Shaking and quaking of the hands is the most common (and obvious) sign of essential tremor (ET). ET is the most prevalent movement disorder. Although it is considered non-life threatening, ET can gradually worsen to the point of delivering a crushing blow to a person’s control of their hands.
Another area affected is the voice, a problem for a quarter to a third of persons with ET. Uncontrollable rhythmic fluctuations can occur in the muscles of the tongue, throat, larynx, palate, or pharynx. A quavery voice can also result from muscle tremors in the chest wall and diaphragm, since breathing is part of vocal control. Trembling in any of these muscles can cause the voice to wobble or quaver. It can also cause difficulties with volume control (softer voice). There is no cure for voice tremors at this time.
Diagnosing ET-related voice tremors
Getting a correct voice tremor diagnosis is very important because incorrect diagnosis of ET often happens. Hand or head tremors may not accompany voice tremors, and family history may be unenlightening. Voice tremors also have other causes, most notably Parkinson’s disease (PD). ET tremors are considered action tremors because intentional movement triggers them, while PD-related tremors are considered resting tremors because they occur even without intentional movement. (However, many people with ET find that hand or other tremors continue even when they are still.)
In ET cases, talking makes voice tremors more pronounced, but even when the voice is at rest, a doctor can see tremors in the larynx with a visual scope, because the act of breathing still causes motion in the larynx. Here are some of the other conditions that cause voice tremors:
- Parkinson’s disease
- ALS (Lou Gehrig’s disease)
- Laryngeal dysphonia (including spasmodic dysphonia)
If a person has not yet been diagnosed with ET or other condition, a movement disorder specialist will first determine if ET is present based on a medical history, family history, and observation of movements. In addition, a special test called a laryngoscopy may be performed using a flexible scope so the doctor can do a visual assessment. Sometimes the scope exam includes a method for taking high resolution video images that allow for closer analysis if needed.
Treating vocal tremors
Medications such as propranolol or primidone that are often prescribed to help hand tremors are not helpful for voice tremors. Two management strategies, however, may help reduce speech quavers:
- Speech therapy does not stop the tremors, but offers training methods so the voice sounds smoother, has even volume, and words are clearer.
- Botulinum toxin (Botox) injections into the larynx can relax laryngeal muscles. However, this is not effective for everyone, and there is a risk of side effects that complicate swallowing.
MRI-guided Focused Ultrasound
The Sperling Neurosurgery Associates center offers MRI-guided Focused Ultrasound (MRgFUS) for the treatment of hand tremors in the dominant hand. Only the side of the brain that controls the dominant hand is treated because treating both sides (both hands) during the same treatment session has been shown to come with greater side effect risks.
At this time, there is no published research evidence that MRgFUS can help manage voice tremors. Our physicians and staff recognize the hardship and embarrassment that voice tremors can cause for those who have them. We follow research papers and presentations, because we share the hope that a noninvasive therapy such as MRgFUS can ultimately help those who live with them. We are optimistic that the efforts of science—hopefully in the near future—will generate a solution that works for everyone.