Implanted device can control tremors caused by Parkinson's and other conditions

Relief for persons afflicted by muscle tremors, including those related to Parkinson's disease, may now be available through a new surgical treatment.

The treatment involves surgically implanting a pacemaker-like device in the brain to deliver mild electrical stimulation. This stimulation, which can be controlled by the patient, blocks brain signals that cause muscle tremor.

“This therapy offers new hope for patients with tremor, either from essential tremor or from Parkinson's disease,” explains Dr. Sean Grady, UW professor of surgery who has performed the procedure at Harborview Medical Center.

Tremor is one symptom associated with Parkinson's disease, a progressive, degenerative disease affecting an estimated 500,000 Americans.

Essential tremor, a different diagnosis from Parkinson's disease, has as its only symptom a tremor that is generally worse during voluntary movement. An estimated 1 million people have essential tremor, which can vary from mild to disabling.

“Tremor can severely affect a person's quality of life, as well as his or her ability to function,” Grady says.

The cause of both Parkinson's and essential tremor is unknown; and in most cases, tremors are treated reasonably well with medication. Some individuals, however, fail to respond to medical treatment or have serious side effects from the medication.

Grady notes the new therapy has a potential to help a significant number of individuals in both groups.

The device includes an insulated wire lead that is surgically implanted deep within the thalamus, the brain's communication center. The lead is connected by an extension wire passed under the skin to an implanted pulse generator, similar to an advanced cardiac pacemaker. Patients control the stimulation by passing a hand-held magnet over the implant's pulse generator to turn it on or off, or to vary stimulation depending on their need to suppress tremors.

A number of medical centers throughout the country now offer this surgical treatment.

“Many people live with tremor because they believe nothing further can be done,” Grady says. “Now we can offer them an alternative.”

The device, called the Activa Tremor Control System, is developed by Medtronic,Inc. ¶

Julie Rathbun