Dear Doctors: I am considering an ultrasound treatment for essential tremor, which has affected my hands and also my voice. Can you please talk about tremor and about how this procedure works? Will it also help the tremor in my voice?
Dear Reader: Tremor is marked by uncontrolled trembling or shaking in one or more parts of the body. It can occur at any age and often interferes with quality of life.
The condition falls into several categories, based on the triggers that cause the tremor to occur. For example, kinetic tremor, or action tremor, takes place during movement. Postural tremor arises when a limb is braced against the forces of gravity, as when reaching out an arm or lifting or holding an object. Resting tremor isn't associated with movement at all; it occurs when the muscles are relaxed and at rest and stops as soon as they are engaged.
Essential tremor is the most common form of this disorder. It is estimated to affect up to 10 million people in the U.S. The condition is distinguished by the onset of a kinetic tremor that is not associated with any neurological issues. Although essential tremor usually involves the hands, it is possible for the neck, head, trunk, legs and voice to be affected as well. The cause remains unclear. However, there is evidence of a link to mild degeneration of tissues in the cerebellum. That's the region of the brain that oversees movement. Genetics also plays a role. In up to 70% of cases, there is a familial link to the condition.
Treatment typically begins with medications known as beta blockers. These can dampen errant neurological activity. If medications are unsuccessful, or when side effects outweigh their benefit, the ultrasound treatment you are considering may be an option. Known as focused or guided ultrasound, it is a noninvasive form of neurosurgery. The treatment uses pulses of focused sound waves to heat and destroy a cluster of cells within the brain. The "guided" part of this surgery involves magnetic resonance imaging, or MRI. The MRI is used to map the precise location of the targeted cells, and to monitor the path of the sound waves. During the course of the treatment, which takes several hours, patients perform movements that are used to assess the progress of the treatment.
Success rates vary, depending on the location and severity of each person's tremor. Studies show that in many people, existing tremors improve by 50% or more, and that gains last more than five years. This can include tremors of the voice. As with all medical procedures, there is a risk of adverse effects. Head pain and dizziness are the most commonly reported side effects of the treatment.
An MRI scanner is essentially a powerful magnet. That means the treatment isn't appropriate for people with certain metal and metallic surgical implants. It is also not recommended for anyone with claustrophobia. Some health conditions, including chronic infection, heart problems or being on dialysis, can also limit participation. Your doctor can help you learn if your medical situation makes you a candidate for this type of treatment.
(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)
