title: Delay of simple reaction time after levodopa intake.
abstract: BACKGROUND
  Parkinsonian patients (PP) have deficits in the preparation and execution of movements. It is generally accepted that PP show delayed performance of simple reaction time (SRT) paradigms due to impaired response preprogramming. To date, no trial considered putative effects of dopaminergic substitution on SRT performance in PP.
  
  
  OBJECTIVE
  To determine short-term effects of acute levodopa intake and impact of long-term dopaminergic substitution on the results of a SRT task.
  
  
  METHODS
  We repeatedly performed a SRT paradigm in previously untreated- and treated PP, taken off medication for at least 12 h, before and after intake of levodopa/benserazide and in PP, who received placebo.
  
  
  RESULTS
  Reaction time significantly increased and movement time did not change after levodopa intake. Placebo application showed no effects.
  
  
  CONCLUSIONS
  Levodopa delayed cognitive processing and/or behaviour. Sedative effects of levodopa and/or dopamine overflow in prefrontal regions with subsequent cholinergic dysfunction hypothetically caused this phenomenon.
authors.affiliation: Department of Neurology, St. Josef Hospital, Ruhr University Bochum, Gudrunstrasse 56, 44791, Bochum, Germany. thomas.mueller@ruhr-uni-bochum.de
authors.forename: T
authors.initials: T
authors.lastname: Müller
authors.forename: S
authors.initials: S
authors.lastname: Benz
authors.forename: C
authors.initials: C
authors.lastname: Börnke
mesh_terms: D000328:Adult; D000368:Aged; D000978:Antiparkinson Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D001519:Behavior / Q000187:drug effects; D001545:Benserazide / Q000008:administration & dosage / Q000627:therapeutic use; D003071:Cognition / Q000187:drug effects; D015259:Dopamine Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D004338:Drug Combinations; D005260:Female; D006801:Humans; D007980:Levodopa / Q000008:administration & dosage / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000187:drug effects; D010300:Parkinson Disease / Q000188:drug therapy* / Q000503:physiopathology* / Q000523:psychology; D011569:Psychiatric Status Rating Scales; D011930:Reaction Time / Q000187:drug effects; D012016:Reference Values
chemical_list: D000978:Antiparkinson Agents; D015259:Dopamine Agents; D004338:Drug Combinations; D007980:Levodopa; D001545:Benserazide