Iowa gambling task impairment in Parkinson's disease can be normalised by reduction of dopaminergic medication after subthalamic stimulation

J Neurol Neurosurg Psychiatry. 2015 Feb;86(2):186-90. doi: 10.1136/jnnp-2013-307146. Epub 2014 May 23.


Background: Impulse control disorders (ICD), including pathological gambling, are common in Parkinson's disease (PD) and tend to improve after subthalamic (STN) stimulation after a marked reduction of dopaminergic medication. In order to investigate the effect of STN stimulation on impulsive decision making, we used the Iowa Gambling task (IGT).

Methods: We investigated IGT performance in 20 patients with PD before STN surgery with and without dopaminergic treatment and in 24 age-matched controls. All patients underwent an extensive neuropsychological interview screening for behavioural disorders. Assessment in patients was repeated 3 months after surgery without dopaminergic treatment with and without stimulation.

Results: Chronic antiparkinsonian treatment was drastically reduced after surgery (-74%). At baseline, on high chronic dopaminergic treatment 8/20 patients with PD presented with pathological hyperdopaminergic behaviours, which had resolved in 7/8 patients 3 months after surgery on low chronic dopaminergic treatment. Preoperative performance on the IGT was significantly impaired compared to after surgery.

Conclusions: Dopaminergic medication likely contributes to the impairment in decision making underlying ICDs. Deep brain stimulation allows drastic reduction of dopaminergic medication and, thus, concomitant remediation of medication-induced impairment in decision making.

Keywords: Iowa Gambling Task; Parkinson's disease; decision making; dopamine; impulse control disorder; subthalamic nucleus.

Publication types

  • Observational Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Case-Control Studies
  • Deep Brain Stimulation*
  • Disruptive, Impulse Control, and Conduct Disorders / complications
  • Disruptive, Impulse Control, and Conduct Disorders / psychology*
  • Disruptive, Impulse Control, and Conduct Disorders / therapy*
  • Dopamine Agents / administration & dosage*
  • Dopamine Agents / therapeutic use
  • Female
  • Gambling / psychology
  • Humans
  • Male
  • Middle Aged
  • Neuropsychological Tests
  • Parkinson Disease / complications
  • Parkinson Disease / drug therapy
  • Parkinson Disease / psychology*
  • Parkinson Disease / therapy*
  • Psychomotor Performance / drug effects
  • Subthalamic Nucleus / physiology*


  • Dopamine Agents