title: Temporary deterioration of executive function after subthalamic deep brain stimulation in Parkinson's disease.
abstract: OBJECTIVE
  Selective impairment of executive function has been shown in Parkinson's Disease (PD) patients undergoing Deep Brain Stimulation (DBS) of the Subthalamic Nucleus (STN). However, some patients experience difficulties in daily life, such as dissension in interpersonal relationships or a loss of lifestyle balance, in the short term after surgery. Our hypothesis is that these difficulties might be related to executive dysfunction. To elucidate the involvement of executive dysfunction in these difficulties, we assessed motor and executive function in the short term and long term after surgery.
  
  
  METHODS
  We examined motor function and executive function in 30 patients who underwent bilateral STN-DBS for medically refractory PD. Patients were evaluated for executive function 1 month before surgery, 1 month after surgery, and 12 months after surgery using the Trail Making Test (TMT), the Modified Stroop Color Word Interference Test (MST) and tests of Verbal Fluency (VF).
  
  
  RESULTS
  TMT-B, TMT (B/A), MST-B, VF-phonemic and VF-semantic scores were significantly poorer 1 month after STN-DBS. TMT-B, TMT (B/A) and VF-phonemic recovered to preoperative levels by 12 months after surgery. A reduction in dopaminergic medication 1 month after surgery was significantly correlated with deterioration of TMT (B/A).
  
  
  CONCLUSIONS
  Temporary deterioration of executive function may occur in the short term after STN-DBS, whereas motor function is usually improved. PD patients undergoing STN-DBS should be managed during this period to better predict temporary executive dysfunction. Excessive reduction of dopaminergic medication after surgery might, at least in part, result in this deterioration of executive function.
authors.affiliation: Department of Neurology, Nagoya City University, 1 Kawasumi, Mizuho-ku, Nagoya 467-8601, Japan.
authors.forename: Takehiko
authors.initials: T
authors.lastname: Yamanaka
authors.forename: Fumiyasu
authors.initials: F
authors.lastname: Ishii
authors.forename: Atsushi
authors.initials: A
authors.lastname: Umemura
authors.forename: Miwako
authors.initials: M
authors.lastname: Miyata
authors.forename: Mitsuya
authors.initials: M
authors.lastname: Horiba
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Oka
authors.forename: Kazuo
authors.initials: K
authors.lastname: Yamada
authors.forename: Kenji
authors.initials: K
authors.lastname: Okita
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Matsukawa
authors.forename: Kosei
authors.initials: K
authors.lastname: Ojika
mesh_terms: D000368:Aged; D000978:Antiparkinson Agents / Q000627:therapeutic use; D003071:Cognition / Q000502:physiology; D046690:Deep Brain Stimulation / Q000009:adverse effects*; D015259:Dopamine Agents / Q000627:therapeutic use; D004567:Electrodes, Implanted; D056344:Executive Function / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009048:Motor Skills / Q000502:physiology; D009483:Neuropsychological Tests; D019635:Neurosurgical Procedures; D010300:Parkinson Disease / Q000150:complications / Q000523:psychology* / Q000628:therapy*; D057190:Stroop Test; D020531:Subthalamic Nucleus / Q000502:physiology*; D014145:Trail Making Test; D016896:Treatment Outcome; D014705:Verbal Behavior
chemical_list: D000978:Antiparkinson Agents; D015259:Dopamine Agents