Medical Health Encyclopedia

The generator must be replaced every three to five years.

Deep brain stimulation (DBS) has been intensively studied during the past five years, and much has been learned about how DBS affects the underpinnings of Parkinson's disease. This knowledge has enabled physicians to apply DBS to other areas of the brain and successfully treat greater numbers of patients. Two new DBS devices received FDA approval in 2003.

Neurostimulation of the Subthalamic Nucleus (STN Stimulation). Bilateral subthalamic nucleus (STN) stimulation employs double (bilateral) implants in the subthalamic nucleus, which controls symptoms of rigidity and involuntary motion.

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STN stimulation is proving to improve gait, walking ability, and upper limb rigidity in some patients. Its affect on gait, however, may differ from the effects of L-dopa. One study suggested that although improvement occurred, patients did not walk as quickly nor was the stride as long as those on L-dopa. The procedure does not improve gait in patients who do not respond to L-dopa, nor does it help freezing or speech disorders. To date, candidates are generally under 70 who have motor fluctuations, drug-induced dyskinesia, and no other serious medical or psychiatric conditions. Researchers are trying to determine if more patients can be suitable candidates.

Complications. Complications occur in 2% to 4% of operations. The most serious ones are bleeding in the brain and infection. Depression is common. A 2001 study reported a moderate decrease in verbal memory and mental tasks involving visual-spatial functions. (Some other mental functions improved.) Some experts are not convinced of the safety of implanting a polyurethane device in the brain.

Neurostimulation of the Thalamus. Neurostimulation of thalamus helps patients with tremor. Studies are reporting improvement in tremor in up to 85% of patients, although only on one side of the body. Long-term effects are still unknown, although studies are indicating that it is safe and effective.

Pallidotomy and Other Procedures that Destroy Tissue