Study Description:

We will investigate the relationship between Dopamine (DA) function and attention in patients with asymmetric Parkinson Disease (PD). We hypothesize that the direction of asymmetry in dopamine (DA) depletion predicts the asymmetry in visual attention.

Primary Objective:

• to study attentional asymmetry in patients with PD. We hypothesize that visual attention in Parkinson will be biased to the visual field contralateral to the least affected hemisphere (i.e. contralateral to the most affected side).

Secondary Objectives:

• to investigate the correlation between feedback learning and visuospatial attention performance in PD. We hypothesize that feedback learning will also be affected according to the most compromised hemisphere. Right hemisphere-predominant PD patients (left-motor predominant), compared to left hemisphere-predominant patients, will exhibit a rightward visuospatial bias and a relative preference for learning from reward, compared to punishment.
• to investigate the effect of prism adaptation on feedback learning and visuospatial attention in PD. This objective is exploratory. Endpoints

Primary Endpoint: visuospatial performance on the Landmark Task

Secondary Endpoints: performance on:

• Posner Task
• Visual Search Task
• Attentional blink Task
• Visuospatial performance on the Manual Line Bisection Task
• Reward and Punishment Implicit Feedback Learning Task
• The Attentional Scaling Task

Functional connectivity measured with resting state fMRI.

Study Population:

Sixty patients with asymmetric PD. Any gender, aged 35-80 (inclusive), able to give consent and without a diagnosis of significant illness affecting the central nervous system other than PD.