The Neuropsychological Study On Decision-making Under Risk Condition In Patients With Basal Ganglia Lesion

Objective Life demands that we make innumerable decisions on a daily basis.Impaired decision-making would cause a lot of unnecessary troubles in daily life.Normal decision-making is thought to require an extended neural network, mainlycomprising the frontostriatal and limbic loops. Basal ganglia plays a crucial role indecision-making. The aim of this paper is to investigate the ability of decision makingunder risk condition in patients with Parkinson’s Disease (PD) and Wilson’s Disease(WD), and to further explore the neural relationship between basal ganglia and theability of decision-making．Method The Game of Dice Task (GDT) is a commonly used measure of decisionmaking with risk. Experiment1:25PD patients, healthy controls (HC1) are investigatedby Game of Dice Test (GDT) with explicit probability. Experiment2:30WD patientsand healthy controls (HC2) are investigated by Game of Dice Test (GDT) with explicitprobability.Result In experiment1, PD patients performed poorly in the entire task, selected morerisky options (PD：10.88±5.58, HC1：5.72±3.69, t=3.86, P<0.01), compared withhealthy controls. In general, the final capital of PD group was negative while the resultof HC group was always profitable and the discrepancy was significant (PD：-3748.00±3923.87, HC1：684.00±1764.62, t=-5.15, P<0.01). The most frequent choice madeby PD patients was one number, which is the most risky one. Accordingly, the mostfrequent choice made by HC group was three numbers (one number: PD：6.48±5.81,HC1：1.00±1.44, t=4.58, P<0.01; three numbers: PD：2.64±2.14, HC1：7.04±2.54, t=-6.62, P<0.01), but mean frequency of2numbers (PD：4.40±4.10, HC：4.72±2.99,t=－0.32, P=0.76) and4numbers (PD：4.48±5.04, HC：5.24±3.72, t=－0.61, P=0.55) did not reach significance. The net scores of HC1continually increased during3blocks of the task, but those of the PD group did not (Block1: PD：-2.80±3.58,HC1：0.7±3.20, t=-3.26, P=0.002; Block2: PD：-1.70±4.01, HC1：2.70±2.70, t=-4.07, P<0.001; Block3: PD：-2.40±4.13, HC1：2.90±2.47, t=-4.92, P<0.001).Compared to HC1, PD patients used less negative feedback (PD：0.27±0.29, HC：0.76±0.26, t=-5.41, P<0.01). The frequency of choosing the risky options hadcorrelation with the rate of using negative feedback (r=-0.59, P=0.003), and the resultof Stroop test (r=0.55, P=0.004).In experiment2, WD patients showed greater preference than HC2did fordisadvantageous choices (WD：9.87±5.95, HC2：5.00±3.35, t=3.91, P <0.001). Thefinal capital of the WD patients was also significantly lower than that of HC2(WD：-2093.33±3635.83, HC2：516.67±1595.70, t=–3.60, P=0.001). The most frequentchoice made by WD patients was two numbers, which is the more risky. Accordingly,the most frequent choice made by HC2group was three numbers. Single comparisonsbetween the groups revealed significant differences in the frequency for choosing asingle number (one number: WD：4.33±4.64, HC2：0.90±1.40, t=3.88, P <0.001) and3numbers (three numbers: WD：3.43±3.34, HC2：7.47±2.85, t=–5.03, P <0.001),but mean frequency of2numbers (WD：5.50±4.58, HC2：4.10±2.78, t=1.41, P=0.16) and4numbers (WD：4.73±5.24, HC2：5.50±3.52, t=–0.67, P=0.51) did notreach significance. The net scores of HC2continually increased during3blocks of thetask, but those of the WD group did not (Block1: WD：-1.00±4.86, HC2：1.53±3.14, t=-2.40, P=0.02; Block2: WD：-0.40±4.47, HC2：3.20±2.20, t=-3.96, P<0.001; Block3: WD：-0.47±4.63, HC2：3.33±2.43, t=-3.98, P<0.001). Comparedto HC2, WD patients used less negative feedback (WD：0.34±0.31, HC2：0.78±0.23, t=–0.97, P <0.001). In the WD group, the frequency of disadvantageous options was highly negatively correlated with the final capital (r=0.60, P <0.001) and theutilization of negative feedback (r=－0.59, P=0.003）. It has also correlated withWisconsin Card Sorting Test scores (categories completed: r=–0.784, P=0.002,preservative errors: r=0.718, P=0.006).Conclusion Present study has shown that patients with PD and WD have significantimpairments in decision-making under risk condition, and has correlation withexecutive function and negative feedback. The basal ganglia play a crucial role indecision-making under risk, by the processes of executive function and feedback.