Covert orientation of visual attention in Parkinson's disease: an impairment in the maintenance of attention.

Covert orientation of attention was studied in a group of patients with idiopathic Parkinson's disease and compared to a matched control group using a cued reaction time task which measured disengagement, covert movement and engagement of attention. Parkinson patients had an increased response latency and disengaged from attended locations more readily than controls. This impairment in the maintenance of attention in Parkinson's disease was comparable to that produced in a previous study by pharmacological blockade of brain catecholamines in normal subjects. It is suggested that an impairment in the maintenance of oriented attention may underlie some of the cognitive deficits reported in Parkinson's disease.