I just read the piece on Mead Killion's idea of inexpensive hearing aids. Hearing aids are not just something to slap in your ears and off you go. There are a myriad of considerations to take into account when not only choosing the setting during the first fitting, but the follow up care. This is largely due to the plasticity of the auditory system and the absolute need for the Audiology, Dispensing, Manufacturing and other related medical fields to go beyond hearing aids as a simple correction.
Auditory neuroscience has been my specialty for the last 6 1/2 years. It's taken me a long time to amass the amount of journal articles (3400) among multidisciplinary fields of medical science to be able to fit successfully those patients that range from mild to severe hearing losses. Considerations such as their current and past medical or developmental history is of utmost importance if I am to be successful at fitting the hearing aids during the first 6 months that match the initial auditory system capability and to keep pace with the neurophysiological changes that occur through stimulation and rehabilitation
For example, if I have a patient with panic and anxiety disorders and a patient who is a professional musician, even though they may have the exact same audiogram, their settings on the hearing aids will be completely different including the type of hearing aid. The P and A will be drastically below the expected settings and the PM will be above. This is due to their specific neurophsyiology makeup that give substantial control over his system in the musician and the lack of control in the P&A. The neuroanatomical differences in musicians vs. non-musicians have been established numerous times. With a 25% greater response to piano harmonics than pure tones, I need to try to match the hearing aids to musical harmonics instead of the pure tones we use during testing. Additionally, the counselling that would go into encouraging and maintaining use of the hearing aid is also going to markedly different.
An Alzheimer's patient and a Parkinson's patient's rehabilitation time is going to be significantly longer than a normal healthy control due to the depletion of Acetylcholine through the degenerative process of AD and the anticholinergic medication of the PD patient. Acetylcholine is largely responsible for auditory system plasticity during rehabilitation. A decreased availability will extend the rehabilitation time and potentially reduce the final recovery of function.
I could go on and on about the different parameters that make hearing aid fittings difficult for so called "easy" mild hearing losses. But I won't. Suffice it to say, if more University programs would concentrate on the neuroscience end of central auditory processing and the degenerative processes as a result of a hearing loss (which can begin at 20dBHL with the loss of GABA receptors creating more spontaneous activity, less temporal resolution, less frequency resolution, less spatial acoustics, etc.) Mr. Killion, with all due respect to his position in Audiology would not be so quick to relegate hearing aids to the "over the counter reading glasses" genre.
Barbara Reynolds, M.S.
Clinical Audiologist