Department of Otolaryngology

Spasmodic Dysphonia

Understanding The Disorder

Spasmodic dysphonia (SD) 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.

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 (Ad-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 SD (Ab-SD)

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 The cause of spasmodic dysphonia is unknown, but there is treatment that can improve symptoms.


What are the symptoms of SD?

Spasms of the vocal folds cause the typical voice changes of SD – a strained strangled voice for Ad-SD, and breathy voice or soundless breaks in Ab-SD. These are represented below.

Type 1 Symptoms:

  • Strained, strangled voice
  • Voice cuts out while speaking
  • Certain sounds are more difficult to say than others
  •  Other perceive the person to be “emotional”
  •  Increased effort in speaking

Type 2 Symptoms:

  • Breathy voice
  • Soundless breaks in voice
  • Voice cuts out while speaking
  • Increased effort in speaking


How is the diagnosis of spasmodic dysphonia made?

There is no specific test to diagnose SD. Diagnosis is based on the patient’s description of the symptoms, the sound of the voice, and the laryngologist’s and speech-language pathologist’s observation of the vocal folds during speech.

1. Patient History

  • Since there is no specific test to diagnose SD, the symptoms and description of the onset of the voice disorder is very important in the diagnosis.

2. Speech-Language Pathology Evaluation.

  • The pattern of voice breaks is very important in the identification of SD and planning treatment. The speech pathologist is trained to listen and evaluate for these different voice and speech patterns.
  • As part of the physical examination, a patient may be asked to repeat certain phrases designed to bring out voice breaks.
  • Acoustic and aerodynamic measurements may also be used to evaluate voice characteristics.

3. Laryngoscopy

  • Visualizing the vocal folds during speech sometimes allows the clinicians to see the spasm behaviors that are characteristic of spasmodic dysphonia.

4. Neurologic Evaluation

  • A patient may be asked about associated neurologic symptoms, such as weakness or tremor, and about the use of certain medicines or drugs that have been associated with movement disorders. These include anti-psychotic medications, neuroleptic medications, and illegal intravenous drugs.
  • Because SD is a central nervous system disorder, the physical exam should include a careful neurologic examination. Some otolaryngologists will ask that a person with suspected SD see a neurologist for this exam.


Mainstay of Treatment

Botulinum toxin injections into muscles of the voice box can alleviate symptoms – although relief is temporary. Treatments are usually repeated approximately every three to five months.

Voice Therapy

There is, at best, a very limited role for voice therapy in the treatment of spasmodic dysphonia.