Visuospatial deficits in Parkinson's disease assessed by judgment of line orientation test: Error analyses and practice effects

The Benton's Judgment of Line Orientation (JLO) is one of the tests most fr equently used to assess visuospatial function. The aim of the present study was to analyze qualitative errors in Parkinson's disease (PD) following th e method described by Ska, Poissant, and Joanette (1990) and to determine p ossible practice effects of this test. The JLO was administered to 76 idiop athic PD patients and 76 matched normal controls. The analyses of errors sh owed several qualitative differences between groups, Parkinson's patients m ade a greater proportion of complex intraquadrant errors and horizontal lin e errors, while they showed fewer simple intraquadrant errors than controls . The JLO test was also administered twice in an interval of 20min in a sub sample of 25 PD patients and 25 normal controls. The results did not show s ignificant differences between the two administrations, indicating that the test is free of practice effects. In conclusion, these data provide furthe r evidence for the existence of visuospatial deficits in PD. Moreover, the JLO has proved to be an appropriate test for the assessment of the visuospa tial function in patients who require a neuropsychological follow up.