title: Effect of Levodopa + Carbidopa on the Laryngeal Electromyographic Pattern in Parkinson Disease.
abstract: BACKGROUND
  Vocal impairment is one of the main debilitating symptoms of Parkinson disease (PD). The effect of levodopa on vocal function remains unclear.
  
  
  OBJECTIVE
  This study aimed to determine the effect of levodopa on electromyographic patterns of the laryngeal muscle in patients with PD.
  
  
  METHODS
  This is a prospective interventional trial.
  
  
  METHODS
  Nineteen patients with PD-diagnosed by laryngeal electromyography-were enrolled. Cricothyroid and thyroarytenoid (TA) muscle activities were measured at rest and during muscle contraction (phonation), when participants were on and off medication (12 hours after the last levodopa dose).
  
  
  RESULTS
  Prevalence of resting hypertonia in the cricothyroid muscle was similar in the off and on states (7 of 19, P = 1.00). Eight patients off medication and four patients on medication had hypertonic TA muscle at rest (P = 0.289). No electromyographic alterations were observed during phonation for either medication states.
  
  
  CONCLUSIONS
  Despite a tendency for increased rest tracings in the TA muscle when participants were on medication, no association was found between laryngeal electromyography findings and levodopa + carbidopa administration.
authors.affiliation: Department of Otolaryngology, Medical Science Faculty of Santa Casa de São Paulo Hospital, São Paulo, São Paulo, Brazil.
authors.forename: Gustavo
authors.initials: G
authors.lastname: Noffs
authors.affiliation: Department of Otolaryngology, Medical Science Faculty of Santa Casa de São Paulo Hospital, São Paulo, São Paulo, Brazil. Electronic address: adcduprat@gmail.com.
authors.forename: André
authors.initials: A
authors.lastname: de Campos Duprat
authors.affiliation: Laryngeal Electromyography Department, Sírio Libanês Hospital, São Paulo, São Paulo, Brazil.
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: Zarzur
authors.affiliation: Department of Neurology, Division of Functional Neurosurgery, University of São Paulo School of Medicine, São Paulo, São Paulo, Brazil.
authors.forename: Rubens Gisbert
authors.initials: RG
authors.lastname: Cury
authors.affiliation: Department of Neurology, Medical Science Faculty of Santa Casa de São Paulo Hospital, São Paulo, São Paulo, Brazil.
authors.forename: Berenice Oliveira
authors.initials: BO
authors.lastname: Cataldo
authors.affiliation: Department of Neurology, Division of Functional Neurosurgery, University of São Paulo School of Medicine, São Paulo, São Paulo, Brazil.
authors.forename: Erich
authors.initials: E
authors.lastname: Fonoff
mesh_terms: D000368:Aged; D000978:Antiparkinson Agents / Q000008:administration & dosage* / Q000009:adverse effects; D001938:Brazil; D002230:Carbidopa / Q000008:administration & dosage* / Q000009:adverse effects; D004334:Drug Administration Schedule; D004338:Drug Combinations; D004576:Electromyography; D005260:Female; D006801:Humans; D007821:Laryngeal Muscles / Q000187:drug effects* / Q000503:physiopathology; D007980:Levodopa / Q000008:administration & dosage* / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000175:diagnosis / Q000188:drug therapy* / Q000503:physiopathology; D010699:Phonation / Q000187:drug effects*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D013997:Time Factors; D016896:Treatment Outcome; D014833:Voice Quality / Q000187:drug effects*
chemical_list: D000978:Antiparkinson Agents; D004338:Drug Combinations; C009265:carbidopa, levodopa drug combination; D007980:Levodopa; D002230:Carbidopa
keywords: Electromyography; Laryngeal muscle; Levodopa; Parkinson disease; Voice