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EMBARGOED FOR RELEASE: April 28, 1998
Comprehensive Epilepsy Program Offers Two New Alternatives For Patients With Uncontrolled Seizures
Physician-scientists in the Comprehensive Epilepsy Program of the Medical College of Wisconsin and Froedtert Hospital are at the forefront of clinical research and development of new surgical and mechanical treatment options to help the more than 500,000 U.S. epilepsy patients whose seizures cannot be controlled by medications.
The new options are "awake" surgery and a new battery-powered "pacemaker" implant that stimulates the vagal nerve at the base of the neck. Awake surgery leaves 60 to 80 percent of the patients who qualify for it seizure free. The vagal nerve stimulation (VNS) device reduces the frequency and/or intensity of uncontrolled seizures by more than 50 percent in over one-third of the patients using it.
Medical College physicians at Froedtert are currently the only ones in Wisconsin offering "awake" surgery for epilepsy patients. Working with a team of Medical College neurologists, radiologists and biophysicists, Wade Mueller, M.D., associate professor of neurosurgery, has performed 150 of these procedures since 1991.
Candidates for the surgery are those whose uncontrolled seizures alter consciousness levels and are confined to one specific area of the brain. Careful monitoring and testing are vital to localizing the trouble spot and assure the success and safety of this surgery. In a special intensive monitoring unit at Froedtert, EEG brain wave activity is recorded around-the clock, with simultaneous video taping to capture seizure activity. Patients also undergo computed tomography, MRI, Functional MRI and neurological testing to localize the affected area. Since the brain feels no pain, patients are awake during the surgery. This provides the neurosurgeon with immediate detection of any disturbance in vital motor or cognitive regions of the brain, in order to avoid them while delicately removing the region of seizure activity.
Also, the Comprehensive Epilepsy Program was one of only 15 sites in the U.S. to participate in clinical trials of an implanted vagal nerve stimulation (VNS) device which began in 1994. George Morris, M.D., associate professor of neurology and director of the Comprehensive Epilepsy Program, will present the findings of these national clinical trials at the annual meeting of the American Academy of Neurology on April 28. Since 1994, he has implanted over two dozen VNS devices, more than any other physician in the nation.
The national study of 244 patients receiving implants between 1994 and 1997 reveals long-term data. One-third of these patients had a greater than 50 percent reduction in seizure frequency and/or intensity within one year of implantation. Well over one-third enjoyed a more than 50 percent reduction by the second year and, to date, more than one-third continue to enjoy that level of relief in their third year.
While the VNS device is the first entirely new treatment option for epilepsy approved by the FDA in the past 100 years, how or why VNS works remains unclear.
That's what Dr. Morris wants to know and why he has called on the Medical College of Wisconsin's Biophysics Research Institute to help him conduct the world's first functional magnetic resonance imaging (FMRI) studies of the device at work during seizure activity.
Knowing how VNS works could mean knowing how to help more of these patients, who are not candidates for surgery because their uncontrolled seizures are not localized in a specific area of the brain. "We are very fortunate to have the resources and expertise of the Center for this study," Dr. Morris Said. "These researchers were among the first in the world to develop the functional MRI brain imaging technique. With this non-invasive and extremely accurate method of brain function imaging, we hope to learn which brain structures are activated by vagal nerve stimulation, which levels of stimulation are most effective and why VNS works better for some patients than others." He anticipates completion of this study by early August.
FMRI reveals the precise location of brain activity in real time by rapidly detecting increases in oxygen levels of brain cells. Medical College Biophysics Research Center physicians and scientists from many specialties are currently conducting cooperative studies that range from the mapping of the visual, auditory and motor cortex to understanding brain activity involved in language, memory, Alzheimer's Disease, dyslexia and drug addiction. The NeuroCybernetic Prosthesis VNS device is made by Cyberonics, Inc. of Webster, Tex., and can be implanted in one to two hours in an outpatient procedure. A pulse generator is inserted under the skin on the chest and the lead wire is then tunneled to the lower portion of the neck where it is wrapped around the left vagus nerve. It can then be programmed externally to set the sequence. Most commonly, it is set to deliver electrical pulses for 30 seconds, every five minutes, 24 hours per day. Also, patients who experience a warning "aura" can activate the device manually, with a magnet, to potentially prevent an on-coming seizure.
Dr. Morris' co-investigators for this study are: Roy Sucholeiki, M.D., an epilepsy fellow in the department of neurology, and Victor Haughton, M.D., professor of radiology.
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