Effects of dopaminergic medication on decision-making under ambiguity in patients with early Parkinson's disease

Abstract

Objective To investigate the effects of dopaminergic medication on decision-making under ambiguity in patients with early Parkinson's disease(PD). Methods Using Iowa Gambling Task (IGT) for 24 early non-medication idiopathic PD patients(Hoehn and Yahr Scale≤Ⅱlevel), 24 early idiopathic PD patients with regular dopaminergic medication and also for 24 healthy controls(HC) whose age, gender, and education match to PD patients to test their ability of decision-making under ambiguity. Results The results showed non-medication PD group showed impairments on digtal span and verbal fluency and decision-making task. There was significant difference in IGT task scores among the three groups(F=6.024, P=0.004). The total net scores of advantageous choices in IGT were significantly lower in non-medication PD group((-4.50±22.19) scores) than medication PD group((8.83±23.24)scores) and healthy group((15.92±15.77)scores). The difference of net scores in block1 to block5 between non-medication PD group and medication PD group was gradually increased, and the difference of net scores in block5 was significant(P 0.05). As the game processing, medication PD group gradually shifted their selections toward the advantageous choices. But non-medication group did not exhibit this shift pattern and the performance was much poorer. Meanwhile, the study also indicated the total net scores of advantageous choices for non-medication PD group was positive correlation to the MoCA scores (r=0.614, P=0.001). Conclusion The present study has shown that non-medication PD group has impairment in decision-making under ambiguity risk condition and prefer to choose risky options. when exogenous complement dopaminergic medication, the risk decision-making ability of medication PD group has been improved. Key words: Parkinson's disease; Decision-making under ambiguity; Cognition; Dopaminergic medication