The Voice Foundation

How Breakdowns Result in Voice Disorders

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How Breakdowns Result in Voice Disorders

Key Glossary Terms

Larynx
Highly specialized structure atop the windpipe responsible for sound production, air passage during breathing and protecting the airway during swallowing

Vocal Folds (also called Vocal Cords)
"Fold-like" soft tissue that is the main vibratory component of the voice box; comprised of a cover (epithelium and superficial lamina propria), vocal ligament (intermediate and deep laminae propria), and body (thyroarytenoid muscle)

Glottis (also called Rima Glottides)
Opening between the two vocal folds; the glottis opens during breathing and closes during swallowing and sound production

Glossary

In Brief

Voice disorders refer to breakdowns in the vibratory system. Breakdowns can affect any one or all of the three subsystems of voice production.

Air Pressure System

If the airflow source is weak or inefficient (making it difficult to push enough air out of lungs), the voice will be weak and hampered by shortness of breath.

For example: Patients with asthma, lung cancer, emphysema and other lung conditions often find it difficult to speak loud or for long periods of time.

Vibratory System

Any compromise or change to vocal fold vibration causes hoarseness and other voice symptoms.

For example: Patients with stiffness in the vocal folds from swelling from a common cold develop hoarseness.
For example: When focal folds cannot come perfectly together from partial nerve input loss, air leak occurs and the voice is "breathy."

Resonating System or Vocal Tract

A breakdown of the vocal tract can affect voice quality.

For example: When nasal passageways are swollen and inflamed during the "common cold," the voice takes on a nasal quality.

Making Sense of It All

The following are a few examples depicting how breakdowns result in voice disorders and a few of the many possible voice symptoms.

Correlating Anatomy, Voice Function, Abnormalities, and Possible Voice Disorder Symptoms

Sound Process

Brief Description

A Glimpse – "who does what" in Sound Production

Examples of "Breakdowns" that Affect Sound Process

Possible Symptoms

Generating Air Pressure

"Breath Support"
Coordinated functions of diaphragm, abdominal and chest muscles, lungs and chest cavity move air column upwards through vocal folds

Diaphragm, abdominal and chest muscles move air into and out of lungs

Lungs are the organs for air

Bronchi and trachea are the passageway for air from lungs

Lung disease

Airway obstruction: asthma, subglottic stenosis

Paresis/paralysis of muscles

Shortness of breath

Weak voice

Glottic Closure

Position of vocal folds

Vocal Fold Position Critical
Vocal folds are in closed position for speech or singing
[Note: Vocal folds are open for breathing]

Laryngeal muscles contract to close vocal folds

Arytenoid cartilages pivot to move vocal folds towards midline ["closed"]

RLN and SLN bring nerve inputs to muscles

Vocal fold mass and edge contribute to glottic closure

Paresis/paralysis – RLN/SLN

Muscle weakness

Neurological diseases; muscular disorders

Arytenoid arthritis

Vocal fold granuloma

Vocal fold nodules, polyps, cysts

Vocal fold atrophy

Vocal fold scarring

Hoarseness

Breathiness

Effortful phonation

Vocal fatigue

Diplophonia

Vocal Fold Vibration Produces Voiced Sound

Wavelike Vibration from Bottom to Top–repeat vibratory cycles

With each vocal fold vibratory cycle, a puff of air escapes, producing voice sound ("buzzy sound")

Singing voice produces unique sound spectra (singing formants) that are distinct from spoken voice

Superficial lamina propria is the main vibrating layer in vocal fold mucosa

Vocal fold pliability is critical for vibration

Vocal fold surface integrity allows mucosal wave propagation

Vocal fold mass and edge contribute to glottic closure

Vocal fold scar

Vocal fold lesions: cysts, nodules, polyps, papilloma

Vocal fold granuloma

Swelling and inflammation (reflux laryngitis, viral laryngitis)

Reinke's edema

Paresis/paralysis

Hemorrhage, vascular ectasias

Hoarseness

Effortful phonation

Weak voice

Speaking voice lower than usual

"Vocal fry"

Voice fatigue

Voice Volume or Loudness

Amplitude of Sound Waves
Loudness is achieved by:

Increasing air pressure/flow

Increasing vocal fold resistance

Breath support

Laryngeal muscles contract to adjust tension of vocal folds

Vocal fold elasticity allows folds to "open wider" and "stay apart" longer

Vocal fold scar

Paresis/paralysis

Vocal fold lesions: cysts, nodules, polyps, papilloma

Vocal fold granuloma

Swelling and inflammation (reflux laryngitis, viral laryngitis)

Unable to project voice

Weak voice

Voice breaks

Voice Pitch or Highness / Lowness

Frequency of Sound Waves

Increased tension for high notes (high frequency)

Decreased tension for low notes (low frequency)

Greater air pressure and increased tension for high notes

Laryngeal muscles contract to adjust tension of vocal folds–especially for high notes

Vocal fold elasticity/pliability

Vocal fold edge integrity

SLN paresis/paralysis

Vocal fold scar

Reinke's edema

Vocal fold lesions

Unable to hit high notes

Loss of glissando

Voice breaks

Voice Quality or Timbre

Person's "Own" Voice
Vocal tract resonators amplify and modify voiced sound, giving personal quality to a person's voice

e.g., John's voice not equal to Jim's voice

Vocal fold elasticity/pliability

Vocal fold resistance

Vocal fold mass

Person's vocal fold features: e.g., stiffness, bulk, size

Vocal tract resonators (throat, oral cavity, nasal cavities)

Learning About the Voice Mechanism