by Neil Bauman, Ph.D.
A man explained:
I always wondered what the ‘immediate after-whoosh’ was while wearing my hearing aids, and was enlightened to find out that it was something called ‘entrainment’, which only those who wear hearing aids hear. Are there any techniques or tips for listening through, or coping with, entrainment, or is it something I’ll just have to get used to whenever I wear my hearing aids?
Probably “entrainment” is a new word to most readers. It’s certainly not a word that is bandied about in casual speech!
Entrainment is a relatively recent phenomenon as it applies to hearing aids since it only occurs in hearing aids that have anti-feedback circuitry in them. Most hearing aids manufactured in the past 10 years or so have anti-feedback circuits. As a result, entrainment may actually be quite common now. I know it happens with my hearing aids under certain conditions.
What happens is that when a sound (tone) is held for more than a fraction of a second, the anti-feedback circuit in your hearing aids thinks that the hearing aid is beginning to feedback (whistle) and so it attempts to squelch that sound. This often happens when you are listening to music for example. As I understand it, the anti-feedback circuitry and the hearing aid’s amplifier both try to synchronize the tone with each other, thus causing the sound to be prolonged (which greatly distorts the original sound).
I hear that with my hearing aids if I listen to music with my speech program. When listening to music, I need to switch to my music program where the anti-feedback circuitry is turned off. This immediately eliminates any entrainment.
I have a customer who has fit 2 girls with hearing aids. (they are sisters) One sister has no problem with her hearing aids, the other sister is complaining that she hears feedback from the other sisters hearing aids and it is very loud (fitter says “painfully loud”)? The feedback is not audible to the fitter? The fitter wants to know if this could be due to entrainment?
Hi Joanne:
My first question is how close are the girls to each other when the one sister hears this sound? Does it happen every time they are close, or just occasionally?
Personally, I don’t think it is entrainment, but it is possible that one hearing aid is picking up RF from the other hearing aid.
In any case, the fitter should be able to hear this sound also if he/she listens to the hearing aid via his/her stethoscope and duplicates the situation when the one sister hears this sound.
Regards
Neil
I lost my five year old hearing aides that had a feedback circuit, but no entrainment. I was told those were by Rexton, for Costco. Now, ALL the hearing aides I have tried, Rexton, Phonak and one other, have unacceptable entrainment. I have given them all back for refund, and now have none. But the entrainment affected not only music, but voices. I could not understand my wife! (no jokes, please 🙂 ). Two questions: Is there a brand under $4000 that has conquered the entrainment issue, or, is it possible to find a source and buy 5-year-old Rextons??
I have just been fitted with new aids. Having worn aids for most of my life I had never experienced entrainment and it took a while for the audiologist to work out what was causing the problem. Basically it caused distortion of music and voices such that they sounded very discordant. We worked out that it was the feedback management system in the hearing aids. This has now been turned off and all is fine now. No more discordant sounds. Hope this helps.
Hi Nicola:
The feedback management system sure messes up music. This is because when you hold a note, the hearing aid thinks the sound is feeding back and then tries to squelch it. This makes it sound terrible.
I have one program for listening to music that has the feedback turned off. This works just fine for me. The other programs all have it turned on.
Cordially,
Neil
Have them fit you in linear mode not in nonlinear.
Hi Scealratha:
Setting your hearing aids in linear mode means that you no longer have the compression you may need to hear soft sounds while still keeping loud sounds from being too loud.
Cordially,
Neil