OBJECT-BASED AND LOCATION-BASED SHIFTING OF ATTENTION IN PARKINSONS-DISEASE

Research into Parkinson's disease has made much use of the precuing pa radigm developed by Posner to examine patients' ability to shift visuo spatial attention. The majority of studies indicate that patients with Parkinson's disease have significantly reduced shift costs when compa red with normal controls. This reduction in costs is ascribed to abnor mal maintenance of attention resulting from Parkinson's disease. We kn ow that visual attention is not directed to spatial locations alone bu t that it map also be directed to object representations. To date, how ever, it has nor been clear whether the reduced shift costs apparent i n Parkinson's disease patients are evident only on spatial locations o r on both spatial locations and object representations. Therefore, in the current study we have adopted a new technique with a view to study ing both location-based and object-based attentional components within the same paradigm. Our results with 17 patients with Parkinson's dise ase suggest, at least in the early stages, patients do nor show defici ts in maintenance of attention to the miscued source of stimulation as reflected in their normal magnitude of cuing effect related to shifti ng between locations and between objects. 14 normal persons were contr ol subjects.