Voice disorders include impaired ability to produce voice (dysphonia) and inability to produce voice (aphonia). Normal voice is produced by the vibration of the vocal folds (vocal cords), two small muscles in the larynx (voice box). Anything that disrupts the vibration of these vocal folds will cause changes in voice quality.
One cause of voice disorders is unilateral (one-sided) or bilateral (two-sided) weakness or paralysis of the vocal cords due to nerve damage from neurological diseases, injuries, or other causes. Growths on the vocal cords (nodules or polyps) that interfere with their complete closure can cause a hoarse and breathy sounding voice. These growths are often caused by vocal abuse such as excessive loud talking, singing, yelling, or crying; frequent coughing or throat clearing; or tense throat/neck muscles during speaking or singing. Smoking, heavy intake of caffeine or alcohol, acid reflux, and allergies can also contribute to these growths. Spasmodic dysphonia is a chronic type of voice disorder that causes a harsh, strained sounding voice due to tremors or abnormal muscle tone in the vocal cords. Voice disorders also frequently occur with Parkinson's disease.
Symptoms of Voice Disorders
Symptoms may range from mild to severe. If they are severe enough, they may make speech hard to hear or understand. They include:
- Hoarse, scratchy, breathy, strained or strangled sounding voice
- Discomfort when using the voice
- Overly high or low pitch
- Restricted range of pitch and/or loudness
- Voice that quickly fatigues
Assessing and Treating Voice Disorders
The Speech-Language Pathologist (SLP) will first take a thorough medical history, including questions about voice habits and other social habits such as smoking, drinking alcohol, etc. She will have the client complete various speech tasks to assess voice quality, pitch, loudness, and duration. A scope (thin tube with a camera) may be inserted through the nose to look at the larynx and the movement of the vocal folds. The SLP may use specialized instruments to measure the acoustic features of the voice. Exams by an ear, nose and throat doctor (ENT) and sometimes a neurologist are often necessary in addition to the voice evaluation by the SLP.
Treatments for voice disorders will depend upon the diagnosis. The SLP may train the client in vocal hygiene techniques – ways to avoid vocal abuse and promote good health of the larynx and vocal folds. The client may do exercises to strengthen the movements of the vocal folds, increase breath support, or promote relaxation of tense throat and larynx muscles. Special instruments and computer programs can be used to provide visual feedback about a client's voice output, so she can learn to make adjustments. A therapy program called Lee Silverman Voice Therapy (LSVT®) that focuses on louder and clearer voice production may be provided for clients with Parkinson's or other neurological voice problems.
Sometimes medical treatments are necessary. These may include: injections to relax the vocal folds for spasmodic dysphonia; medications to treat allergies, reflux or thyroid problems; or surgeries to remove growths, or to move or enlarge a paralyzed vocal cord.