In selecting sites for a pallidotomy, Dr. Olanow of Mt. Sinai, commented at the March 7th Symposium that one should look for a teaching institution that uses microelectrode stimulation. How does microelectrode recording differ from electrical stimulation? The following article puts it in perspective. Microelectrode vs Electrical Stimulation in Pallidotomies -- Discussion Advanced Treatment for Parkinson's Disease Performed at Boston Hospital BOSTON, Jan. 22, 1996 -- Joining a handful of leading experts nationally, physicians from Boston's Beth Israel Hospital have performed their first pallidotomy guided by microelectrode recording on a patient with Parkinson's disease. The technique promises to be more accurate, more effective, and safer than the more commonly used "electrical stimulation" pallidotomy. Pallidotomy guided by microelectrode recording has produced an improvement in patients' symptoms that is twice as good initially, and about four times as good after one year, as pallidotomy guided by electrical stimulation. Parkinson's disease, a condition causing uncontrollable shaking and difficulty in initiating simple body movements, afflicts 500,000 to one million Americans, including U.S. Attorney General Janet Reno, who recently announced that she has been diagnosed with early signs of the disease. The goal of both types of pallidotomies is to destroy a pea-sized area in the brain that is responsible for producing Parkinson's disease symptoms. Physicians at Beth Israel Hospital used a technique of mapping the brain area that contains the overactive nerve cells that produce these symptoms. This is done by recording the activity of individual nerve cells through a tiny electrical probe called a microelectrode. "By recording the activity of single nerve cells, it is possible to identify and destroy only the targeted brain area and to distinguish it from neighboring areas that serve other critical functions. This precision brings unprecedented accuracy and reduces to a minimum the chances of producing unwanted damage to the patient," explains Rami Burstein, PhD, the neurophysiologist who performed the microelectrode recording. While pallidotomy guided by microelectrode recording identifies individual nerve cells associated with the patient's symptoms, the more commonly used electrical stimulation approach gives only a rough approximation of the brain area in which these nerve cells are located. Therefore, procedures using the more advanced pallidotomy technique are accurate to the thousandth of a millimeter, whereas procedures using electrical stimulation have the potential for missing the mark by several millimeters. Since the target is only four to six millimeters across, the improved accuracy results in better functional recovery for the patient. Burstein explains that in electrical stimulation pallidotomy, an electrical current is delivered in different brain areas through a stimulation probe. The main use of electrical stimulation is to find and avoid the borders of the optic tract, which controls vision, and the internal capsule, which is responsible for movement on the opposite side of the body. This technique cannot identify the key site for the pallidotomy directly, but does tell the surgeon when the probe is too close to the optic tract or the internal capsule. "The problem, however, is that it is impossible to know in which directions and to what distance the current spreads," says Burstein. "This introduces uncertainty as to the location of the probe in relation to the targeted nerve cells, and thus reduces the level of accuracy." "With the electrical stimulation approach, the surgeon tries to localize the site in the brain as much as you might try to find your way to the center of a darkened room by first feeling your way along the walls," explains Clifford B. Saper, MD, PhD, neurologist-in-chief at Beth Israel Hospital. Patients who benefit most from pallidotomy guided by microelectrode recording are those with advanced Parkinson's disease. In the early stages of the disease, medication can be used to control the symptoms. After many years, however, the medication often ceases to be effective. In addition to relieving much of the disease's effects, pallidotomy guided by microelectrode recording also enables the medication once again to regain effectiveness. "Pallidotomy using microelectrode recording requires state-of-the-art equipment and techniques normally used in research laboratories. What we have done here is to bring this technology directly into the operating room for the benefit of the patient," says David Dubuisson, MD, PhD, the neurosurgeon who performed the pallidotomy. The new technique of pallidotomy using microelectrode recording of nerve cells has been performed on about 200 patients across the country to date. The procedure requires a highly skilled neurophysiologist and a neurosurgeon with expertise in destroying targeted areas of the brain. Beth Israel Hospital's interdisciplinary team performing pallidotomies includes neurosurgeon David Dubuisson, MD, PhD, neurophysiologist Rami Burstein, PhD, and neurologist-in-chief Clifford Saper, MD, PhD. They join experts at only a handful of institutions nationally to use this technique successfully to treat Parkinson's disease. Beth Israel HealthCare is a regional system of care that includes individual physicians and medical groups, nurses, and other health professionals associated with Boston's Beth Israel Hospital, a major clinical, teaching, and research affiliate of Harvard Medical School. John Cottingham "The parkinsn list brings Knowledge, Comfort, Hope, and Homeboy Friendship to the parkinsonian world." LibraryH Parkinson's Chat on the Undernet 8:30 PM CST -6 Daily. If you access the Internet through a provider with a [log in to unmask] PPP/SLIP account, free IRC chat software is available. WFD