title: Beta oscillations in freely moving Parkinson's subjects are attenuated during deep brain stimulation.
abstract: BACKGROUND
  Investigations into the effect of deep brain stimulation (DBS) on subthalamic (STN) beta (13-30 Hz) oscillations have been performed in the perioperative period with the subject tethered to equipment. Using an embedded sensing neurostimulator, this study investigated whether beta power was similar in different resting postures and during forward walking in freely moving subjects with Parkinson's disease (PD) and whether STN DBS attenuated beta power in a voltage-dependent manner.
  
  
  METHODS
  Subthalamic local field potentials were recorded from the DBS lead, using a sensing neurostimulator (Activa(®) PC+S, Medtronic, Inc., Food and Drug Administration- Investigational Device Exemption (IDE)-, institutional review board-approved) from 15 PD subjects (30 STNs) off medication during lying, sitting, and standing, during forward walking, and during randomized periods of 140 Hz DBS at 0 V, 1 V, and 2.5/3 V. Continuous video, limb angular velocity, and forearm electromyography recordings were synchronized with neural recordings. Data were parsed to avoid any movement or electrical artifact during resting states.
  
  
  RESULTS
  Beta power was similar during lying, sitting, and standing (P = 0.077, n = 28) and during forward walking compared with the averaged resting state (P = 0.466, n = 24), although akinetic rigid PD subjects tended to exhibit decreased beta power when walking. Deep brain stimulation at 3 V and at 1 V attenuated beta power compared with 0 V (P < 0.003, n = 14), and this was voltage dependent (P < 0.001).
  
  
  CONCLUSIONS
  Beta power was conserved during resting and forward walking states and was attenuated in a voltage-dependent manner during 140-Hz DBS. Phenotype may be an important consideration if this is used for closed-loop DBS.
authors.affiliation: Department of Neurology and Neurological Sciences, Stanford University, Stanford, California, USA.
authors.forename: Emma J
authors.initials: EJ
authors.lastname: Quinn
authors.affiliation: Department of Neurology and Neurological Sciences, Stanford University, Stanford, California, USA.
authors.forename: Zack
authors.initials: Z
authors.lastname: Blumenfeld
authors.affiliation: Department of Neurology and Neurological Sciences, Stanford University, Stanford, California, USA.
authors.forename: Anca
authors.initials: A
authors.lastname: Velisar
authors.affiliation: Department of Neurology and Neurological Sciences, Stanford University, Stanford, California, USA.
authors.forename: Mandy Miller
authors.initials: MM
authors.lastname: Koop
authors.affiliation: Department of Neurology and Neurological Sciences, Stanford University, Stanford, California, USA.
authors.forename: Lauren A
authors.initials: LA
authors.lastname: Shreve
authors.affiliation: Department of Neurology and Neurological Sciences, Stanford University, Stanford, California, USA.
authors.forename: Megan H
authors.initials: MH
authors.lastname: Trager
authors.affiliation: Department of Neurology and Neurological Sciences, Stanford University, Stanford, California, USA.
authors.forename: Bruce C
authors.initials: BC
authors.lastname: Hill
authors.affiliation: Department of Neurology and Neurological Sciences, Stanford University, Stanford, California, USA.|Department of Neurosurgery, Stanford University, Stanford, California, USA.
authors.forename: Camilla
authors.initials: C
authors.lastname: Kilbane
authors.affiliation: Department of Neurology and Neurological Sciences, Stanford University, Stanford, California, USA.|Department of Neurosurgery, Stanford University, Stanford, California, USA.
authors.forename: Jaimie M
authors.initials: JM
authors.lastname: Henderson
authors.affiliation: Department of Neurology and Neurological Sciences, Stanford University, Stanford, California, USA.|Department of Neurosurgery, Stanford University, Stanford, California, USA.
authors.forename: Helen
authors.initials: H
authors.lastname: Brontë-Stewart
mesh_terms: D000328:Adult; D000368:Aged; D001611:Beta Rhythm / Q000502:physiology*; D046690:Deep Brain Stimulation; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000503:physiopathology* / Q000628:therapy*; D014851:Wakefulness / Q000502:physiology*
keywords: Parkinson's disease; deep brain stimulation; free walking; sensing neurostimulation; subthalamic nucleus