Abstract

Backgrounds and aims: Visual misperceptions due to dopamine depletion could take place at an early stage of the Parkinson’s Disease (PD). However, there is evidence in literature of inconsistent results about visual attention skills of parkinsonian patients undergoing medical treatment. Some authors found some difficulties in PD engaged in a visual attention task of salient stimuli with distributed attention, while it is similar when they have to search for targets among distractors (with feature conjunctions). Other authors, however, do not find evidence of impairments in the visual attention task. We will try to clarify some of these aspects with the results of our research.
Method: We conducted a preliminary experiment to assess whether patients could have a better performance in a “Pop Out” visual search when set in a “Top Down” mode. We then conducted Study 1, in which we administered a cancellation test that separates the motor from the visual attention component. In Study 2, participants performed the Navon test (1977) in order to investigate visual attention style.
Result: Results show that patients with PD have hesitations in the cancellation test mainly due to the motor impairment, not in the serial visual attention. In the Navon task, we reported a narrow and closed focusing style.
Discussion:Let’s assume that these effects could be due either to the low contrast sensitivity in their retinal periphery, or to the excessive protective function of peripheral attentional filters that try to compensate the deteriorated central filters, partly located in basal ganglia. Further investigations will need to follow.

Keywords:Parkinson; Visual attention; Cancellation test; Navon test