What is Hearing Loss?
Hearing loss describes the inability to hear fully or partially in one or both ears. The loss can be temporary or permanent and sounds around you will no longer be clearly heard.
Over five percent of the population have hearing loss and one in six people have hearing impairment. Hearing loss falls into four categories, mild, moderate, severe, or profound. (1)
Hearing loss can affect daily life when you are unable to communicate or hear what is going on around you.
Causes
Hearing loss can be classed as sensorineural, conductive or mixed.
Conductive hearing loss impairs the passage of sound from the ear canal to middle ear (eardrum) and the inner ear.
Sensorineural hearing loss happens when tiny hair cells which transmit sound become damaged within the inner ear. It could also be interference in the neural pathways to the brain.
When both the inner and outer ear are compromised then hearing loss is classed as mixed. (2)
We will now detail the causes of conductive and sensorineural hearing loss:
Conductive Hearing Loss
Earwax and Foreign Objects
Earwax (cerumen auris) is a natural secretion which protects the ear from foreign particles and lubricates the ear canal. It usually self cleans, working its way out of the ear assisted by the jaw when we talk or chew.
The practice of cleaning ears with cotton buds, wearing headphones or hearing aids compacts the earwax. When this happens a blockage prevents sound from traveling along the ear canal causing hearing loss.
Blockage from any foreign objects within the ear canal will also impair hearing. (3)
Ear Infection
Infections of the middle ear are a common complaint in children. We all have a tube (eustachian) that allows drainage from the middle ear. In children this is not fully formed and can block causing infection.
Fluid can also build up in the middle ear without infection. As a result hearing can be impaired, it may be like trying to hear with your ears submerged in water. (4)
Infections can also occur in the ear canal, often due to bacterial, viral and fungal infections or allergies. They are also common among people who swim because germs can enter the ear canal from the water.
Outer ear infections can also affect hearing. (5,6)
Perforated Ear Drum
There are occasions when the eardrum can be damaged and a small hole forms. This could be due to pressure, trauma, ear surgery or infections.
The result is a loss of hearing in the affected ear. (7)
Eustachian Tube Dysfunction
There is a narrow tube which connects the back of the nose to the middle ear called the eustachian tube. It protects the middle ear from infections and helps drain fluid.
Another function is keeping air pressure equal on each side of the eardrum. This is why when we travel at altitude, whether in an airplane or driving up a mountain, we feel the need to swallow. This opens the closed tube and equalizes the pressure in the ears.
If this tube does not work properly an imbalance of pressure can impair hearing or even damage an eardrum. (8)
Sensorineural Hearing Loss
Loud Noise
Exposure to loud noise can be sudden, as in the sound of a gunshot or an explosion. On the other hand it can be prolonged like frequently listening to loud music through earphones. Another example could be your workplace might not be a quiet zone therefore you are subjected to loud noises like power tools or traffic.
All these situations of noise exposure can damage the tiny hairs in the inner ear and because they cannot regenerate, the consequence is hearing loss. (9)
Aging
As we age the hairs in the inner ear and the nerve signals to the brain degenerate therefore hearing loss ensues. (10)
Viruses or Diseases
Certain viruses and diseases can cause sensorineural hearing loss. These include mumps, meningitis, multiple sclerosis, HIV and ménières disease. (11)
Head Trauma
Injuries to the head as a result of an accident or fall can damage both the nerves and inner ear. This can particularly be the case if the skull is fractured.(12,13)
Conductive and Sensorineural Hearing Loss Combined Causes
There are some causes which affect both types of hearing loss.
Hereditary factors like abnormalities of the outer ear and/or the small bones of the middle ear or inner ear structures can result in hearing loss or deafness. (14)
Tumors or cysts in the area of the ear or in the ear itself, whether benign or not, can interfere with hearing. (15)
Otosclerosis is a disease which knits together bones in the middle or inner ear. As a result sounds are not processed effectively and hearing is lost. This is correctable when it happens in the middle ear but permanent in the inner ear. (16)
Symptoms
You may not always realize you are losing your ability to hear clearly. The symptoms can be gradual but there are changes you may recognize.
It might be harder for you to hear conversations and you may misunderstand what people are saying to you. This might be more apparent in places where there is a lot of background noise like on a busy street. Eating out at a full restaurant or paying at a checkout in a supermarket can also be challenging on auditory senses.
Another indicator of hearing loss is not hearing properly the first time, you might ask people to repeat what they have said to you. You could find that you turn the television volume up more than you used or listen to music more loudly.
Concentrating harder to hear or trying to watch peoples lips as they talk are other telltale signs. You could also find conversations on the telephone or in groups are taxing.
When it comes to hearing loss in children there are signs to look out for. These include delayed speech or problems pronouncing words properly. Language development can be slow and they often appear not to pay attention. School work will also be below the standard expected. (17)
If your hearing loss is accompanied by other symptoms you might need referral to a ear nose and throat specialist. These include, active drainage or bleeding from either ear along with pain.
Your hearing loss may be sudden or progress quickly and you may experience dizziness. An obstruction like a wax plug, foreign object, pus or blood, which can be seen needs to be dealt with. (18)
Diagnosis
Hearing loss can be hard to accept and it may be loved ones who initially point it out. Your doctor will take full medical history of both yourself and your family. They will want to know what symptoms you are experiencing and how long you have had them.
A physical examination of your ears, nose and throat will be carried out. If the cause is not identified you may be referred to a specialist doctor for hearing tests.
A full hearing test will determine the extent and type of hearing loss you are experiencing. This will identify whether a hearing aid will benefit you (19)
FAQ
What is hearing loss? Hearing loss describes the inability to hear fully or partially in one or both ears. Its onset can be gradual or sudden and it be temporary or permanent.
What causes hearing loss? Many things can cause impaired hearing. Head trauma or a sudden loud noise can have immediate effect while infections and diseases cause gradual loss over time.
How do doctors test for hearing loss? Following a physical examination, if hearing loss is suspected then a full hearing test will be done.
When should you go to the doctors with hearing loss? Loss of hearing can impact everyday life. It can leave you feeling isolated, lonely and frustrated when you are unable to communicate. If you have any concerns your hearing is becoming impaired you should see a doctor.
Can you prevent hearing loss? Whilst you might not be able to prevent hearing loss, there are things you can do to protect your ears. Don’t put anything in your ears, including cotton buds, tissues or cotton wool. When watching television or listening to music keep the volume down, especially when using headphones. If you work in an area where there is a lot of noise, use ear defenders. (20)
What can relieve hearing loss? There are times when treatment with medication or removal of wax will improve hearing loss. Hearing aids may help you hear more clearly.
Is there surgery for hearing loss? Dependent on the cause of hearing loss there are surgeries that can be done to try and correct the hearing. There is also the option to implant a hearing device. (21)
What can help manage hearing loss? Apart from hearing aids, there are other methods of communication that can help people whose hearing is impaired. Learning sign language, lip reading and body language can all help. (22)
Summary
Hearing loss describes the inability to hear fully or partially in one or both ears. The loss can be both temporary or permanent and the onset can be gradual or sudden.
There are many things that can cause hearing to deteriorate, however there are things we can do to protect our ears.
As we age hearing loss is sometimes inevitable. However, early recognition means you can seek help from a medical professional.
The good news is technology is always developing, therefore hearing aids are constantly improving and becoming more adaptable. (23)