Spasmodic Dysphonia (SD)
A voice disorder resulting from involuntary movements (spasms) of the voice box muscles.
A nervous system problem that causes involuntary movement; dystonia is not a psychological problem; SD is a type of dystonia
Adductor SD (Ad-SD)
Spasms in muscles that close vocal folds, which interrupt speech and cause strained or strangled voice breaks
Abductor SD (Ab-SD)
Spasms in muscles that open vocal folds, which interrupt speech and cause breathy or soundless voice breaks
Spasmodic dysphonia is a voice disorder resulting from involuntary movements (or spasms) of the voice box muscles. These spasms interrupt normal voice (dysphonia) in “abrupt spurts” with a strained, strangled voice, with breathy, soundless voice, or with a mixture of both.
- Spasmodic: spasms or involuntary movements
- Dysphonia: abnormal voice
A Neurological Disease
SD is a type of dystonia, a disorder of the central nervous system that causes involuntary movement of the vocal folds during voice production.
SD is not a psychiatric or psychological disease.
Swallowing and breathing, the other important functions of the voice box, are almost never affected.
Three Types of Spasmodic Dysphonia
Type 1: Adductor SD (80% to 95% of cases)
What Happens: Vocal folds come together (close) tightly at the wrong time during speech, making it difficult to produce voice
How the Voice Sounds: Strained, strangled breaks while speaking
Type 2: Abductor SDM
What Happens: Vocal folds move apart (open) at the wrong time during speech, causing air leaks
How the Voice Sounds: Breathy or soundless breaks while speaking
Type 3: Mixed SD
What Happens: Combination of abductor and adductor SD
How the Voice Sounds: Sometimes strained, strangled breaks; sometimes breathy or soundless breaks
Unknown Cause, but Treatment Can Improve Voice Problem
For spasmodic dysphonia, like all dystonias:
- The cause is unknown
- There is no specific test for diagnosis
- There is no known cure–but treatment can and does improve symptoms
Mainstay of Treatment
Botulinum toxin injections into muscles of the voice box can alleviate symptoms – although relief is only temporary. Treatments are usually repeated approximately every three months.
Outlook on Treatment
In almost every case of spasmodic dysphonia, symptoms can be improved with treatment.
Patient education material presented here does not substitute for medical consultation or examination, nor is this material intended to provide advice on the medical treatment appropriate to any specific circumstances.
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