LSTN

Hearing Health Guide

Sensorineural Hearing Loss

Definition

Sensorineural hearing loss (SNHL) is damage to the sensory cells or nerve pathways of the inner ear that converts sound vibrations into electrical signals the brain can interpret. According to ASHA, it is the most prevalent form of permanent hearing loss in adults, accounting for approximately 90% of all cases of hearing loss.

What Causes Sensorineural Hearing Loss?

The most common causes are noise exposure and aging. Noise-induced hearing loss damages cochlear hair cells through acoustic trauma; age-related loss (presbycusis) involves a gradual deterioration of these cells over a lifetime. Both processes are largely irreversible because hair cells in the human cochlea do not regenerate, according to the NIDCD.

Other causes include genetic conditions, certain medications (ototoxic drugs such as some chemotherapy agents and high-dose aminoglycoside antibiotics), viral infections (especially mumps and measles), Meniere's disease, and in rare cases, autoimmune disorders.

Sudden sensorineural hearing loss is a medical emergency: a loss of 30 dB or more over three consecutive frequencies within 72 hours. Treatment with corticosteroids within the first 48-72 hours significantly improves outcomes.

How Sensorineural Loss Appears on an Audiogram

Sensorineural hearing loss typically produces a characteristic pattern on an audiogram: thresholds are elevated (shifted downward on the chart) at the affected frequencies. In the most common presentation (noise-induced or age-related), high-frequency thresholds (2,000-8,000 Hz) are affected first, producing a 'ski slope' or 'notch' pattern.

The audiogram will show that bone conduction and air conduction thresholds match. The signal is not being blocked in the middle ear; it is not being processed in the inner ear or nerve.

Treatment and Management

There is currently no medical cure that restores cochlear hair cells. The primary treatment for most adults with sensorineural hearing loss is amplification: hearing aids for mild to severe loss, or cochlear implants for profound loss where hearing aids are insufficient.

Since 2022, FDA-cleared over-the-counter (OTC) hearing aids are available without a prescription for adults with mild to moderate sensorineural hearing loss, significantly reducing the cost barrier to treatment.

Common Questions

Sensorineural Hearing Loss FAQ

Is sensorineural hearing loss permanent?
In most cases, yes. Damage to cochlear hair cells is generally permanent because these cells do not regenerate. The exception is sudden sensorineural hearing loss, which can partially or fully recover with prompt corticosteroid treatment. Hearing aids and cochlear implants can restore functional hearing but do not reverse the underlying damage.
What is the difference between sensorineural and conductive hearing loss?
Sensorineural hearing loss originates in the inner ear or auditory nerve. The sensory mechanism itself is damaged. Conductive hearing loss originates in the outer or middle ear, preventing sound from reaching the inner ear efficiently. Sensorineural loss is usually permanent; conductive loss is often treatable. Mixed hearing loss has components of both.
Can sensorineural hearing loss get worse over time?
Yes. Age-related sensorineural hearing loss (presbycusis) is progressive by nature. Noise-induced loss can worsen with continued noise exposure. The rate of progression depends on genetics, lifestyle, and ongoing noise exposure. Wearing hearing protection significantly slows progression from noise.
At what point should someone with sensorineural hearing loss get hearing aids?
Most audiologists recommend considering hearing aids when thresholds reach 40 dB or greater in the speech frequencies (500-4,000 Hz), or when hearing loss is clearly affecting daily life: difficulty following conversations, frequently asking for repetition, or needing the TV at high volume. Earlier intervention tends to produce better outcomes. The audiologists at my clinics would note that the patients most resistant to trying aids were often the most surprised by how much they helped. The decline is gradual enough that you stop knowing what you were missing.
What Is Sensorineural Hearing Loss? Causes, Symptoms & Treatment — LSTN