title: Strategy instruction in Parkinson's disease: influence on cognitive performance.
abstract: OBJECTIVE
  Though strategic deficits are extensively investigated in Parkinson's disease (PD), little is known about the effects of instruction for PD patients. Thus, we compared the ability to internally generate a cognitive strategy with the ability to use a strategy after elaborate strategy instruction.
  
  
  METHODS
  Patients with PD (n=14) and matched healthy controls (n=22) were administered a Numerosity Judgement task in which they had to determine different numerosities of blocks presented in a square grid. In more complex task configurations, healthy participants tend to use a subtraction strategy. Participants in our study were confronted with a counting condition (A), a strategy initiation condition without instruction (B), and a strategy elaboration and strategy training condition (C).
  
  
  RESULTS
  Patients and controls were comparable with respect to basic cognitive measures. PD patients and controls performed equivalently within the counting condition (A), but patients needed significantly more trials to initiate the subtraction strategy. With the exception of 1 PD patient, all patients were able to internally initiate the strategy (condition B). In condition C, both groups increased reaction times, but patients were significantly slower than controls. Moreover, only patients significantly increased error rates after strategy instruction.
  
  
  CONCLUSIONS
  As long as sufficient time is provided for solving the task, results do not show a general deficit in the ability to internally generate a cognitive strategy in PD. Failures in strategy utilization strongly depend on cognitive load (working memory, executive functions). This bears important implications for the neuropsychological rehabilitation of PD patients.
authors.affiliation: Department of Neurosurgery, University Hospital Schleswig-Holstein, Kiel, Germany. goebels@nch.uni-kiel.de
authors.forename: Simone
authors.initials: S
authors.lastname: Goebel
authors.forename: Hubertus Maximilian
authors.initials: HM
authors.lastname: Mehdorn
authors.forename: Bernd
authors.initials: B
authors.lastname: Leplow
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D003072:Cognition Disorders / Q000209:etiology*; D005260:Female; D006801:Humans; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology; D008875:Middle Aged; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000150:complications*; D010364:Pattern Recognition, Visual / Q000502:physiology; D010775:Photic Stimulation / Q000379:methods; D011340:Problem Solving / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D021641:Recognition, Psychology / Q000502:physiology; D013223:Statistics as Topic; D011795:Surveys and Questionnaires