Automatic intra-operative localization of STN using the beta band frequencies of microelectrode recordings

Deep brain stimulation (DBS) is considered a surgical treatment alternative for Parkinson disease (PD) patients with intractable tremor or for those patients who are affected by long-term complications of levodopa therapy such as motor fluctuations and severe dyskinesias. However, the susceptible accuracy of placement of the DBS electrode inside the brain nucleus determines the therapeutic efficacy of the method. Unlike normal cases, untreated Parkinsonian states in basal ganglia structures produce oscillations at various frequencies, the most prominent of which is a synchronization in the beta frequency band recorded in the subthalamic nucleus (STN). The actual frequency range and the strength of the beta peak vary among patients. We propose that an on-line spectral analysis of the population activity, as evidenced by microelectrode recordings (MERs) could form a neurophysiological biomarker for confirmation of the on-target placement of the electrode within the STN.