Noise Reduction In Hearing Aids

Noise Reduction In Hearing Aids

Recently in a local hearing clinic, a client’s concerns were discussed. “I’m afraid I won’t like them. My brother in law bought two hearing aids, and he keeps them in a drawer in the kitchen.” While the number of people dissatisfied with their hearing aids hovers around 50%, the hearing aid industry is hard pressed to decrease the number of returns, and increase the average daily use of each aid. In order to accomplish this, hearing aid manufacturers must answer the most often heard complaint: “It doesn’t work well in noise.” Unfortunately, a hearing aid will never be able to accomplish the sifting and sorting that is carried out in the human brain. While a person with normal hearing sits in a restaurant, he can distinguish a conversational speech signal that is as little as three decibels greater than the ambient noise. On the other hand, a person with a 30-decibel sensorineural loss might need the speech signal to be 15 or more decibels greater than the ambient noise. The hearing aid’s task is to acoustically or electronically compensate for both the neurological shortcomings of the hearing impaired person and the wide band increase inherent in any basic amplifier.

Effect of Low-Frequency Gain Reduction and its Relation to Upward Spread of Masking. Perhaps in the future, correct hearing aid selection combined with ever advancing technology will yield the comment, "Boy, this thing works great in a noisy restaurant!"� Alas, that is the nature of the beast. It then enhances the sound from the front, and reduces background sounds from the sides and rear. This concept seems natural based on the upward spread of masking principle. According to the flyer, "One picks up sound in front of you while a second picks up sound from the sides and rear. 1991) shows that both algorithms provide significant high frequency gain at low levels. As shown, the signal processorgenerates a sound wave that is out of phase with the incoming signal. "Our tests to date have shown that the signals produced with our magnetic hearing device are very nearly those of natural acoustic sound. The Phonak MicroZoom; uses an electronic approach.