title: Localization of the subthalamic nucleus in Parkinson disease using multiunit activity.
abstract: BACKGROUND
  Refinement of the subthalamic nucleus (STN) coordinates using intraoperative microelectrode recordings (MER) is routinely performed during deep brain stimulation (DBS) surgeries in Parkinson disease (PD). The commonly used criteria for electrophysiological localization of the STN are qualitative. The goal of this study was to validate quantitative STN detection algorithm (QD) derived from the multi-unit activity in a prospective setting.
  
  
  METHODS
  Ten PD patients underwent STN DBS surgery. The MUA was obtained by removing large spikes close to microelectrode using wavelet method and integrating the 500-2000Hz band in the power spectral density. The qualitative intraoperative mapping of the STN using MER (IOM) versus QD was compared using Bland-Altman and Pearson's correlation analysis.
  
  
  RESULTS
  The clinical efficacy was confirmed in all subjects. The mean difference between IOM and QD of the dorsal/ventral border was 0.31±0.84/0.44±0.47mm. Using Bland-Altman statistic, only 2/36 (5.6%) differences (one for the dorsal border and one for the ventral border) were out of ±2 sd line of measurement differences. Correlation between dorsal border/ventral border positions obtained by IOM and QD was 0.79, p<0.0001/0.91, p<0.0001.
  
  
  CONCLUSIONS
  Both methods are in reasonable agreement and are strongly correlated. The QD gives objective coordinates of the STN borders at high precision and may be more accurate than IOM. Prospective blinded comparative studies where the DBS leads will be placed using either QD or IOM are warranted.
authors.affiliation: Dept. of Neurology, University of Massachusetts Medical School, MA 01655, USA. novakp@ummhc.org
authors.forename: Peter
authors.initials: P
authors.lastname: Novak
authors.forename: Andrzej W
authors.initials: AW
authors.lastname: Przybyszewski
authors.forename: Andrei
authors.initials: A
authors.lastname: Barborica
authors.forename: Paula
authors.initials: P
authors.lastname: Ravin
authors.forename: Lee
authors.initials: L
authors.lastname: Margolin
authors.forename: Julie G
authors.initials: JG
authors.lastname: Pilitsis
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000328:Adult; D000368:Aged; D001931:Brain Mapping; D046690:Deep Brain Stimulation / Q000379:methods*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008839:Microelectrodes; D008875:Middle Aged; D010300:Parkinson Disease / Q000503:physiopathology* / Q000628:therapy*; D011446:Prospective Studies; D016037:Single-Blind Method; D020531:Subthalamic Nucleus / Q000502:physiology*