Levodopa slows prosaccades and improves antisaccades: an eye movement study in Parkinson's disease.
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.
Hood
Ashley J
AJ
Department of Neurobiology and Anatomy, University of Texas Medical School, Houston, TX 77030, USA. ashley.jagar@uth.tmc.edu
Amador
Silvia C
SC
Cain
Ashley E
AE
Briand
Kevin A
KA
Al-Refai
Ali H
AH
Schiess
Mya C
MC
Sereno
Anne B
AB
D000368:Aged; D000978:Antiparkinson Agents / Q000494:pharmacology / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007980:Levodopa / Q000494:pharmacology / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D015835:Ocular Motility Disorders / Q000188:drug therapy* / Q000209:etiology; D010300:Parkinson Disease / Q000150:complications* / Q000188:drug therapy; D011597:Psychomotor Performance / Q000187:drug effects; D011930:Reaction Time / Q000187:drug effects; D012438:Saccades / Q000187:drug effects* / Q000502:physiology
D000978:Antiparkinson Agents; D007980:Levodopa