The Differences Between Hereditary and Noise-Induced Hearing Loss
Hearing loss is not a one-size-fits-all idea. Different causes of hearing loss, including noise-induced and hereditary, present differently in terms of sound tones lost.
Noise-Induced vs. Hereditary Hearing Loss
One type of hearing loss is noise-induced, which occurs after being around too much noise for long periods of time. The cochlea is a snail-like structure inside the ear with hair cells that collect and carry sound to the auditory nerve. As Cassandra Garver, a licensed Hearing Instrument Specialist and owner of Lifetime Hearing Solutions, explained, “…when noise is introduced for long periods of time, those hair cells … start to essentially just get weak and bend over because they’ve just been in use for so long.”
Hereditary hearing loss, on the other hand, presents as a different type of hearing loss. While the hair cells bend over, just as they do with noise-induced hearing loss, hereditary hearing loss is more of a flat loss instead of a sloping loss.
These two terms, flat loss and sloping loss, are used to describe the tones lost. Hearing tests use frequencies ranging from low tones, 250 Hz, to high tones, 8,000 Hz. A flat loss signifies the same degree of loss across all frequencies.
Sloping loss, which is associated with noise-induced hearing loss, shows up as worsening hearing as the frequency gets higher. Low tones are on the inner cochlear coil, and the frequency increases as the cochlea spirals out. For sloping loss, low tones are in the normal range. “As the frequencies get higher, the hearing decreases, so it shows more of a slope on the graph,” said Garver.
While a specific hearing aid is not needed for each type of hearing loss, some are a better fit depending on the kind of loss.
Sloping loss, which is seen in noise-induced hearing loss, is best remedied with a behind-the-ear hearing aid with a receiver in the canal. This is the best hearing aid for this type of hearing loss because it is considered more of an open fit. Those with sloping loss can still hear low tones in a normal range, and the behind-the-ear hearing aid allows them to use their natural hearing for low tones and only assists in high tones as needed.
Those with a flat line loss can also use the behind-the-ear hearing aid with a receiver in the canal, but it will need to be fitted more closely. Closing off the ear canal prevents any natural sound from coming through. Instead, all the sound will come through the hearing aid.
Custom hearing aids are another option, but they are best suited for those with flat line hearing loss because the entire hearing aid is in the ear canal, not just the receiver. When explaining why those with sloping hearing loss should refrain from a custom hearing aid, Garver said, “you’d just run into the patient or wearer feeling plugged up… they have some good hearing, and they’re not able to use that if their ear is completely covered by the hearing aid.”