Boys Town Hearing and Balance Center
“I hear but I don’t understand.” “Everyone sounds like they are mumbling.” Many people with hearing loss can hear low-pitched vowel sounds easily but miss higher-pitched consonant sounds like /s/ or /f/ because their hearing is poorest in the high pitched range of speech.
The consonant sounds provide clarity for speech which is why you may hear that someone is talking but not be able to understand what was said. Think of the words: bash, bath, bat, bass. If you don’t hear the /s/ or /t/ sound, all of these words sound alike. Even lip reading isn’t enough. For example, the words “bat” and “mat” look identical if you are just lip reading. The words “fat” and “vat” are two more words that look identical with lip reading alone.
For people with hearing loss in the high pitches, hearing aids can’t always make the highest pitches loud enough to hear accurately. There are two main causes for this. First, hearing aid circuits cannot process the broad range of pitches or frequencies that a normal human ear can process. Second, studies suggest that ears with hearing loss may not have functioning hair cells to make high frequency sounds meaningful even if they could be made louder. That means that some talkers, especially women and children, will be harder for someone with hearing loss to understand, even with hearing aids.
Hearing aid manufacturers have tried to address this problem with a technology called frequency -lowering. Hearing aids with this technology are able to capture high frequency sounds and shift them down into lower frequency regions, as opposed to just making the high frequency sounds louder. This means that high frequency sounds of speech can be heard at lower frequencies where hearing is typically better.
Many people appreciate frequency-lowering processing from the start, but some listeners go through an adjustment period. If you have not heard the /s/ sound in years, it can be hard to get used to hearing it again, especially when it is shifted to a lower frequency. Sometimes people report that frequency lowering initially makes talkers sound like they are lisping. After a few weeks of listening and adjusting to frequency-lowering, most people say that the lisp is gone and just the /s/ sound is left in its place. The amount of frequency-lowering and the loudness of the high-frequency sounds can be adjusted as people get used to the hearing aids. There are cases where people never adjust; but, they are rare, since there are different types of frequency lowering options available from various hearing aid manufacturers. However, if a listener cannot adjust to frequency-lowering, it can simply be turned off.
Like all of our hearing aids, frequency-lowering hearing aids come with a 30-day trial period and a 2-year loss/damage and repair warranty. Call your audiologist if you would like to set up an appointment to listen to frequency lowering hearing aids. A number of different styles and sizes are available to suit different needs. Your audiologist can tell you if these hearing aids are right for your hearing configuration.