Degree of Hearing Loss

Light: 15dB-25dB

This level of hearing loss is defined as having a “slight” hearing loss. You should start taking a hearing test annually to monitor your hearing status.

Mild: 25dB-40dB

When you are in the restaurant, speech may sound like it is loud enough, but not clear. You are missing the consonants: s, t, th, and f which make up 25% of speech. It’s become hard to recognize words: thirsty, taste, past, she, almost, and first. You misunderstand a lot of words such as:

“house” sounding like “how”,

“teeth” sounding like “tee”,

“said” sounding like “ad”,

“Nice” sounding like “Eye”

“Beer” sounding like “deer”, “fear” or “near”

The problem is permanently damaged outer hearing cells of cochlea which are responsible not only for detecting soft sounds, but also for distinguishing between frequencies that are close together. It creates difficulty in listening to speech in a noisy environment.

Hearing aids can imitate the amplification provided by outer hearing cells but can not recover frequency perception. To overcome this problem, the only advance technology hearing aids with all possible features can improve the intensity of speech relative to the background, making soft sounds louder than the noise.

Moderate: 41dB-55dB

Soft speech (for example, the sound of their cars’ turn signal) is not audible anymore because outer hearing cells in the cochlea are permanently damaged.

The auditory system has lost its sharpness, as result it allows more noise to pass through the auditory pathway and makes it harder to recognize close-frequency sounds like B/P, T/D, K/G, F/V, and S/Z.

The inner hearing cells of the cochlea are also partially damaged or bent and they cannot transfer the signal to the brain. Hearing aids are now required for conversational speech.

Moderately Severe: 56-70dB

At this level of hearing loss not only are outer hair cells damaged, but inner hair cells as well. You cannot hear any consonants of speech at typical conversational levels without hearing aids. Because vowels have a lot of sound energy, they are always heard. You might hear people talking, but you cannot make any sense of what was said. Proper hearing loss treatment will help to make speech audible.

Severe: 71-90dB

Only very loud sounds can be heard. Hearing aids begin to lose effectiveness to improve speech understanding. Powerful hearing aids are becoming more beneficial to hear environmental sounds² rather than speech. Lipreading together with powerful hearing aids is an effective way to supplement speech understanding.

Profound: Greater than 91dB

The world is quiet, no sounds. Hearing aids are generally not effective for speech listening, but often improve lip-reading skills. Hearing aids are also used to hear environmental sounds.

Cochlea implants may become a solution.