title: Tapping and peg insertion after levodopa intake in treated and de novo parkinsonian patients.
abstract: BACKGROUND
  Investigators use instrumental tasks for objective assessment of parkinsonian motor disability and its drug response. To date, such studies on treated parkinsonian patients have not addressed acute and long-term effects of dopaminergic drugs.
  
  
  OBJECTIVE
  To determine the impact of long-term dopaminergic therapy within a standardized levodopa challenge test design in combination with two repeatedly performed instrumental tasks, peg insertion and tapping, in previously treated and untreated parkinsonian patients.
  
  
  RESULTS
  Tapping significantly deteriorated in previously untreated, but not in treated parkinsonian patients after levodopa intake. In contrast, motor symptoms and peg insertion significantly improved in both groups of parkinsonian patients. Results of both tests differed between parkinsonian patients and matched controls.
  
  
  CONCLUSIONS
  Worsening of cognitively less demanding tapping may result from upregulated presynaptic inhibitory feedback regulation, sedative effects of levodopa or dopamine overflow in untreated parkinsonian patients, who are sensitive to these effects in contrast to treated parkinsonian patients. Tapping is a task with autonomic repetitive performance and programming of standardised movements with a low need for cognitive effort. This autonomic functioning of attentional control and selective processing is intact in Parkinson's disease. Peg insertion depends on more complex movements and thus hypothetically on dopamine-associated cognitive processes. Therefore, impairment of peg insertion responded to dopaminergic stimulation in both groups of parkinsonian patients. Future studies on the efficacy of antiparkinsonian drugs, using instrumental tasks for objective assessment, should consider long-term impact of antiparkinsonian drug therapy and associated cognitive efforts.
authors.affiliation: Department of Neurology, St Josef Hospital, Ruhr University Bochum, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Muller
authors.forename: Sabiene
authors.initials: S
authors.lastname: Benz
authors.forename: Horst
authors.initials: H
authors.lastname: Przuntek
mesh_terms: D000328:Adult; D000368:Aged; D000978:Antiparkinson Agents / Q000008:administration & dosage; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007980:Levodopa / Q000008:administration & dosage; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000188:drug therapy* / Q000503:physiopathology*; D011597:Psychomotor Performance / Q000187:drug effects*; D013997:Time Factors
chemical_list: D000978:Antiparkinson Agents; D007980:Levodopa