VOCAL FOLD PARALYSIS

2 Types:

1. Bilateral paralysis - neither vocal fold will be capable of moving to the midline, making
    phonation impossible
2. Unilateral paralysis - the affected vocal fold will not be able to move to midline, causing a
    weak and breathy voice.

Description and Etiology:

* Lesions that affect the vagus nerve may result in paresis or paralysis of muscles in the larynx.
* Other causes include: neuritis; neoplasms in neck, bronchi, and chest; acute external trauma to
    neck; surgery; idiopathic causes; birth trauma; and central nervous system disease
* Lesions may affect the abductory function of the vocal folds, which opens the airway for
    inspiration.

Perceptual Voice Signs and Symptoms:

* Most common symptoms of unilateral paralysis are breathiness and hoarseness
* Diplophonia may occasionally be present in unilateral paralysis
* Severe breathiness or aphonia will be the result of bilateral paralysis of the adductor type
* Voice will be near-normal in the abductor type, but may occasionally present with inspiratory
    stridor.

Acoustical Signs:

* Increased jitter and shimmer
* Reduced pitch range
* Reduced variability of pitch
* Higher noise levels
* Reduced vocal intensity range

Measurable Physiological Signs:

* Higher mean airflow rates occur in unilateral paralysis than in bilateral paralysis

Observable Physiological Signs:

* Stroboscopic signs include: abnormal vibration; large irregular amplitudes; poor vocal fold
    closure; asymmetrical vibration; affected fold seems to flutter; and absence of edge deflections

Pathophysiology:

* A paralyzed vocal fold may affect adduction or abduction of the vocal folds.

Kim Reusch, 1997