Benign Essential Tremor

Overview | Stroke | Parkinson’s Disease | Benign Essential Tremor (BET) | Amyotrophic Lateral Sclerosis |Myasthenia Gravis (MG) | Multiple Scleroris (MS) | Spasmodic Dysphonia

Image "A"Key Glossary Terms

Neurological Voice Disorders:
Voice problems caused by abnormal control, coordination, or strength of voice box muscles due to an underlying neurological disease such as: stroke, Parkinson’s disease, multiple sclerosis, myasthenia gravis, or ALS

Difficulty forming words – presenting with imprecise consonants and hard-to-understand speech as seen with stroke patients

Speech Disorder:
Malfunction of the tongue and/or lip muscles resulting in garbled words or parts or words.


What is benign essential tremor?
Tremor from Abnormal Muscle Contraction

BET is a neurologic disease that involves abnormal control of muscle contraction. The result is a “tremor” or shake of the involved muscle(s) either at rest or when the muscle(s) are in use. This often causes a periodic “shake” in the hand with and/or without use.

Voice Wobble or Shake in BET
BET can occur in the muscles of the palate, tongue, throat, and vocal folds. The result is an inability to keep the voice steady. Thus, the sound of the voice has a periodic (regular) wobble or shake.

What are the typical symptoms of voice dysfunction in patients with BET?
BET is one of the more common neurological disorders that can affect the voice. The symptoms that may be present are:

  • Tremor in the hands
  • Tremor involving the head
  • Shaky or tremulous voice

All three symptoms may be present, or only one may dominate.

What is the cause of BET?

Who is at risk?
As with most neurological disorders, the cause is not fully understood. BET is more common in females and often does not present until age 40 to 50. It may be hereditary in certain instances. No other risk factors are known.

How is BET diagnosed?
The diagnosis is most often made by careful history and physical examination by a neurologist.

Difficulties in Diagnosis

  • Without a laryngological examination, BET may be misdiagnosed by a neurologist if only vocal tremors are present and head and hand tremors are absent. In these cases, a fiberoptic laryngoscopy exam by a laryngologist/voice specialist may be needed to make the diagnosis.
  • Other neurological disorders may have tremor as a component and be mistaken for BET, especially in the case of adductor spasmodic dysphonia with tremor. (For more information, see Spasmodic Dysphonia.)
  • Other disorders such as Parkinson’s disease, ALS, and cerebellar ataxia may have vocal tremor as a component of the voice disorder but are rarely mistaken for BET.

How is BET treated?
Medications such as propranolol are sometimes employed to control the tremor, however they usually only have a mild effect on the vocal tremor. Botulinum toxin injection into the vocal folds may be attempted, but success is generally lower than that achieved for spasmodic dysphonia patients (usually 50 to 75 percent).

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Patient education material presented here does not substitute for medical consultation or examination, nor is this material intended to provide advice on the medical treatment appropriate to any specific circumstances.

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