Because of the inherent problems with 16 bit hearing aid architecture, the “front end” of the hearing aid is frequently overdriven by intense inputs- specifically it is the analog to digital (A/D) converter and associated pre-amplifiers that is the culprit. Intense inputs frequently come from music, but a hearing aid wearer’s own voice can also overdrive the input. Normal conversational speech is not typically a problem.
The question that arises is “given a hearing aid that seems to be great for speech, what can be done to also make it great for music?” This has been covered in previous blogs so I will not retrace my steps, but following are four easy-to-implement strategies that improve the fidelity of music over what a hearing aid may currently provide.
Strategy #1: Turn down the input (stereo) and turn up the hearing aid volume (if necessary). If the excessive level of the input to the hearing aid does cause distortion of the A/D converter, then turn down the input if at all possible. If traveling in a car, turn down the level of the radio and (if necessary) turn up the level of the hearing aid to compensate. The output will be the same, but the input would have been reduced to a level that is well within the operating range of the front end of the hearing aids.
Strategy #2: Removal of hearing aid for music. Given the higher level inputs of music, the required gain may be close to 0 dB for a desired output. Even for an 85 dB sensori-neural hearing loss at 1000 Hz, while a person may require 45 dB gain for certain speech sounds, they may only require several decibels of amplification for many types of music. The best strategy for many hard of hearing consumers may be to simply remove their hearing aids when listening or playing music.
Strategy #3. Use Scotch tape. This is the lowest technology level and is perhaps the easiest to implement clinically. Like the use of a less sensitive microphone (e.g. one that has reduced sensitivity to the lower frequency region), using a temporary microphone covering such as Scotch tape shifts its ability to transduce sound downwards by about 10 dB for three or four layers of the tape. The A/D converter is therefore presented with a signal that is 10 dB less intense and can often be within its optimal operating range. There needs to be some trial-and-error and the hard of hearing consumer can be instructed to play with one, two, or three pieces of tape over both hearing aid microphones. The exact number does depend on the gauge and the brand of the tape. Attenuations of 10 dB which are relatively flat across the frequency range have been measured using this clinical “low tech” approach.
Strategy #4. Change the musical instrument– This is a common strategy used by many musicians. Change to an instrument that has more of its energy in an audiometric region of better hearing. Many violin players have switched to the viola which is a fifth lower in frequency. For many this is a simple approach that has extended a musicians’ enjoyment of their music for many years.
The above strategies are just a few of the many that have been found to be useful over the years. The Association of Adult Musicians with Hearing Loss is an organization of hard of hearing and deafened musicians as well as interested hearing health care professionals who work with those in the performing arts. In addition to their very active listserv blog, they have recently come out with a book entitled, “Making Music with a Hearing Loss” edited by Cherisse W. Miller (2011). Chapter 4 of that book is aptly entitled “Personal Stories and Strategies” where many musicians talk about what works best for them. Copies of this excellent book can be obtained through the AAMHL.org site.
Also, the AAMHL will be hosting a webinar this weekend (Saturday Sept 8 from 1 PM – 3 PM EST) on this very topic.
To register go to (or paste the following address in your browser):
http://www.anymeeting.com/PIID=E058DF848747
Whether it’s a singsong or a piece by Mozart, familiar music and song played regularly (and especially those which invite participation) can help build a stronger memory for a child. The developing brain is encouraged to remember the next part of a familiar song as it is heard – it’s almost like a memory exercise.