Everybody knows that if you have a hearing loss, you don’t hear many of the sounds around you. Other sounds may be heard, but they’re not quite loud enough.

Another common problem for people with hearing loss is that many sounds are simply too loud. How can someone who has a hearing loss find many sounds loud enough to be uncomfortable—even painful??

This hypersensitivity to loud sounds is called recruitment and is not unusual for someone with a sensorineural (inner ear) hearing loss. The explanation lies in how the ear works.

Sensorineural loss is the most common type of hearing loss. In cases of sensorineural hearing loss, some of the hair cells of the inner ear have been damaged and are not responding to softer sounds. However, other hair cells, the ones that respond to louder sounds, may be just as sensitive as ever.

Thus, a person with sensorineural hearing loss (and recruitment) might not hear soft sounds at all; might hear moderate sounds (although not quite loud enough); and loud sounds might suddenly be too loud because the inner ear hair cells have suddenly been activated.

The Comfortable Listening Range

As a result of this hypersensitivity, most people with hearing loss have a limited range of comfortable hearing. Many sounds are too soft to be heard, while others are simply too loud to be tolerated.

To put it in numbers, someone with normal hearing might have a comfortable listening range of 100 decibels (the range between what is barely heard to the limit of what can be tolerated). The typical comfortable listening range of someone with a moderate loss might be only 45 decibels—a much more limited range.

Hypersensitivity and Hearing Aids

There are important implications for hearing aid use. Hearing aids must amplify sounds enough to be heard, but not amplify sounds beyond the user’s tolerance level. Older hearing aids were limited in their ability to do this. If the hearing aid amplified soft sounds enough to be heard, loud sounds would be too loud; if loud sounds were kept in the comfortable range, soft sounds would be too soft. Usually the hearing aid user would use a manual volume wheel to try to keep sounds in the comfortable range.

The new generation of high technology hearing aids, with microchips, programmability and digital processing, are much more successful at handling the problem of recruitment. Modern hearing aids monitor the incoming sound and adjust automatically. Soft sounds may still be soft and loud sounds may still be loud (as they are for everyone), but today’s hearing aids are much more effective at keeping sounds within any individual’s comfortable listening range.