Download pl1 intro to larynx - Michigan State University

Peter R. LaPine, Ph.D.
Department of Audiology
and
Speech Sciences
Michigan State University
The “Plan”
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Voice disorder: Any deviation in pitch, intensity, quality, or other basic
vocal attribute which consistently interferes with communication, draws
unfavorable attention, adversely affects the speaker or the listener, or is
inappropriate to the age, gender, or perhaps the culture or class of the
individual, may be organic or functional in nature and may be the result of
laryngeal function or resonance disorders.
Hyperfunction: Excessive forcing and straining, usually at the level of the
vocal folds, but which may occur at various points along the vocal tract.
Hypofunction: Reduced vocal capacity resulting from prolonged overuse,
muscle fatigue, tissue irritation, or general laryngeal or specific problems
relating to the opening and closing of the glottis characterized by air loss
and sometimes hoarseness and pitch breaks.
Aphonia: Complete loss of voice as a result of hysteria (conversion),
growths, paralysis, disease, or overuse of the vocal folds which may develop
suddenly or over a period of time; in a less severe form, often referred to as
dysphonia.
Common Terms
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Voice Disorder
Hyperfunction
Hypofunction
Aphonia
Dysphonia
Laryngeal Pathology
Vocal Pathology :{ )
Speech Dynamics
• Speech on exhalation
from lungs
• Activates the vocal
folds
• Voiced sound
(phonation) passes
through the pharynx
and oral cavity
• Articulators modulate
Prosection of the Larynx
• 9 cartilages; 1 bone
• 5 intrinsic laryngeal
muscles to regulate
mass, length and
tension of the vocal
fold
• It is a VALVE; it’s
binary
• TVF = true vocal fold
• FVF = false vocal fold
• Trachea = “windpipe”
Coronal Section of the Larynx
• TVF and FVF
• TVF shape and
histology
Valve Functions of the Larynx
• Abduct: Posterior
cricoarytenoid m.
• Adduct: Lateral
Cricoarytenoid m.
(and the Transverse
and Oblique Arytenoid
muscles.
• “Open” at rest
Vocal Fold Activity
• Closed-Open-Closed
• Medial Compression
• Vocal “cord”, ligament
and fold
• Frequency, Amplitude
and Waveform
• Perturbation values:
jitter and shimmer
• 1 cycle of vocal fold
vibration
• “closed-open-closed”
• Aerodynamic process
• Myoelastic process
• Frequency perceived
as “pitch”
Vocal Fold Movement
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Closed-Open-Closed
Stroboscopic view
Medial compression
Male Frequency
Range: 118-150 Hz
• Female Frequency
Range: 180-240 Hz
Speech is a MOTOR act
• Nerves activate and
fire
• Muscles are “moved”
by the nerve impulse
• Cranial nerves that
control speech:
Trigeminal, Facial,
Hypoglossal, Vagus,
and Accessory
Recurrent Laryngeal Nerve
• Asymmetrical branch
of CX
• “Feeds” the intrinsic
laryngeal muscles
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PCA
LCA
OA/TA
TA
SUBJECTIVE
CHARACTERISTIC
OBJECTIVE
MEASURE (UNIT)
PITCH
FREQUENCY (Hz/CPS)
JITTER
LOUDNESS
INTENSITY (dB SPL)
SHIMMER
QUALITY
WAVEFORM
SIGNAL:NOISE
HARMONIC RATIO
Nerve Damage
• CX: The Vagus
• Recurrent Laryngeal
Nerve
• Image of unilateral
cord paralysis
• Dec’d pitch
• Respiration for speech
is inefficient
Medications
• Coordination and proprioception
(stimulants, sedatives,nervousness, tremors,
pain masking)
• Airflow (bronchodilators, constrictors,
nervousness, tremor)
• Fluid balance (decongestants,---”rebound
effect”--edema, sedating, decreased energy
Medications, cont.
• URT secretions--(antihistamines, dryness,
sedation)
• Hormonal (androgens, increasing vocal
mass)
• Gastrointestinal Reflux Disorder: GERD--OTC medications, diet.
Laryngeal Pathology
• An ANATOMICAL CHANGE in the size,
structure or shape of the larynx
• A pathology is a deviation in the normal
structure caused by disease or other
systemic variation
Benign Lesions
• Vocal Nodules
• Vocal Polyps:
Sessile
Peducunlated
• Contact Ulcers
• Granuloma
• Papilloma
Added Mass
• Top view: vocal
nodules (bilateral)
• Bottom view: vocal
polyp (sessile)
Swelling
• Reinke’s Edema
• Increased mass,
decreased pitch
(frequency)
• Atypical perturbation
values
Plicae Ventricularis
• False vocal fold
vibration
• Decreased pitch and
decreased frequency
(< 90 Hz)
• Limited Pitch e.g.,
“Monopitch”
“Bowed Vocal Cords”
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Chronic Laryngitis
Presbylaryngis
Fatigue/Overuse
Symptoms:
– decreased intensity
– decreased respiratory
control
– decreased pitch range
Granuloma
• Associated with
physical irritation;
abrasion of the
mucous cover of the
vocal fold
• Adds mass: decreases
pitch (frequency),
increases perturbation
values
Intracordal cyst
• Note left side of body
(slide right!)
• Added mass
• Incomplete medial
compression of true
vocal fold
• Result: increased mass
and air escape