Background
Dysphonia (voice disorder) is relatively common in the general population, occurring in about a third of all people at some point in their lifetime but occurs in only about 2% of persons with MG. On the other hand, dysarthria (slurred speech) is less common in the general population, but occurs in over 10% of people with myasthenia gravis. Difficulty voicing or speaking can affect job performance and may cause a person to feel socially isolated because they have a hard time being heard or understood.
Human voice production starts by generating air pressure in the lungs. It flows through the vocal folds (vocal cords), causing them to vibrate and produce sound. Symmetric and fluid vibration of the vocal folds creates a pleasing, smooth voice. Human speech is produced by using the muscles of the throat, jaw, palate, tongue, and lips to shape the sound generated by the voice box into consonants and vowels. When the muscles of the lungs, vocal tract, throat or mouth are affected in MG, we may see symptoms of voice, speech, and swallowing problems.
Voice problems seen in MG include vocal fatigue (voice wears out over the day or with prolonged speaking tasks), difficulty controlling pitch, or a monotone voice (lack of ability to change vocal pitch). The voice problem can stem from poor breath support or from weakness causing the vocal folds not to move properly. Speech disturbances include a hypernasal voice or slurred speech (dysarthria). Dysarthria is more frequently seen in younger patients diagnosed with MG, whereas dysphonia is more often seen in elderly men with MG. Typically, the symptoms appear and/or worsen with continuing or extended speech.
Diagnosis
The diagnosis of dysphonia or dysarthria is often very apparent to a person with MG because they perceive a change in their voice or speech production. Sometimes, the symptoms may be subtle or intermittent. A speech-language pathologist or a medical doctor makes the diagnosis. Since dysarthria is a common symptom of stroke, any new onset of dysarthria should be immediately evaluated by a medical professional. Any person with vocal disturbance lasting more than 2 weeks should seek medical attention in a timely manner.
If you are experiencing a voice disorder, you may be referred to an ear, nose, and throat (ENT) physician to be sure that the dysphonia is due to MG and not another cause. The ENT physician will usually perform a laryngoscopy. This is a relatively straightforward examination that uses a small flexible camera inserted through the nose to visualize the upper airway. It is done with local anesthesia in the office setting and only takes a few minutes to complete.
Treatment
The treatment of speech and voice disorders in MG is individualized and based on the underlying cause and severity of the problem. Pharmacological therapies used for other symptoms of MG are typically utilized. Other treatments may involve therapy with a speech-language pathologist. Strengthening exercises and/or compensatory strategies may be employed to help increase understandability. A strengthening program is not indicated during a myasthenic crisis or exacerbation, but may be implemented during stability or when in remission. Exercises should be performed during peak drug therapy. Always review any plan of care with your MG treating provider.
Improvement and prognosis of voice and speech is often related to the treatment of overall MG disease. Research will continue to play an important role in answering questions and developing new treatments.
| Documents to download |
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| MGFA-brochure-Effects-of-MG-on-Voice-and-Speech.pdf (985.03 KB) |