Types of hearing loss

Hearing loss is usually described two ways: where in the ear the problem is, and what shape it leaves on the audiogram.

Where: three kinds

Sensorineural

The problem is in the inner ear — the cochlea's hair cells — or in the nerve that carries their signal to the brain. This is by far the most common kind. Genetics, loud noise, aging, some medications, and some illnesses all cause it. Many people are born with it or have it from childhood, and it is usually permanent.

Sensorineural loss doesn't only make sounds quieter. Damaged hair cells are less selective about pitch, so nearby sounds smear together. The simulator doesn't reproduce that smearing, only the loss at each pitch, so speech can be harder to follow with this kind of loss than it sounds here.

Conductive

The problem is in the outer or middle ear: something stops sound from reaching an otherwise healthy cochlea. Earwax, fluid behind the eardrum after an ear infection, a perforated eardrum, or stiffening of the tiny middle-ear bones can all do it.

Conductive loss sounds like wearing earplugs — softer, but not distorted — and it is often treatable. The simulator models it as an even reduction in level with no frequency shaping, because the cochlea itself is fine.

Mixed

Both at once: a conductive problem on top of a sensorineural one.

What: common patterns

Congenital loss is there from birth. It can take any of the shapes below, and it is often stable for years or a lifetime.

Age-related loss (presbycusis) starts with the highest pitches in both ears and creeps downward over decades. About one in three people in the U.S. between 65 and 74 has hearing loss, and nearly half of those older than 75 have difficulty hearing.¹ Try the Hearing over a lifetime slider in the simulator to hear the typical course.

Noise-induced loss leaves a notch centered around 3–6 kHz, most often at 4 kHz, with partial recovery at 8 kHz.² That recovery is what distinguishes it from age-related loss, which keeps getting worse toward the top of the range.

Cookie-bite loss dips in the middle frequencies and is often inherited. Depending on where the dip sits, voices can sound hollow, or consonants can blur together.

Precipitous loss is near-typical through the low and middle pitches, then drops off steeply — low sounds are clear, high ones almost vanish.

Asymmetric loss affects one ear more than the other. It can follow noise that came mostly from one side, such as shooting, but it can also signal something that needs investigating.