title: Unilateral subthalamic nucleus stimulation has a measurable ipsilateral effect on rigidity and bradykinesia in Parkinson disease.
abstract: BACKGROUND
  Bilateral deep brain stimulation (DBS) of the subthalamic nucleus (STN) improves motor function in Parkinson disease (PD). However, little is known about the quantitative effects on motor behavior of unilateral STN DBS.
  
  
  METHODS
  In 52 PD subjects with STN DBS, we quantified in a double-blinded manner rigidity (n=42), bradykinesia (n=38), and gait speed (n=45). Subjects were tested in four DBS conditions: both on, left on, right on and both off. A force transducer was used to measure rigidity across the elbow, and gyroscopes were used to measure angular velocity of hand rotations for bradykinesia. About half of the subjects were rated using the Unified Parkinson Disease Rating Scale (part III) motor scores for arm rigidity and repetitive hand rotation simultaneously during the kinematic measurements. Subjects were timed walking 25 feet.
  
  
  RESULTS
  All subjects had significant improvement with bilateral STN DBS. Contralateral, ipsilateral and bilateral stimulation significantly reduced rigidity and bradykinesia. Bilateral stimulation improved rigidity more than unilateral stimulation of either side, but there was no significant difference between ipsilateral and contralateral stimulation. Although bilateral stimulation also increased hand rotation velocity more than unilateral stimulation of either side, contralateral stimulation increased hand rotation significantly more than ipsilateral stimulation. All stimulation conditions improved walking time but bilateral stimulation provided the greatest improvement.
  
  
  CONCLUSIONS
  Unilateral STN DBS decreased rigidity and bradykinesia contralaterally as well ipsilaterally. As expected, bilateral DBS improved gait more than unilateral DBS.
authors.affiliation: Department of Neurology, Washington University in St. Louis, 4525 Scott Avenue, St. Louis, MO 63130, USA.
authors.forename: Samer D
authors.initials: SD
authors.lastname: Tabbal
authors.forename: Mwiza
authors.initials: M
authors.lastname: Ushe
authors.forename: Jonathan W
authors.initials: JW
authors.lastname: Mink
authors.forename: Fredy J
authors.initials: FJ
authors.lastname: Revilla
authors.forename: Angie R
authors.initials: AR
authors.lastname: Wernle
authors.forename: Minna
authors.initials: M
authors.lastname: Hong
authors.forename: Morvarid
authors.initials: M
authors.lastname: Karimi
authors.forename: Joel S
authors.initials: JS
authors.lastname: Perlmutter
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D046690:Deep Brain Stimulation / Q000379:methods*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D005684:Gait / Q000502:physiology / Q000528:radiation effects; D006801:Humans; D018476:Hypokinesia / Q000209:etiology / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D009127:Muscle Rigidity / Q000209:etiology / Q000628:therapy*; D010300:Parkinson Disease / Q000150:complications; D020531:Subthalamic Nucleus / Q000503:physiopathology* / Q000528:radiation effects