Decision-making Under Ambiguity In Early Parkinson’s Disease

Backgroud A variety of cognitive functions are impaired in patients with Parkinson’sdisease (PD). Decision-making, as a part of the cognitive function, has an importantimpact on daily behavior. Although the decision making function has been reported tobe damaged in PD patients, however, whether the decision making function underambiguity are affected in early stage of this disorder was not decided and the relativemechanism is poorly understood.Objective To investigate the ability of decision making under ambiguity condition inearly Parkinson’s disease, explore the relation of this deficiency with other cognitivefunction and damage in basal ganglia.Methods Twenty patients with early Parkinson’s disease, twenty patients with rightbasal ganglia infarction (BGI) and twenty health controls from the First AffiliatedHospital of Anhui Medical University matched for age and sex were selected as objectsof study. The ability of decision-making under ambiguity were analyzed with IowaGambling Task(IGT) in all subjects. The general cognitive functions in subjects wereassessed with Montreal Cognitive Assessment (MoCA), Digital Span (DS), HamiltonDepression Rating Scale(HAMD) and Stroop test. Unified Parkinson’s Disease RatingScale Part Ⅲ(UPDRS Ⅲ) and Hohen-Yahr stage rating scale(H-Y) were used inpatients with PD to assess the stage of the disease. χ2test, analysis of variance (ANOA),LSD and linear regression were used for statistical analysis. Results1. There are no significant differences in gender, age, years of education and otherdemographic data in the three groups (P>0.05). In the general cognitive tests, thescore of the HAMD assessment is significantly higher(F=6.19,P<0.05) in BGIgroup (4.20±1.01) than early PD group (3.25±1.33) and HC group (2.80±1.47),score of the Stroop test is markedly higher(F=33.27,P<0.05) in the early PDgroup (21.35±4.28) compared with BGI group (13.30±3.21) or HC group(13.60±2.98).2. The early PD group (48.95±7.01) selected less advantageous choices than BGIgroup (52.95±2.72) and HC group (53.15±2.43) in term of the total IGTscore(F=5.38,P<0.05). More specifically, the poor performance for early PD groupis mainly displayed in the last two stages (60-80,80-100) when the scores of theeach stage in the IGT are analyzed separately (P<0.05). No difference was foundbetween BGI group and HC group in term of total advantage choices or any stagescores of IGT (P>0.05).3. The frequency of the advantageous options choosing in early PD group is correlatedwith the results of Stroop test（r=-0.65，P<0.05）,but not with age, education leveland the scores of MoCA, DS, HAMD, UPDRS III and H-Y (P>0.05).Conclusion1. Patients with Parkinson’s disease, even in the early stage, may have impairments indecision-making function under ambiguity.2. Patients with unilateral basal ganglia ischemic damage show normaldecision-making ability under ambiguity as well as normal executive function.Malfunction of decision-making under ambiguity in early PD may be associated with damage inbrain areas other than basal ganglia.3. Malfunction of decision-making under ambiguity in early PD patients is correlated with results of Stroop test, but not with general cognitive function(MoCA),attention(DS),motor dysfunction(UPDRS III) and disease stage (H-Y),indicatingdecision-making dysfunction may be related to impairment of front lobe associatedexecutive function in patients with early Parkinson’s disease.