Browsing by Author "Stickler, Emma"

Objectives: Some individuals who live near wind farms have reported symptoms which they attribute to wind turbine infrasound (WTIS). The primary aim of this study was to investigate whether these individuals are perceptually sensitive to WTIS and thus possibly susceptible to WTIS-induced symptoms. A secondary aim was to investigate whether sham WTIS elicits stress, thus providing support for a nocebo explanation of symptom attributions. Methods: A series of laboratory experiments was conducted with participants who attributed experienced symptoms to wind turbines (symptomatic group, n = 11) and controls who did not (asymptomatic group, n = 13). Discrimination ability (d’) for wind turbine noise with and without infrasound (≤ 20 Hz) and low-frequency sound (≤ 100 Hz) was estimated with a two-interval same–different forced-choice task. Participants were also blindly exposed to WTIS for 7.5 minutes. Finally, participants underwent a sham infrasound exposure experiment without acoustic stimuli. Participants’ perceived stress level and electrodermal activity were measured to evaluate participants’ reactivity to WTIS and sham infrasound. Results: Participants were not found to discriminate wind turbine noise with infrasound from wind turbine noise without infrasound or to react to WTIS exposure. Participants could discriminate wind turbine noise with low-frequency sound from wind turbine noise without low-frequency sound. No differences were observed between groups. Sham infrasound did not elicit stress in either group. The symptomatic group generally reported greater levels of perceived stress and more pre-existing symptoms than the asymptomatic group. Conclusions: The results do not suggest an association between symptoms attributed to wind turbines and perceptual sensitivity to WTIS. Sham infrasound did not increase stress, and so symptomatic individuals may not associate symptoms with WTIS strongly enough for a nocebo response to occur. The greater reports of stress and pre-existing symptoms in the symptomatic group imply that symptoms might be misattributed to WTIS. Disturbance caused by audible low-frequency wind turbine noise might also influence symptom attributions.