When medications fail, many individuals with Parkinson's disease turn to deep brain stimulation (DBS). Yet while DBS often proves effective in relieving the movement problems associated with Parkinson's, it can have negative effects on cognition. The reasons for these effects - good and bad - are poorly understood.
Joel Perlmutter, M.D., a professor of neurology and radiology at Washington University in St. Louis, theorizes that the effectiveness of DBS could be improved and its side effects reduced by targeting the stimulation to one key site in the brain and avoiding a nearby site only a few millimeters away. He is investigating that theory with funding from the National Institute of Neurological Disorders and Stroke (NINDS), provided through the American Recovery and Reinvestment Act (ARRA).
DBS involves surgically implanting electrodes within deep brain structures that help control movement, and delivering stimulation through the electrodes with a pacemaker-like device. One common target is the subthalamic nucleus (STN). Some studies suggest that stimulating the dorsal part (top) of the STN leads to desirable activity in the brain's motor pathways, while stimulating the ventral part (bottom) leads to undesirable activity in other brain pathways that are involved in cognition.
Dr. Perlmutter and his team plan to examine Parkinson's patients who have received DBS to the STN, and to pinpoint the location of the electrodes - which can change post-operatively. They'll analyze how electrode location affects the patients' motor symptoms, cognitive function and cortical activity. To precisely locate the electrodes, the team pioneered a method that involves reconstructing 2-D brain scans into 3-D maps, and using landmarks in and around the STN for orientation.
This research should lead to a better understanding of how DBS works and improvements in using it to treat Parkinson's, including better design and targeting of the electrodes. Beyond that, it is expected to yield insights into the function of the STN and its involvement in other neurological disorders.Image caption: The CT scan shows two electrodes implanted in the brain and the difficulty of determining the precise locations of their tips. Courtesy of Dr. Perlmutter, and published in the Journal of Neuroscience Methods, Vol. 168. pp. 275-281, 2008.
NINDS (www.ninds.nih.gov) is the nation's primary supporter of biomedical research on the brain and nervous system.
More information about NIH's ARRA grant funding opportunities can be found at http://grants.nih.gov/recovery/. To track the progress of HHS activities funded through the ARRA, visit www.hhs.gov/recovery. To track all federal funds provided through the ARRA, visit www.recovery.gov.
Last updated March 20, 2013