by Neil Bauman, Ph.D.
A mother wrote:
My son has the typical ski-slope hearing loss associated with LVAS. His loss at 250-500 Hz is 30-40 dB, then it jumps back up to 10 dB at 1000 Hz. At 1500 Hz it drops down to 60 and it continues dropping from there. Not to sound stupid, but when his hearing aids aren’t in, is it necessary for us to speak a lot louder to him so that he can hear us? I get so confused and can’t quite get it through my head what he is hearing. Help!
I’m not surprised that you are confused. It is difficult to know what a hard of hearing person actually hears and understands.
There are two main factors at play. One is hearing. The other is understanding what you hear.
Since your son has the typical ski-slope loss, he hears low-frequency sounds at near-normal levels. This means that unless a person is talking very softly, he will hear people talking just fine since most of the volume of speech is in the (loud) low-frequency vowel sounds. Thus, you don’t need to speak loudly or shout at him for him to hear you. Just speak up in a clear normal voice.
This solves the hearing aspect. However, what you really want to know is how well he understands what he hears. This is a whole different ball game.
Since most of the intelligence of speech is carried in the (soft) high-frequency consonants which he doesn’t hear, if you speak in a normal voice, or worse yet, mumble, he may not understand a thing you say.
If you speak up and talk louder, he will hear the high-frequency sounds better, but then the low-frequency sounds will be too loud for him (and you too). Thus, the best strategy is to speak up just a bit. At the same time, speak slowly and clearly–with emphasis on good articulation. By doing this, he will be more able to speechread many of the sounds his ears miss. It will also give his brain time to put all this together and decipher what you are saying.
One more thing–and this is important–few people realize that high frequency sounds rapidly “fall out of the air” with increasing distance, Thus, if you talk to him from any distance at all, he won’t hear the high frequency sounds. As a result, speech will sound like so much gibberish. However, if you get close, and talk to him from 1 or 2 feet away, he will catch much more of these high frequency sounds–and thus his understanding will greatly increase.
A good rule of thumb is you can call to him to get his attention from a distance–but you need to get right up to him–nose to nose so to speak–so he has the best chance to understand what you are saying.