title: Stop! border ahead: Automatic detection of subthalamic exit during deep brain stimulation surgery.
abstract: Microelectrode recordings along preplanned trajectories are often used for accurate definition of the subthalamic nucleus (STN) borders during deep brain stimulation (DBS) surgery for Parkinson's disease. Usually, the demarcation of the STN borders is performed manually by a neurophysiologist. The exact detection of the borders is difficult, especially detecting the transition between the STN and the substantia nigra pars reticulata. Consequently, demarcation may be inaccurate, leading to suboptimal location of the DBS lead and inadequate clinical outcomes.
  
  
  
  We present machine-learning classification procedures that use microelectrode recording power spectra and allow for real-time, high-accuracy discrimination between the STN and substantia nigra pars reticulata.
  
  
  
  A support vector machine procedure was tested on microelectrode recordings from 58 trajectories that included both STN and substantia nigra pars reticulata that achieved a 97.6% consistency with human expert classification (evaluated by 10-fold cross-validation). We used the same data set as a training set to find the optimal parameters for a hidden Markov model using both microelectrode recording features and trajectory history to enable real-time classification of the ventral STN border (STN exit). Seventy-three additional trajectories were used to test the reliability of the learned statistical model in identifying the exit from the STN. The hidden Markov model procedure identified the STN exit with an error of 0.04 ± 0.18 mm and detection reliability (error < 1 mm) of 94%.
  
  
  
  The results indicate that robust, accurate, and automatic real-time electrophysiological detection of the ventral STN border is feasible. © 2016 International Parkinson and Movement Disorder Society.
authors.affiliation: The Edmond and Lily Safra Center for Brain Research (ELSC), The Hebrew University, Jerusalem, Israel.|Department of Medical Neurobiology (Physiology), Institute of Medical Research - Israel-Canada (IMRIC), The Hebrew University-Hadassah Medical School, Jerusalem, Israel.
authors.forename: Dan
authors.initials: D
authors.lastname: Valsky
authors.affiliation: Department of Medical Neurobiology (Physiology), Institute of Medical Research - Israel-Canada (IMRIC), The Hebrew University-Hadassah Medical School, Jerusalem, Israel.
authors.forename: Odeya
authors.initials: O
authors.lastname: Marmor-Levin
authors.affiliation: Department of Medical Neurobiology (Physiology), Institute of Medical Research - Israel-Canada (IMRIC), The Hebrew University-Hadassah Medical School, Jerusalem, Israel.
authors.forename: Marc
authors.initials: M
authors.lastname: Deffains
authors.affiliation: Department of Psychiatry, Hadassah-Hebrew University Medical Center, Jerusalem, Israel.
authors.forename: Renana
authors.initials: R
authors.lastname: Eitan
authors.affiliation: Krasnow Institute for Advanced Study, George Mason University, Fairfax, Virginia, USA.
authors.forename: Kim T
authors.initials: KT
authors.lastname: Blackwell
authors.affiliation: The Edmond and Lily Safra Center for Brain Research (ELSC), The Hebrew University, Jerusalem, Israel.|Department of Medical Neurobiology (Physiology), Institute of Medical Research - Israel-Canada (IMRIC), The Hebrew University-Hadassah Medical School, Jerusalem, Israel.
authors.forename: Hagai
authors.initials: H
authors.lastname: Bergman
authors.affiliation: Center for Functional & Restorative Neurosurgery, Department of Neurosurgery, Hadassah-Hebrew University Medical Center, Jerusalem, Israel.
authors.forename: Zvi
authors.initials: Z
authors.lastname: Israel
mesh_terms: D000368:Aged; D046690:Deep Brain Stimulation / Q000379:methods*; D004567:Electrodes, Implanted; D055724:Electrophysiological Phenomena; D005260:Female; D006801:Humans; D008297:Male; D008390:Markov Chains; D008839:Microelectrodes; D008875:Middle Aged; D010300:Parkinson Disease / Q000601:surgery / Q000628:therapy*; D012815:Signal Processing, Computer-Assisted; D013378:Substantia Nigra / Q000033:anatomy & histology* / Q000502:physiology; D020531:Subthalamic Nucleus / Q000033:anatomy & histology* / Q000502:physiology; D060388:Support Vector Machine
keywords: Parkinson's disease; deep brain stimulation; microelectrode recording; substantia nigra; subthalamic nucleus