What Is Sensorineural Hearing Loss?
Sensorineural hearing loss (SNHL) is the most common type of hearing loss. SNHL is estimated to account for 9 out of 10 cases of reported hearing loss. It’s caused by damage to your inner ear structures, such as the tiny hair cells in your inner ear or the nerve pathways from the inner ear leading to your brain.
Your inner ear structures include your sensory organ or cochlea and your vestibulocochlear nerve or cranial nerve VIII.
SNHL is also known as nerve-related hearing loss because it affects the parts of the inner ear that send neural impulses to the brain.
In many cases, sensorineural hearing loss can’t be cured, but it can be treated. Treatment options include drugs, surgery, better management of any underlying conditions, and hearing aids.
Severity SNHL is often categorised on a scale or threshold of hearing loss measured in decibels. Hearing loss on this scale is described as mild, moderate, moderately severe, severe or profound.
There are several different types of SNHL, each with different underlying causes.
5 Causes of Sensorineural Hearing Loss
Presbycusis is age-related hearing loss, caused by the gradual degradation of nerve hair cells in the cochlea. Initially, it reduces your ability to hear higher frequency sounds but over time it can make lower frequency sounds unclear too, making everyone sound like they’re mumbling.
Noise-induced hearing loss occurs when excessive noise, usually over a long period, damages the fine hairs in your inner ears that send messages to your brain. People who love listening to loud music may also be damaging their hearing. Noise-induced hearing loss can also happen after a one-off exposure to an intensely loud sound, such as an explosion.
WorkSafe NZ recommends keeping noise levels below 85dB on average and 140dB at peak.
Ototoxic medications or chemicals are substances that injure your cochlea or auditory nerve. Ototoxic medicines may also affect your vestibular system, which governs your balance and spatial awareness. Some drugs are known to be ototoxic and include some antibiotics, anti-inflammatory medications and cancer chemotherapy drugs.
Hearing loss may result directly or indirectly from an underlying disease or disorder like multiple sclerosis, chronic ear infections, meningitis, measles, mumps and glue ear.
Hereditary hearing loss is a form of hearing loss that runs in families. Your genes might make you more susceptible to hearing loss by contributing to age-related hearing loss, causing some hereditary hearing impairment syndromes, or causing inner-ear mutations that affect your hearing, either at birth or in later life.
Hearing Loss Levels
Hearing loss levels range from mild to profound and are measured in decibels (dB).
Safe Listening: How Loud Is Too Loud?
Both the amount of noise and the length of time you are exposed to the noise determine its ability to damage your hearing.
Noise levels are measured in decibels (dB). Sounds louder than 80 dB are considered potentially hazardous.
The World Health Organization states there is growing concern about the increasing levels of exposure to loud sounds in recreational settings such as nightclubs, discotheques, pubs, bars, cinemas, concerts, sporting events and even fitness classes.
The rising popularity of devices such as music players and smartphones often listened to at unsafe volumes, and for prolonged periods of time, poses a serious threat of irreversible hearing loss.
Use the safe listening chart as a guide to help you protect your hearing health.
Safe Listening Chart