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---------------------------------------------------------------------------- FDA approves powerful brain implant to cut tremors ---------------------------------------------------------------------------- Copyright 1997 Nando.net Copyright 1997 The Associated Press WASHINGTON (August 4, 1997 11:27 a.m. EDT) -- The Food and Drug Administration Monday approved a pacemaker-like brain implant to help people with Parkinson's disease and other tremor disorders literally cut off their uncontrollable shaking. Medtronic Corp.'s Activa system provides "deep brain stimulation." It involves drilling through the skull to implant an electrode in the brain that emits constant, customized electric shocks to block tremors. Activa helps control the debilitating shakes that accompany Parkinson's disease and a little-understood hereditary disease called essential tremor. It "will enable patients with essential tremor to once again perform daily living activities unaided, and may improve these activities somewhat in people with Parkinson's disease," said FDA Acting Commissioner Michael Friedman. Up to 1.5 million Americans have Parkinson's disease, a degenerative neurological disease where patients suffer shaking along with rigid limbs and other worsening symptoms. About 2 million Americans have essential tremor, which causes similar violent shaking but no other symptoms. The drug L-Dopa helps some Parkinson's symptoms, although its effects wane over time. Only about 40 percent of essential tremor patients are helped with medicines. The shaking is so debilitating -- eventually destroying patients' ability to work, even feed themselves -- that some undergo dangerous surgery to destroy a small part of the brain responsible for the trembling. But the surgery can cause permanent problems with speech, movement and swallowing. The Activa brain implant promises to be less risky. In a study of 113 severe Parkinson's patients and 83 severe essential tremor patients, almost everyone experienced a reduction in tremors. Tremors were significantly reduced in 58 percent of essential tremor patients and 67 percent of Parkinson's patients. The effect was greatest for essential tremor, where testing showed patients could write, pour liquids without spilling and perform other tasks significantly better after the implant. Parkinson's patients' trembling also was eased, but the implant didn't help other symptoms such as the rigidity that also impedes their ability to write and perform other tasks. The implant stimulates one side of the brain to cut tremors on one side of the body. It would take two implants, on each side of the brain, to cut the shaking of both hands. The FDA approved only one implant Monday, postponing its decision on whether a double implant is safe until Medtronic finishes further studies. The FDA also required Medtronic to study the long-term effects of constant electrical stimulation on brain tissue. The FDA warned that the Activa system does have some side effects. About one-third of patients experience a tingling sensation in the head and hands, although doctors could minimize the effect by changing the shock emissions on their electrode. Also, the electrode is powered by a pacemaker-sized "pulse generator" that is implanted under the collarbone and must be surgically replaced every three to five years when the battery expires. <http://www.nando.net/newsroom/ntn/health/080497/health19_22136.html> ------------------------------------------------------------------------ [log in to unmask]