Abnormalities of smooth eye and head movement control in Parkinson's disease

• Published in: Annals of neurology Vol. 39; no. 6; p. 749
• Main Authors: Waterston, J A, Barnes, G R, Grealy, M A, Collins, S
• Format: Journal Article
• Language: English
• Published: United States 01.06.1996
• Subjects: Adult; Aged; Female; Head - physiopathology; Humans; Levodopa - pharmacology; Levodopa - therapeutic use; Male; Middle Aged; Movement - drug effects; Parkinson Disease - drug therapy; Parkinson Disease - physiopathology; Pursuit, Smooth - drug effects; Reaction Time; Reflex, Vestibulo-Ocular - drug effects; Saccades - drug effects
• ISSN: 0364-5134
• DOI: 10.1002/ana.410390611

The control of horizontal head and eye movements was examined in 13 nondemented patients with Parkinson's disease (PD) of mild to moderate severity. During pursuit of single-frequency sine waves, smooth component eye velocity was lower in the PD group at frequencies of 1.2 Hz and above; but the differences in overall eye displacement were even greater, indicating an impaired ability to generate catch-up saccades at high frequencies. A corresponding deficit in saccadic performance was observed during a high-frequency saccadic tracking task where predictive saccades of reduced gain and variable timing were generated. During pursuit of pseudo-random target motion with varying degrees of predictability, small differences in smooth component eye velocity were observed, but prediction was otherwise well preserved in the patient group. Vestibulo-ocular reflex (VOR) suppression was also normal during head-free pursuit. No major improvement in smooth pursuit gain could be attributed to drug treatment, based on a comparison of patient results before and after administration of levodopa.