At 87, Elizabeth Longlife comes in with her children. The children complain that Elizabeth is getting more difficult to understand over the past five years. She sounds unsteady to them. Ms. Longlife states that she is not bothered by her voice but came in at the request of her children.
Unlike the irregular spasm of adductor spasmodic dysphonia, a vocal tremor is a regular oscillation of the larynx giving the voice a very shaky or unsteady sound. Frequently, a vocal tremor does not bother the person who has it. Mostly it bothers those who have to listen to and understand the person with the vocal tremor. Generally, a patient with spasms senses a great deal of effort and feels they are fighting against the spasms. A patient with tremor does not sense any significant increase in effort with making sound. Her voice is just unsteady.
Vocal tremor can be mitigated to some degree with medications that work for other types of tremor. The most common medication is propranolol, which will tend to decrease the intensity of the oscillations but not eliminate them. Mrs. Longlife was happy to know that she didn’t need any more medications unless the tremor was to the point that it bothered her.
Frequently, a vocal tremor does not bother the person who has it. Mostly it bothers those who have to listen.
Neurologic Combinations
It is not uncommon to have more than one of the above types of tremor or spasms. About 10 percent of people with adductor spasmodic dysphonia also have a vocal tremor. A person may have both adductor and abductor spasmodic dysphonia. A patient may have a vocal cord dystonia and a neck dystonia. In a person with a mixed neurologic voice disorder, I typically begin treatment for one of the disorders at a time so that both the patient and I may decide how effective each treatment is alone before combining them.
What you learned
- A vocal tremor is a rhythmic, regular oscillation of the larynx — distinguishable from dystonic spasms by its regularity (approximately 4 oscillations per second) and the patient’s lack of perceived effort.
- Tremor typically bothers listeners more than the patient; many patients are unaware of how shaky their voice sounds to others.
- Propranolol reduces the intensity of vocal tremor but does not eliminate it; treatment is warranted only when the tremor significantly affects communication or quality of life.
- Neurologic voice disorders often co-occur — about 10% of patients with adductor spasmodic dysphonia also have a vocal tremor — and mixed cases require treating one disorder at a time to assess each treatment’s contribution.