Spasmodic Dysphonia (SD) is a disorder of speech which results in inappropriate laryngeal (voice box) muscle contractions. It may present as a strained and strangled voice, a breathy and whispering voice or rarely as noisy breathing. It was originally described in 1871 and for nearly a century was thought to be a psychosomatic illness. However, today we know that it is a neurological abnormality (illness of the nervous system) although the exact cause is still to be identified.
Spasmodic Dysphonia (SD) may affect the muscles that close the larynx (voice box) causing a strained and strangled voice. This is called adductor SD. Or it may affect the muscles that open the larynx called abductor SD. This gives a breathy, whispering quality to the voice. A few patients may have a mixture of both. Most cases involve only the larynx (70%) but occasionally the voice problem will be associated with movement disorders (dystonia) of another part of the body. Women are afflicted slightly more often than men (63%) and there is some evidence that the condition may be inherited. In one study 12% of patients had another family member with similar symptoms. A small percent of patients may have dystonias which eventually spread to other parts of the body.
Your physician or PA will take a detailed history of your difficulties and past medical history. They will want to know when you first noticed the problem, if it came on suddenly after an illness or stressful event and when it bothers you the most. You will be asked if there is any activity or time when the symptoms are worse (ie, talking on the telephone) or better (ie. while singing, laughing or after an alcoholic drink). You will also be asked if there are certain words that are more difficult to say than others. People with adductor type SD will have difficulty with voiced vowel sounds as in the sentence, “We mow the lawn all year.” or when counting from 80 to 90. Those with abductor SD will have problems with voiceless consonant sounds (f, p, s) and will have difficulty with sentences like, “Harry had a hard hat.”, or The puppy bit the tape.”
Breathing dystonia is a rare form of adductor SD and occurs only on inspiration (when the patient is breathing in). The patient will have a normal voice, cough and swallow but will make noise when breathing. This rarely causes the patient discomfort and disappears when they are sleeping.
After taking a detailed history and examining you, the physician or PA will perform a fiberoptic endoscopic examination of your larynx. First the tissues of the nose and throat will be numbed with local anesthetic. Then a tiny camera on a flexible tube (endoscope) will be placed into the nose and down the back of the mouth. While the examiner is looking through the endoscope you will be asked to say some sentences and make certain sounds. The camera will record the motion of the larynx during these exercises. With adductor SD there will be an over closure or squeezing of the vocal cords which can be seen through the endoscope. In patients with abductor SD, the vocal cords are not able to close completely after the voicing of certain sounds.
Because this is a neurologic condition which may present as a symptom of other illnesses such as MS, Parkinson’s Disease or Meige Disease, it is strongly recommended that the patient be evaluated by a neurologist as well as an ENT doctor. This additional evaluation will identify any other affected body parts and rule out causative disorders prior to treatment.
Botulinum toxin (Botox) injection guided by electromyography (EMG) is the gold standard of treatment for uncomplicated SD. The physician will target the appropriate muscle in the larynx using the guidance of an electrode needle and EMG machine. This machine picks up the electrical signal that is produced by the muscle spasm. A dose of Botox is injected into the muscle after it is identified by EMG. This toxin will cause a partial, temporary weakness of the muscles of the larynx. Depending on the outcome of the endoscopic exam the physician may choose to inject both or just one side of the larynx. Most patients get 1 to 3 months of significant improvement without suffering uncomfortable side effects.
Since no two patients are identical, the starting dose is uncertain and may not provide the desired result. If this is the case the patient will be asked to return in two weeks for reevaluation. A booster injection can be given if desired. If the resultant effect creates unwanted side effects such as choking on liquids, breathiness of voice, or total loss of voice, the patient will be asked to wait until the effect wears off and return for evaluation. Subsequent injections will be given at a reduced dose. It may take several injections to determine the optimal dose for you. It is important to understand that the effect of Botox is temporary and side effects can be dealt with by using a few simple techniques like sipping through a straw, chin tuck when swallowing and coughing after each swallow.
Medications have been used as primary treatment. However, they have not been shown to have significant effect on true SD. They can be used to boost and prolong the effect of Botox injections. Likewise, voice therapy alone has been shown to be of little benefit when treating SD. However, the skill of a therapist trained in voice disorders is essential in the diagnosis of SD and can prolong the result of injections with prevention of poor vocal hygiene and breath support strategies.
Several surgical procedures which either weaken the muscles of the larynx or alter the function of the main nerve controlling the larynx have been proposed. Although many give excellent results initially, over time spasms have returned and the benefit decreases. A promising procedure is called Selective Laryngeal Denervation-Renervation (SLD/R) and involves cutting the recurrent laryngeal nerve and reattaching it to a cervical nerve branch in the neck. All patients can expect to experience 3 to 6 months of breathiness and approximately 10% of patients have swallowing difficulty.
Deep Brain Stimulators (DBS) has been used for generalized dystonia but has not had predictable effects on laryngeal dystonia.
For many decades this disorder of the voice was considered to be psychogenic and a result of anxiety or depression. Today we understand that the depression felt by many patients is secondary to the disability created by SD. As with any form of depression, regardless of its cause, it is important to seek the counsel of your primary care physician. Treatment for depression and avoidance of stressful life styles can augment treatment of SD. Support from family, friends and employers is helpful.
Many patients also benefit from communicating with others coping with SD. For more information on support groups, we recommend contacting the National Spasmodic Dysphonia Association at One East Wacker Drive, Suite 2430, Chicago, IL 60601-1905, Phone: 1-800-795-6732, Email: NSDA@dysphonia.org, Website: www.dysphonia.org.