title: Can expectations produce symptoms from infrasound associated with wind turbines?
abstract: OBJECTIVE
  The development of new wind farms in many parts of the world has been thwarted by public concern that subaudible sound (infrasound) generated by wind turbines causes adverse health effects. Although the scientific evidence does not support a direct pathophysiological link between infrasound and health complaints, there is a body of lay information suggesting a link between infrasound exposure and health effects. This study tested the potential for such information to create symptom expectations, thereby providing a possible pathway for symptom reporting.
  
  
  METHODS
  A sham-controlled double-blind provocation study, in which participants were exposed to 10 min of infrasound and 10 min of sham infrasound, was conducted. Fifty-four participants were randomized to high- or low-expectancy groups and presented audiovisual information, integrating material from the Internet, designed to invoke either high or low expectations that exposure to infrasound causes specified symptoms.
  
  
  RESULTS
  High-expectancy participants reported significant increases, from preexposure assessment, in the number and intensity of symptoms experienced during exposure to both infrasound and sham infrasound. There were no symptomatic changes in the low-expectancy group.
  
  
  CONCLUSIONS
  Healthy volunteers, when given information about the expected physiological effect of infrasound, reported symptoms that aligned with that information, during exposure to both infrasound and sham infrasound. Symptom expectations were created by viewing information readily available on the Internet, indicating the potential for symptom expectations to be created outside of the laboratory, in real world settings. Results suggest psychological expectations could explain the link between wind turbine exposure and health complaints.
authors.affiliation: Department of Psychological Medicine, University of Auckland.
authors.forename: Fiona
authors.initials: F
authors.lastname: Crichton
authors.affiliation: Acoustic Research Centre, University of Auckland.
authors.forename: George
authors.initials: G
authors.lastname: Dodd
authors.affiliation: Acoustic Research Centre, University of Auckland.
authors.forename: Gian
authors.initials: G
authors.lastname: Schmid
authors.affiliation: Department of Medicine, University of Auckland.
authors.forename: Greg
authors.initials: G
authors.lastname: Gamble
authors.affiliation: Department of Psychological Medicine, University of Auckland.
authors.forename: Keith J
authors.initials: KJ
authors.lastname: Petrie
mesh_terms: D001294:Attitude to Health; D001309:Auditory Threshold; D004311:Double-Blind Method; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D009622:Noise / Q000009:adverse effects*; D011210:Power Plants; D014919:Wind