Decision making in de novo Parkinson's disease.

The aim is to study decision making in patients with de novo Parkinson's disease (PD). Recent studies reported that medicated patients with PD have poor performances compared with age-matched healthy controls in decision making tasks, specially in the Iowa Gambling Task. Two principal causal hypotheses have been proposed to explain this phenomenon: the overdosing effects of dopaminergic therapy on the orbital frontostriatal circuit that is involved in reward processing, or an amygdala dysfunction, as suggested by similar Skin Conductance Responses of patients with PD and amygdala-damaged patients while performing this task. The assessment of decision making with the Iowa Gambling Task was conducted in 30 nondemented and nondepressed patients with de novo PD and in 25 age-matched healthy controls. No statistically significant difference emerged between performances of de novo PD patients and performances of healthy controls. De novo PD patients have performances in the Iowa Gambling Task similar to those of age-matched healthy controls, suggesting that difficulties in decision making emerge, at least in de novo PD patients, by dopaminergic overstimulation of the orbital frontostriatal circuits.