Applications of decision support systems in functional neurosurgery

Functional neurosurgery is used for treatment of conditions in central nervous system that arise from its improper physiology. One of the possible approaches is Deep Brain Stimulation (DBS). In this procedure a stimulating electrode is placed in desired brain’s area to locally affect its activity. Among others, DBS can be used as a treatment for dystonia, depression, obsessive-compulsive disorder (OCD) and Parkinson’s Disease (PD). In this paper authors focus on application of classifiers in Deep Brain Stimulation (DBS) for Parkinson’s Disease (PD). In neurosurgical treatment of the Parkinson’s Disease the target is a small (9 x 7 x 4 mm) deeply in brain situated structure called Subthalamic Nucleus (STN). The goal of the Deep Brain Stimulation is the precise permanent placement of the stimulating electrode within target nucleus. As this structure poorly visible in CT or MRI it is usually stereotactically located using microelectrode recording. Several microelectrodes are parallelly inserted into the brain and then in measured steps advanced towards expected location of the nucleus. At each step, usually from 10 mm above expected center of the STN, the neuronal activity is recorded. Because STN has a distinct physiology, the signals recorded within it also present specific features. By extraction certain attributes from recordings provided by the microelectrodes, it is possible to construct a binary classifier that provides useful discrimination. This discrimination divides the recordings into two classes, i.e. those registered within the STN and those registered outside of it. From this it is known which microelectrodes and at which depths have passed through the STN and thus a physiological map of its surrounding is made.