Can Expectations Produce Symptoms From Infrasound Associated With Wind Turbines?
Crichton F, Dodd G, Schmid G, Gamble G, Petrie KJ.
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.Method: 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
pre-exposure 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. (PsycINFO Database Record (c) 2013 APA, all rights reserved).
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Are media warnings about the adverse health effects of modern life self-fulfilling? An experimental study on idiopathic environmental intolerance attributed to electromagnetic fields (IEI-EMF)
Journal of Psychosomatic Research, March 2013
Abstract
Objective
Medically unsubstantiated ‘intolerances’ to foods, chemicals and environmental toxins are common and are frequently discussed in the media. Idiopathic environmental intolerance attributed to electromagnetic fields (IEI-EMF) is one such condition and is characterized by symptoms that are attributed to exposure to electromagnetic fields (EMF). In this experiment, we tested whether media reports promote the development of this condition.Methods
Participants (N
=147) were randomly assigned to watch a television report about the adverse health effects of WiFi (n=76) or a control film (n=71). After watching their film, participants received a sham exposure to a WiFi signal (15min). The principal outcome measure was symptom reports following the sham exposure. Secondary outcomes included worries about the health effects of EMF, attributing symptoms to the sham exposure and increases in perceived sensitivity to EMF.Results
82 (54%) of the 147 participants reported symptoms which they attributed to the sham exposure. The experimental film increased: EMF related worries (β=0.19; P=.019); post sham exposure symptoms among participants with high pre-existing anxiety (β=0.22; P=.008); the likelihood of symptoms being attributed to the sham exposure among people with high anxiety (β=.31; P=.001); and the likelihood of people who attributed their symptoms to the sham exposure believing themselves to be sensitive to EMF (β=0.16; P=.049).
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