Introduction: The cognitive disorders presented by patients with Parkinson s disease (PD) have drawn attention to the role played by the basal ganglia in cognition. It has been suggested that through a system of cortico subcortical circuits they monitor the work done by the frontal regions by guiding the anterior and posterior attentional systems, whose functioning is necessary for the so called executive functions to be carried out.
Patients and methods: We studied 10 patients with PD in developmental stages I and II according to the scale of Hoehn and Yahr, and 10 healthy paired controls. All of them were administered a test for simple sustained attention, complex sustained attention and attentional shift.
Results: In the simple sustained attention task there were no significant differences between groups. In the complex sustained attention test the patients committed more mistakes, and in the attentional shift task they committed more omissions and there was a significant increase in reaction time.
Conclusions: Even in the early stages of the disease, patients suffering from Parkinson present cognitive disorders. These are concentrated in the detection and evaluation of new information, in the capability to shift attention between different spatial regions in a flexible manner and in choosing, inhibiting and activating motor programmes. In order to detect these alterations more sensitive and complex tests must be used.