title: Investigating the effects of caffeine on phonation.
abstract: OBJECTIVE
  A core component of vocal hygiene programs is the avoidance of agents that may dry the vocal folds. Clinicians commonly recommend that individuals reduce caffeine intake because of its presumed dehydrating effects on the voice. However, there is little evidence that ingestion of caffeine is detrimental to voice production. The first objective of this study was to evaluate whether caffeine adversely affects voice production. The second objective was to evaluate if caffeine exacerbates the adverse phonatory effects of vocal loading.
  
  
  METHODS
  Prospective, double-blinded, sham-controlled study.
  
  
  METHODS
  Sixteen healthy adults participated in two sessions where they consumed caffeine (caffeine concentration=480 mg) or sham (caffeine concentration=24 mg) beverages. Voice measures (phonation threshold pressure and perceived phonatory effort) were collected. Subjects then completed a vocal loading challenge and voice measures were obtained again.
  
  
  RESULTS
  There were no significant differences in voice measures between the caffeine and sham conditions. Ingestion of caffeine did not adversely affect voice production (P>0.05) or exacerbate the detrimental phonatory effects of vocal loading (P>0.05).
  
  
  CONCLUSIONS
  Our findings contribute to emerging knowledge on the effects of caffeine on voice production. Recommendations to completely eliminate caffeine from the diet, as a component of a vocal hygiene program, should be evaluated on an individual basis.
authors.affiliation: Department of Speech, Language and Hearing Sciences, Purdue University, West Lafayette, Indiana 47907, USA.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Erickson-Levendoski
authors.forename: Mahalakshmi
authors.initials: M
authors.lastname: Sivasankar
mesh_terms: D000293:Adolescent; D000328:Adult; D001628:Beverages; D002110:Caffeine / Q000008:administration & dosage* / Q000009:adverse effects; D000697:Central Nervous System Stimulants / Q000008:administration & dosage* / Q000009:adverse effects; D003681:Dehydration / Q000139:chemically induced; D005260:Female; D006801:Humans; D008297:Male; D010699:Phonation / Q000187:drug effects*; D011446:Prospective Studies; D014827:Vocal Cords / Q000187:drug effects*; D055815:Young Adult
chemical_list: D000697:Central Nervous System Stimulants; D002110:Caffeine