While the frequency of hearing aid problems caused by earwax has dropped since the early 1990s, when close to 70 percent of malfunctioning aids returned to the manufacturers had this problem, it is still a significant number.Hearing aids are delicate electronic instruments and they are generally very sensitive to any situation in which the aid is exposed to excessive moisture, such as high humidity or perspiration. Hearing aids also do not function very well when the sound channel is blocked by earwax, when wax or moisture impedes the proper vibration of the hearing aid receiver (the "loud-speaker"), or when condensation appears in the tubing of behind-the-ear (BTE) hearing aids. Indeed, often the first sign of humidity or a wax-related problem is when the amplified sound appears to be weak and somewhat distorted.
While the frequency of hearing aid problems caused by earwax has dropped since the early 1990s, when close to 70 percent of malfunctioning aids returned to the manufacturers had this problem, it is still a significant number. According to one recent survey, the infiltration of earwax in the sound bore is still the reason why some 30 to 60 percent of all custom hearing aids malfunction. This problem remains in spite of many creative efforts to block the wax from entering the hearing aid, such as various kinds of wax traps and adhesive strips designed to protect the opening. It is apparent that the problem represents a major cost and inconvenience factor for both manufacturers and consumers. It is ironic that the correct operation of the most expensive and sophisticated hearing aid can be defeated by such a mundane factor as wax in an ear canal, but that is the reality.
In two studies reported several years apart, Richard Navarro and his colleagues demonstrated how the ultrasonic cleansing of hearing aids could restore the correct operation of malfunctioning hearing aids. In their iudgment, these aids were functioning poorly not only because of wax pressing against the diaphragm of the hearing aid receiver (the "loudspeaker" of the hearing aid), but also because of the corrosive effects of moisture and perspiration on the electronic components.
In these studies, the hearing aids (after the batteries were removed) were immersed in a beaker filled with three percent hydrogen peroxide and then placed in an ultrasonic cleanser for five minutes. After removal, the remaining moisture was suctioned off the hearing aids and they were placed in a hot air "drying cup" for a few minutes. This treatment has the effect of both removing the cerumen and eliminating any residual moisture. Electroacoustic analysis revealed that the performance of the hearing aids could be restored through this method, though sometimes the hearing aids required a second treatment before optimal results could be achieved. In his practice, Dr. Navarro is able to restore many hearing aids to optimal functioning without the necessity of returning them to the manufacturer, an expensive and time-consuming practice.
As described by Dr Navarro in the articles, however, this method would simply be too elaborate for consumers to emulate.
While various types of more or less effective inexpensive Dri-Aid kits have been available for years, a recently introduced product, the Dry & Store Hearing Aid Conditioning System, has been specifically designed to permit consumers to dry their hearing aids safely and efficiently. It is an electrical appliance that provides the three essential ingredients required to effectively dry a hearing aid: heat, moving air, and a dessicant to absorb the moisture that the heat and moving air release.
The rationale of the unit is in the integrated operation of all three elements, i.e., the heat to release the moisture from the inner workings of the hearing aid while the moving air directs the moisture to the absorptive material. The device is programmed for an eight-hour cycle after which it turns itself off. While the unit does not directly remove earwax from the hearing aid sound channel, it will eliminate the moisture from it thus making residue flaky and easy to remove.
Besides removing moisture and fostering the elimination of earwax, the Dry & Store unit claims another beneficial action. There is a presumption that itchy ears and some external ear infections may be due to sub-clinical levels of bacterial growth on the hearing aids and ear-molds (why it is imperative that they be clean !). In the first eight minutes of the eight-hour cycle, a germicidal lamp operates to sanitize the hearing aids by effectively killing the bacteria and other flora that grow on the hearing aid and/or earmold.
While there is no independent confirmation of this claim, a survey conducted by the company found that 72 percent of respondents reported that the incidence of itching and recurring ear infections were reduced. In the same survey, 77 percent reported that their aids "sounded better" since they began using the Dry & Store, presumably because moisture was eliminated from the diaphragms of the hearing aid receiver and microphone.
Unlike simple Dri-Aid kits, the batteries need not be removed prior to placing hearing aids in the Dry & Store unit. In a study conducted by the Eveready Battery company, when the external humidity conditions were 50 percent, battery life was unaffected by the use of the Dry & Store unit. When the external humidity conditions were 85 percent, the use of the unit actually increased battery life by 10 to 20 percent. The explanation given was that a high humidity environment normally affects battery performance, but that this effect was eliminated when the hearing aid (with batteries inside) are stored in a low humidity environment the Dry & Store unit). It should be pointed out that only this company's zinc-air batteries were used in this investigation and that similar results may not be obtained with batteries from other manufacturers (although the results should apply to a certain extent, as long as zinc air batteries are being used).
Further information on this product can be obtained from www.eartech.com or by calling 800-327-8547
This column was supported, in part, by GRANT #H133E980010 from the U.S. Department of Education, NIDRR, to the Lexington Center. Mention of products or companies by the author does not indicate SHHH endorsement, nor should exclusion suggest disapproval. Since everyone's communication problems and needs vary, SHHH suggests consulting with your hearing health professional.