New Study Shows That People with Early PD are Less Sensitive Than Others to Rewarding Events

What are th early signs of PD? many scientists have speculated that early PD may be characterized by a loss of sensitivity to certain rewards or pleasurable events because dopamine is important to processing 'reward' and pleasure. Scientists recently tested that idea in people with early PD before they were medicated with drugs that enhance dopamine and AFter they were treated with dopamine. They found that never-medicated patients with Parkinson's disease showed selective deficits on reward processing and that these deficits were eliminated after treatment with dopamine drugs. However for some persons with PD other abnormalities of reward processing emerged after treatment. Patients treated with the dopamine agonists showed signs of abnormal 'punishment processing'. they in effect paid too much heed to rewarding aspects of an event and no heed to punishing or harmful aspects of a situation. These findings can help us identify people at risk for PD (those insensitive to reward) and those persons with PD who are at risk for 'impulse control disorders' like gambling and sexual improprieties. These would be the patients on dopamine agonists who give too much weight to rewarding events and not enough weight to potentially harmful events.

Source: Reward-learning and the novelty-seeking personality: a between- and within-subjects study of the effects of dopamine agonists on young Parkinson's patients Brain Advance Access published on May 4, 2009.