The Effects Of Dopaminergic Medication On Decision-making Under Ambiguity In Patients With Parkinson's Disease

Objective Dopamine in the brain is to participate the regulation of cognitive function in the prefrontal cortex,the reduction of dopamine leads to prefrontal-striatal loop dysfunction,thus affecting the cognitive function of PD patients.Decision-making is a comprehensive measure of the available options and making the optimal choice which is a complex psychological process that is influenced by multiple cognitive and behavioral processes.The damage of decision-making capacity can have a serious impact on PD patients' ability to work,social interaction and family life.The decision-making function is also related to the prefrontal-striatal loop and the limbic system.At present,dopaminergic drugs are the golden standard therapy for motor symptoms in PD patients,but there are few studies on the impact of decision-making function in PD patients.Therefore,the aim of this study was to investigate the effect of dopaminergic drugs on the decision-making ability of Parkinson's disease patients.Method Using Iowa Gambling Task(IGT)for 28 non-medication idiopathic PD patients,28 idiopathic PD patients with regular dopaminergic medication and also for 28 healthy controls(HC)whose age,gender,education matche to PD patients to test their ability of decision-making under ambiguity.Results The results showed non-medication PD group impaired on digtal span and verbal fluency and decision-making task.There was significant difference in IGT task scores among the three groups().The total net scores of advantageous choices in IGT were significantly lower in non-medication PD group(-4.5 ± 22.19)than medication PD group(8.83 ± 23.24)and healthy group(15.92±15.77).The difference of net scores in block1 to block5 between non-medication PD group and medication PD group was gradually increased,the difference of net scores in block4 and block5 was significant(P<0.05).There was no significant difference in total net scores and net scores in block1 to block5 between medication PD group and healthy group(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.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.But the ability of decision-making under ambiguity of medication PD group does not impair.