Hearing loss occurs naturally as we get older, becoming more pronounced from around 55 years of age.
In fact, our hearing can begin to deteriorate in our 20s, especially if we're often exposed to loud noises (for example in our work environments).
There are a number of other causes too - including a build-up of wax in the ear canal, severe colds, the onset of inner-ear conditions such as Ménière's disease, or as a consequence of developing diabetes. Other conditions such as tinnitus (ringing in the ears) can often be a sign that hearing loss is present.
How we hear:
- The outer ear captures sound vibrations from the air as they travel down the ear canal.
- The ear drum vibrates and passes sound into the middle of the ear - where the tiny bones transmit sounds to the inner ear.
- The inner ear (cochlea) transmits the signal to the auditory nerve via tiny hair cells.
- The auditory nerve transmits the signal to the brain for us to process.
1. Conductive hearing loss
Conductive hearing loss occurs when there is a blockage in the outer or middle ear, or both. This makes it difficult for sound waves to reach the cochlea (the part of the ear that converts sound waves into electrical signals to send to the brain). A conductive loss can be temporary in nature and in some cases may be treated medically or surgically. Hearing aids may also be prescribed for patients with a conductive hearing loss.
2. Sensorineural hearing loss
This occurs when there is a problem in the inner ear or the auditory nerve. The most common condition associated with a sensorineural hearing loss affects the hair cells in the ear that are responsible for picking up high-pitched sounds. This is referred to as presbyacusis or age-related hearing loss.
Damage to the hair cells can be a result of:
- Excessive noise exposure
- Meniere's Syndrome
- Diseases such as meningitis
- Ototoxic drugs (drugs with side effects that affect hearing)
Because sensorineural loss often affects the hair cells that detect soft, high-pitched sounds, it can be very difficult to hear speech clearly, especially when there is competing background noise. This type of loss is permanent, however it can usually be addressed with hearing aids.
3. Mixed hearing loss
When a conductive hearing loss occurs in combination with a sensorineural hearing loss, it is known as mixed hearing loss. Mixed hearing loss usually responds well to hearing aids, and other treatments to address the conductive component of the hearing loss may also be sought.