title: Low-frequency versus high-frequency subthalamic nucleus deep brain stimulation on postural control and gait in Parkinson's disease: a quantitative study.
abstract: BACKGROUND
  High frequency stimulation (HFS) of the subthalamic nucleus (STN-DBS) has been shown to have little impact on postural control and gait improvements in Parkinson's disease (PD). There is a lack of consensus and quantitative evidence to suggest that stimulating STN at a lower frequency (LFS) as compared to HFS will be superior in improving symptoms.
  
  
  OBJECTIVE
  To determine if postural control and gait characteristics of persons with PD improve at an LFS (60 Hz) compared to HFS (>100 Hz). We hypothesized that persons with PD would perform better on postural control and gait measures at LFS.
  
  
  METHODS
  Nineteen participants with bilateral STN-DBS underwent UPDRS, static and dynamic postural control using gait initiation, and gait evaluations in three stimulation conditions (baseline voltage stable across conditions: OFF, LFS of 60 Hz, and HFS of >100 Hz). Additionally 10/19 participants were also stimulated at 30 Hz and 60 Hz and at higher voltages. A one-way ANOVA was performed to compare the conditions.
  
  
  RESULTS
  Total UPDRS-III score, step length and velocity during gait initiation, and gait speed significantly improved during 60 Hz and >100 Hz conditions when compared to the OFF condition (P < 0.05). There were no significant differences between 60 Hz and >100 Hz conditions. Using LFS at higher voltage showed no improvement over >100 Hz condition.
  
  
  CONCLUSIONS
  The positive effects of both LFS and HFS on postural control and gait were similar and clinical changes were relatively small. LFS may not help improve postural control, and gait particularly for persons with PD who do not develop gait-related disorders after HFS.
authors.affiliation: Department of Physical Therapy Education, Elon University, Elon, NC, USA. Electronic address: svallabhajosula@elon.edu.
authors.forename: Srikant
authors.initials: S
authors.lastname: Vallabhajosula
authors.affiliation: Department of Neurology, Wake Forest School of Medicine, Winston Salem, NC, USA.
authors.forename: Ihtsham U
authors.initials: IU
authors.lastname: Haq
authors.affiliation: Division of Neurology, Scripps Clinic Torrey Pines, La Jolla, CA, USA.
authors.forename: Nelson
authors.initials: N
authors.lastname: Hwynn
authors.affiliation: Department of Neurology, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: Genko
authors.initials: G
authors.lastname: Oyama
authors.affiliation: Departments of Neurology, Neurosurgery, Neuroscience, Psychiatry and History, University of Florida, Gainesville, FL, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Okun
authors.affiliation: Department of Kinesiology and Health Promotion, Troy University, Troy, AL, USA.
authors.forename: Mark D
authors.initials: MD
authors.lastname: Tillman
authors.affiliation: Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA.
authors.forename: Chris J
authors.initials: CJ
authors.lastname: Hass
mesh_terms: D000328:Adult; D000368:Aged; D046690:Deep Brain Stimulation / Q000379:methods*; D005260:Female; D005684:Gait / Q000502:physiology*; D020233:Gait Disorders, Neurologic / Q000150:complications / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000150:complications / Q000503:physiopathology / Q000628:therapy*; D004856:Postural Balance / Q000502:physiology*; D012720:Severity of Illness Index; D020531:Subthalamic Nucleus / Q000502:physiology*
keywords: Deep brain stimulation; Gait; Gait initiation; Parkinson's disease; Postural control; Variability