Selective attention deficits in early and moderate stage Parkinson's disease.

Patients with Parkinson's disease (PD) often show impaired performance on visuospatial attentional tasks. The objective of the study was to examine the attentional function of PD patients performing the attentional network test (ANT). We used the ANT to compare PD patients with healthy controls with respect to the efficiency of 3 anatomically defined attentional networks: the alerting, orienting, and executive control networks. We found that PD patients showed a selective abnormality in the orienting network. Although the alerting and executive control networks apparently remained unaffected, the efficiencies of these networks in patients with PD negatively correlated with the Hoehn-Yahr stage. The results supported the idea that the orienting processes may be more dynamic in PD than in non-PD individuals.