Vocal tremor may occur alone or in combination with other neurologic conditions, particularly laryngeal dystonia. About 10% of my patients with laryngeal dystonia or spasmodic dysphonia also have vocal tremor.
A general sense that I have about vocal tremor is that typically patients are not bothered by their unsteady voice. More commonly it is someone they know, friend or family, who inquires about their unsteady voice. Typically, speaking is not effortful. This is in contrast to laryngeal dystonias, where quite often, the patient senses a great effort to speak when others may not even notice the change of quality in their voice.
For pure vocal tremor, I usually consider 3 medications.
- Inderal – (Propranalol) – up to 40 mg bid
- Mysoline – (Primidone) – start 25mg q hs
- Neurontin (gabapentin) – 300mg tid, may double – need good renal function
I typically start with propranolol unless the patient has specific problems, making use of this drug problematic. Some examples include an already low blood pressure, advanced age, asthma, certain heart problems or other conditions that propranolol may interact with.
Not everyone's tremor improves on this drug, so trial and error is the typical approach. Although people often respond at the 40 mg twice a day dose, I often start with the 10 mg twice a day dose, having the patient advance every few days up to the point where they feel the tremor is improved. It is certainly possible to go up to higher doses, if needed and if there are not mitigating side effects. The drug is unlikely to get rid of the tremor, only reduce the amplitude of oscillations of the voice.
In older patients or patients that fail to improve on propranolol, I consider using primidone or gabapentin.
Some more information is available on the We Move website.