Music and the PCAST Recommendations: Part 1

Marshall Chasin
February 16, 2016

Most of my blog entries are not particularly political. They can, and do touch on certain advocacy items if I feel that it may affect the accessibility of services or products, but by in large, I have situated my blog entries in more of a technical and clinical framework.

The recommendations of the President’s Council of Advisors on Science and Technology (2015) do definitely touch upon issues of accessibility and service delivery, but I suspect that contrary to the PCAST report, at least for musicians  and those of us mere mortals who just like to listen to music, (and most likely the more general hard of hearing public) the PCAST recommendations will minimize accessibility and service delivery, as well as potentially cause further hearing deterioration. There is a principle of universality and while this is generally laudable, this can be short sited and naïve.

There are four PCAST recommendations- two are designed to improve the mobility of hearing aid prescriptions across state jurisdictional lines. These are the third and fourth PCAST recommendations (summarized by myself):

  1. Audiologists should provide the audiogram to the consumer so that the consumer can purchase the hearing aid anywhere that they would like; and
  2. These hearing aid prescriptions can be dispensed across borders in any state.

These two recommendations have more to do with the way that hearing aid prescriptions are handled across jurisdictions in the United States and while this can be quite significant (since state laws typically trump federal laws), these in themselves are more “political” statements that may impact access federally but not as much on the local level where service delivery is typically provided. Further, these recommendations may not make sense in other countries around the world.

 

The first two PCAST recommendations of substance (summarized by myself) are:

  1. The FDA should designate a distinct category of “basic” hearing aids for mild to moderate sensory/neural hearing loss and should be approved for “over the counter” sale which does not require audiological input; and
  2. The FDA should withdraw its draft guidance regarding PSAPs and that this should be replaced with basic hearing aids according to the first recommendation.

Unlike the third and fourth recommendations mentioned above, these two are very significant, and if I may be blunt, demonstrate the naivete and lack of knowledge of those consumers and other non-professional audiologists that comprised the membership of PCAST.

I suspect that the members of PCAST confused hearing aid delivery with that of eyeglasses. In the optical domain, a prescription is a measure of acuity; in the audiological domain, a prescription is based on factors that include measures of acuity as one of many factors.

An optical prescription is for a “conductive” pathology where the light waves are altered due to a mechanical alteration of the shape of the eyeball.

In the vast majority of eyeglass fittings, the sensory organ (retina) is fine. Myopia is primarily a conductive loss.  In contrast, the vast majority of hearing loss is not conductive, but is sensory (or sensory/neural).

Despite both “conductive” and “sensory/neural” being descriptions of hearing loss, that is where the comparison stops.  A conductive hearing loss is analogous to merely turning up the volume again, whereas a sensory/neural hearing loss is analogous to trying to adjust the radio when it is off-station.  No amount of “mere” volume control adjustment will resolve the problem.

Other than the “conductive” versus “sensory/neural” differences, another major difference is that there is no maximum input of light that needs to be specified with eyeglass lenses; in contrast, with audition, there needs to be a maximum output into the ear of the sound pressure- too high and continued hearing degradation can occur.

The PCAST recommendations 1 and 2 ignore the fact that an optimal hearing amplification (whether it’s caused by a hearing aid that is prescribed or any number of PSAPs or hearables that can be purchased over the counter or through the internet) is not necessarily the one that “sounds the best”. There is a large body of literature going back decades showing that a “preferred” setting is frequently one that is suboptimal in terms of speech intelligibility, and more recently, suboptimal in terms of music.

In subsequent parts of these blog entries, various elements of hearing aids that the PCAST recommendations touch upon, will be discussed.

 

 

 

 

 

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