In the United States, about 30 percent of people have a voice disorder in which the patient has difficulty with vocal quality, duration, resonance, loudness or pitch, according to the American Speech-Language-Hearing Association. One type of voice disorder is vocal cord paralysis, in which the layrnx’s nerve pulses are interrupted.
There are two types of vocal cord paralysis: unilateral vocal cord paralysis and bilateral vocal cord paralysis. With unilateral vocal cord paralysis, one of the two vocal cords in the larynx becomes paralyzed or has limited movement. With bilateral vocal cord paralysis, both of the vocal cords are paralyzed. The MayoClinic.com noted that unilateral vocal cord paralysis is more common than bilateral vocal cord paralysis.
Different types of injuries to the vocal cords can result in vocal cord paralysis. For example, a neck or chest injury may cause vocal cord paralysis. Surgery around the neck or upper chest can paralyze the vocal cords. Tumors, stroke and inflammation of the vocal cord are other causes.
Congenital defects of the larynx can also cause vocal cord paralysis. Between 10 and 15 percent of all congenital laryngeal disorders are this type of paralysis, according to the Children’s Hospital of Philadelphia.
Patients with unilateral vocal cord paralysis can have noisy breathing, aspiration and a weak cry. With bilateral paralysis, patients experience a shortness of breath during activities, blue spells, aspiration and noisy breathing. Other symptoms include hoarseness, limited pitch and an inability to speak loudly. The American Speech-Language-Hearing Association stated that aspiration of food and liquids into the lung may lead to pneumonia.
The Children’s Hospital of Philadelphia noted that in many cases of unilateral vocal cord paralysis, immediate treatment is not needed. Treatment for a weak voice from unilateral vocal cord paralysis may include injecting filler into the paralyzed vocal cord or restoring nerve functioning.