Objective: To evaluate the effects of sensory reward cues on risky decision making in unmedicated and medicated Parkinson’s disease (PD).

Background: Cue reactivity may play an important role in impulsive-compulsive behaviours resulting from dopaminergic therapy. Patients with such behaviours show increased dopamine release in response to reward cues in the medicated state. However, it is unclear what effects reward cues have on behaviour in PD patients and how these effects might be modulated by medication. Recent animal and human data suggest that salient audio-visual reward cues can promote risk taking, and according to the animal data, this risk-promoting effect is dopamine-dependent. Here, we aimed to examine whether similar risk-promoting effects would be seen in PD patients and how they may be modulated by dopaminergic therapy.

Methods: 23 patients with idiopathic Parkinson’s disease (10 on levodopa monotherapy and 13 on both levodopa and dopamine agonists) without impulsive-compulsive behaviours performed two versions of a risky decision making task previously validated in healthy volunteers. In one version of the task, rewards were accompanied by images of money and casino jingles; in the other version, rewards were unaccompanied by reward cues. Patients performed both task versions ON and OFF their usual medication, in a randomized order.

Results: Sensory reward cues interacted significantly with the medication state (p = .01). In the unmedicated state, the PD patients showed increased risk taking when rewards were accompanied by the cues (p <.0005). However, sensory reward cues did not promote risk in the medicated state.

Conclusions: Decision making of PD patients without impulsive-compulsive behaviours is susceptible to risk-promoting effects of reward cues, but only in the unmedicated state. Dopaminergic therapy may eliminate this effect by disrupting the endogenous patterns of phasic dopamine signaling in response to salient rewarding stimuli. It remains to be seen how these effects may be altered in patients with impulsive-compulsive behaviours.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/the-effects-of-sensory-reward-cues-on-risky-decision-making-in-parkinsons-disease/