Disturbed striatoprefrontal mediated visual behaviour in moderate to severe parkinsonian patients
- Professor L Crevits, Department of Neurology, Neuro-Ophthalmology Unit, University Hospital, De Pintelaan 185, B-9000 Gent, Belgium.
- Received 16 July 1996
- Revised 28 February 1997
- Accepted 8 April 1997
OBJECTIVES To study visuospatial and visual memory functions in moderate to severe parkinsonian patients.
METHODS Visual antisaccades (AS) and remembered saccades (RS) were examined in 30 patients with moderate to severe Parkinson’s disease and in 44 age matched controls. AS are saccades in the direction opposite to the target. RS are saccades towards the remembered position of a target that is no longer visible.
RESULTS Patients with Parkinson’s disease had serious difficulties in suppressing a reflex saccade (“visual grasping”) or they made no saccade at all (“visual akinesia”). The remembered saccade was often wrongly directed.
CONCLUSIONS These types of errors point to a dysfunction in the striatoprefrontal loop. The discrepancy of the results with those in the literature, which are mostly normal, could be explained by the more advanced stage of our patients. This might correspond to the development of unresponsiveness to levodopa or of non-dopaminergic lesions.