Assessment of visual-spatial deficits in patients with Parkinson's disease and closed head injuries using virtual environments.

Cognitive spatial deficits have been reliably reported in patients with Closed Head Injury (CHI), though in patients with Parkinson's disease (PD) the phenomenon is disputed. CHI and non-demented PD patients were tested using a Judgement of Line Orientation Test, and two spatial tests using virtual environments (VEs). Performance on the Line Orientation and one VE test was worse in the CHI group than controls, but PD patients showed no apparent spatial deficits. However, performance on the second VE test (virtual tray of objects task) did reveal a deficit, both CHI and PD groups being significantly impaired. The data illustrate that particular spatial deficits can be differentiated using appropriate VE-based tasks, and that non-demented PD patients show a paradigm-specific visual-spatial impairment.