational
voice);
and
diplophonia
(voice
sounds
like a
"gargle").
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Airway
problems:
Shortness
of
breath
with
exertion,
noisy
breathing
(stridor),
and
ineffective
or
poor
cough.
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Swallowing
problems:
Choking
or
coughing
when
swallowing
food,
drink,
or
even
saliva,
and
food
sticking
in
throat. |
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How Is
Vocal Fold
Paralysis/Paresis
Diagnosed?
The
otolaryngologist—head
and neck
surgeon
will
conduct a
general
examination
and then
question
you
regarding
your
symptoms
and
lifestyle
(voice
use,
alcohol/tobacco
consumption).
The
examination
of the
voice box
will be
undertaken
to
determine
whether
one or
both vocal
folds
(cords)
is/are
abnormal.
Determining
whether
one or
both vocal
folds are
affected
is
important
in the
treatment
plan.
Other
tests may
be
required:
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Laryngeal
electromyography
(LEMG):
LEMG
measures
electrical
currents
in the
voice
box
muscles
that
are
the
result
of
nerve
inputs.
Measuring
and
looking
at the
pattern
of the
electric
currents
will
indicate
whether
there
is
recovery
or
repair
of
nerve
inputs
(re-innervation)
and
the
degree
of the
nerve
input
problem.
The
test
involves
the
insertion
of
small
needles
that
can
measure
electrical
currents
in the
vocal
fold
muscles.
During
LEMG
patients
perform
a
number
of
tasks
that
would
normally
elicit
characteristic
actions
in the
tested
muscles.
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Other
tests:
Because
there
is a
wide
list
of
diseases
that
may
cause
a
nerve
to be
injured,
further
testing
is
usually
necessary
(blood
tests,
x-rays,
CT
scans,
MRI,
etc.)
to
identify
the
cause(s)
of
vocal
fold
paresis/paralysis. |
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What Is
The
Treatment
For Vocal
Fold
Paralysis/Paresis?
The two
treatment
strategies
to improve
vocal
function
are voice
therapy,
the
equivalent
of
physical
therapy
for large
muscle
paresis/paralysis;
and
phonosurgery,
an
operation
that
repositions
and/or
reshapes
the vocal
fold(s) to
improve
voice
function.
Normally,
voice
therapy is
a first
treatment
option.
After
voice
therapy,
the
decision
for
surgery is
dependent
on the
severity
of the
symptoms,
vocal
needs of
the
patient,
position
of
paralyzed
vocal
folds,
prognosis
for
recovery,
and cause
of
paresis/paralysis
if known.
If you
have
notice any
change in
voice
quality,
immediately
contact an
otolaryngologist—head
and neck
surgeon.
Material provided courtesy of the
American Academy of Otolaryngology — Head and Neck Surgery
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