Levodopa slows prosaccades and improves antisaccades: an eye movement study in Parkinson’s disease
- Ashley J Hood1,
- Silvia C Amador1,
- Ashley E Cain1,
- Kevin A Briand1,
- Ali H Al-Refai2,
- Mya C Schiess3,
- Anne B Sereno1
- 1Department of Neurobiology and Anatomy at the University of Texas Medical School, Houston, Texas, USA
- 2Department of Neuroscience, Jordan University of Science and Technology, Irbid, Jordan
- 3Department of Neurology at the University of Texas Medical School, Houston, Texas, USA
- Correspondence to: Ashley J Hood Department of Neurobiology and Anatomy, 6431 Fannin Street, MSB 7.526, Houston, TX, 77030, USA; ashley.jagar{at}uth.tmc.edu
- Received 14 June 2006
- Accepted 30 November 2006
- Revised 18 November 2006
- Published Online First 18 December 2006
Abstract
Background: The integrity of frontal systems responsible for voluntary control and their interaction with subcortical regions involved in reflexive responses were studied in patients with Parkinson’s disease (PD). Previous studies have shown that patients with PD have impaired executive function, including deficits in attention, motor planning and decision making.
Methods: Executive function was measured through eye movements: reflexive (stimulus driven) prosaccades and voluntary (internally guided) antisaccades. Patients with advanced idiopathic PD, off and on their optimal levodopa therapy, were tested on a prosaccade and an antisaccade task and compared with matched controls.
Results: Levodopa significantly increased response time for reflexive prosaccades and reduced error rate for voluntary antisaccades.
Conclusions: Consistent with our proposed model, patients with PD in the medicated state are better able to plan and execute voluntary eye movements. These findings suggest levodopa improves function of the voluntary frontostriatal system, which is deficient in PD.
Footnotes
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Published online first 18 December 2006
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Competing interests: None.







