Placebo effects in hearing-aid trials are reliable. (July 2013)

• Record Type: Journal Article
• Authors: Dawes, Piers; Hopkins, Rachel; Munro, Kevin J.
• Is Part Of: International journal of audiology. Volume 52:Number 7(2013:Jul.)
• Page Start: 472
• Page End: 477
• Publication Date: 2013-07
• Subjects: Audiology -- Periodicals; Hearing disorders -- Periodicals; Deafness -- Prevention -- Periodicals; Hearing Disorders -- Periodicals; Hearing -- Periodicals; 617.8
• DOI: 10.3109/14992027.2013.783718
• Languages: English
• ISSNs: 1499-2027

Abstract

<abstract> <title>Abstract</title> <p> <italic>Objective:</italic> A recent study suggested that placebo effects are a source of bias in non-blinded hearing-aid trials. Given the potential impact of this finding on the interpretation of non-blinded trials and design of future research trials, the objective of the present study was to investigate the reliability of this effect. <italic>Design:</italic> Using the same procedure as an earlier study, participants were told that they were taking part in a trial of new hearing-aid technology. Participants compared two devices that were acoustically identical, except one was described as "new" and the other as "conventional". Participants completed a speech-in-noise test, sound quality ratings, and rated overall personal preference for both hearing aids. <italic>Study sample:</italic> Sixteen adult hearing-aid users. <italic>Results:</italic> Participants had significantly better mean speech-in-noise performance (70.9% versus 66.8%, Z = 2.30, <italic>p</italic> = 0.02, effect size Pearson's <italic>r</italic> = 0.15) and sound quality ratings for the "new" hearing aid (8.1 versus 7.4, Z = − 2.99, <italic>p</italic> = 0.003, <italic>r</italic> = 0.28). A significant proportion of participants (75%) expressed an overall preference for the "new" hearing aid (<italic>p</italic> = 0.001, effect size φ<italic><sub>c</sub></italic> = 0.66). <italic>Conclusion:</italic> Placebo effects reliably impact on hearing-aid trials. In order to control for placebo effects, double-blind methodology is optimal. However, when double-blinding is not possible other strategies may be appropriate.</p> </abstract>