What is essential voice tremor?
Essential tremor is a disease of involuntary movement. It causes the affected body part – most often the arms and hands – to shake while a person is attempting to do something with it. This can make it difficult to write, handle eating utensils, or perform other necessary day-to-day activities. Essential tremor can also involve the larynx, vocal folds and throat, causing changes in the voice.
The cause of essential tremor is unknown. In about half of cases, it is inherited from a parent. Essential tremor tends to worsen with age.
What are the symptoms of essential voice tremor?
Essential vocal tremor causes rhythmic changes in voice which vary in severity. In cases of mild tremor, there might only be minor quavering in the voice. More severe tremor can actually cause interruptions in voice. The key feature is that the variations in loudness (and sometimes in pitch) caused by tremor are rhythmic and are always present, no matter what type of vocalizing is being done. Persons with voice tremor may adopt whispering as a standard mode of speaking, since it masks these variations.
What does essential voice tremor look like?
Essential tremor is a rhythmic, alternating contraction of opposing muscles. This results in oscillatory movement of the affected body part. When tremor affects the voice, it usually involves not only the vocal folds, but also the muscles of the pharynx , back of the tongue and palate. The vocal cords flutter open and closed during voicing, and also sometimes during quiet breathing. The cycle typically occurs four to twelve times per second. This motion is synchronized with similar muscle activity in all affected areas.
There is no specific test to diagnose essential voice tremor. Diagnosis is based on the observation of the typical vocal cord movements during voicing. The presence of essential tremor in the head or the hands is suggestive as well, although it is not required to make the diagnosis. It is not widely known, even among doctors, that essential tremor may affect only the voice.
How is essential voice tremor treated?
There is no generally accepted treatment for essential voice tremor. Usually, the choice lies between medication and injections of botulinum toxin. Voice therapy typically offers little relief, since the vocal fold motion is involuntary.
When it affects other parts of the body, essential tremor sometimes responds to medication. Propranolol, which is usually used to control blood pressure, and primidone, which is a seizure medication, are common prescription drugs used for treatment. Neither of these has been clearly shown to help people with essential voice tremor in studies, but they may help in individual cases. Each has important side effects that should be discussed with a physician prior to use.
Botulinum toxin is a naturally-occurring substance which weakens muscle. In laryngology , it enjoys its greatest use in the treatment of spasmodic dysphonia. It can be helpful in severe cases of essential tremor. It is injected into the vocal folds though the skin of the neck and helps to even out the voice and make speaking less effortful. The effect is temporary and injections need to be repeated every three or four months. While its effect in essential tremor is not as dramatic and complete as it is in spasmodic dysphonia, some people benefit a great deal.
Individuals with essential voice tremor are probably best advised to discuss the treatment options with a neurologist, who will probably be able to give them the best and latest information on available medication, and an otolaryngologist who is able to inform them regarding botulinum toxin injections. It is important to understand that neither treatment cures the tremor, but simply helps with its symptoms.