A Field Study on the Effect of Relative Humidity on Hearing Aid Receivers
By Hall, C. Mike; Croutch, Carl; Hearing Review, Vol. 17, No. 1, pp. 32-35Publication Date: January 2010
Study explored the relationship between relative humidity (RH) and problems encountered with hearing aid receivers. The study was undertaken in light of observations of an apparent correlation between the amount of RH and proximity of the hearing aid receiver to the tympanic membrane with the incidence of receiver problems. RH was measured on a group of 48 patients wearing in the canal (ITC) hearing aids. A brief questionnaire was used to obtain a history of each patient’s middle ear and cerumen (ear wax) problems. Based on questionnaire results, participants were divided into a 27-member Receiver Problem Group (RPG) and a 21-member No Receiver Problem Group (NRPG). The RH was measured for all participants with a probe located where the hearing aid receiver exits the hearing device in the ear canal. In the NRPG group, none had RH measurements exceeding 60 percent; however, within the RPG group, only 6 of the 27 patients had RH measurements in the normal range, while 21 patients had measurements above 60 percent RH. Based on study results, the authors recommend the development of insertable and removable devices, similar to the Knowles metal impedance cylinder originally designed for use in behind the ear (BTE) devices, but with a moisture absorbing material in place of the impedance filter. Further, the development of a low-cost RH measurement device is recommended for identifying patients with abnormally high RH values.
Published by: Ascend Media LLC (Website:http://www.ascendmedia.com)
Link to text: http://www.hearingreview.com/issues/articles/2010-01_05.asp
