[The deficit of decision-making in Parkinson's disease]

To investigate the characteristics of decision-making impairment in Parkinson's disease (PD) patients.

A total of 20 individuals with idiopathic PD were compared with matched health controls on the Iowa Gambling Task, A series of battery including the assessment working memory, visual spatial ability and verbal fluency was also administered. The severity of disease was assessed based on the Hohen and Yahr scale.

The results showed that PD group impaired on verbal fluency, working memory and decision-making task. In Iowa gambling task, the PD group selected more disadvantageous cards than health controls (51.6 +/- 5.8, 46.8 +/- 8.2 respectively), the difference between two groups is significant (t((38)) = 2.12, P = 0.04). A 2 (group) x 5 (block) ANOVA (analysis of variance) on the scores of advantageous from the gambling task revealed a significant main effect of group (F((1, 38)) = 6.16, P = 0.01). The ANOVA also revealed a significant main effect of block (F((4, 152)) = 2.43, P = 0.04). The results showed that health controls gradually shifted their selections toward the good decks as the game progresses, but the PD group did not exhibit this stable advantageous shift in decision-making. Meanwhile, the study indicated the total number of disadvantageous cards for PD was positive correlation to the degrees of severity to clinical symptom.

The present study suggests that the decision-making impairment might be in early PD. The deficit of decision-making for PD might be attributed to the dysfunction of the orbito-frontal cortex.