Hearing Aid Fittings and Placebo
Dawes, Powell, and Munro (2011) investigated the impact of patient expectations with regard to hearing aid fittings. Indeed, placebo effects are well known, highly recognized in medicine, and very common. The authors report that placebo can be thought of as a change in the patient’s illness due to the symbolic importance of the treatment, rather than resulting from pharmacological, physiological, or other actual physical treatments.
Placebo has been shown to be beneficial in angina surgery, as well as sham deep brain stimulation for Parkinson’s disease, and pain relief and multitude of other applications. Patient characteristics have not been shown to be consistent with regard to susceptibility to placebo. However, clinicians who appear warm, friendly, empathetic, positive, and sympathetic and those with prestige are more likely to facilitate a placebo effect. With specific regard to hearing aid studies, Dawes et al report that “unblended” studies tend to find significant effects more often than “double-blinded” studies.
The authors worked with 20 experienced hearing aid wearers (13 males, 7 females, aged 54 to 80) to evaluate “new” versus “conventional” hearing aid technologies. However, the two hearing aids were the same instrument housed in different colored shells, fitted and verified to the same National Acoustics Lab (NAL) prescription. Using a balanced design, each participant was fitted with both devices (new and conventional). Measures included speech-in-noise tests, sound quality ratings, and personal preference.
Fifteen of the 20 subjects preferred the “new” hearing aid, five could not tell any differences, and none preferred the “conventional” fitting. The authors concluded (based on their study) typical measures used in hearing aid fittings are influenced by patient/participant expectations and there is a need to control for placebo effects while fitting hearing aids.
For More Information, References and Recommendations
Dawes P, Powell S, Munro KJ. (2011) The Placebo Effect and the Influence of Participant Expectation on Hearing Aid Trials. Ear & Hearing 32(6):767-774.
Roland PS, Eaton DA, Gross RD, Wall GM, Conroy PJ, Garadi R, LaFontaine L, Potts S, Hogg G. (2004) Randomized, Placebo-Controlled Evaluation of Cerumenex and Murine Earwax Removal Products. Arch Otolaryngol Head Neck Surg 130:1175-1177.