The ear has external, middle, and inner portions. The outer ear is called the pinna and is made of ridged cartilage covered by skin. Sound funnels through the pinna into the external auditory canal, a short tube that ends at the eardrum.
Why do we hear?
Different levels of hearing were first noticed at the close of World War II by Dr Ramsdell while he was working in Deshon Army Hospital in Butler, Pennsylvania, which was a veteran’s Administration Hospital.
He had the opportunity to observe young adults who had lost some or all of their hearing whilst on active service, and recognised the four stages of how we use our hearing, particularly the importance of the ‘feeling of oneness with an active environment’. These young adults constantly complained that the world seemed dead.
Ramsdell became aware that we rely on our hearing for:
- understanding speech – the symbolic level. Informs, educates and entertains.
- appreciating sounds that please us – the aesthetic level. Gives pleasure.
- recognising sounds that alert us – the warning level. Alerts and prepares.
- recognising the changing background sounds of the world around us – the primitive level. Auditory background for daily living.
How does this work in practice?
You are sitting in a room near an open window which looks out onto a busy road. The sound of traffic is comforting or irritating depending your your reaction to the noise. All the same you know you can hear it. Primitive level.
You remember that you have forgotten something for a meal you are making and you decide to drive to a local shop. You listen to the car radio which tells you that the traffic is heavy on the main road. Sure enough, the noise of the traffic is louder as you approach. The spoken word and the background sound mean the same thing – heavy traffic. Symbolic level.
You hear a siren and know that you will need to pull over and wait for the emergency vehicle to pass. This is because the sound of the siren has alerted you and given you an instruction. Warning level.
How does normal hearing work?
The three parts of the ear anatomy are the outer ear, the middle ear and the inner ear. The inner ear is also called the cochlea. (‘Cochlea’ means ‘snail’ in Latin; the cochlea gets its name from its distinctive coiled up shape.)
The outer ear consists of the pinna, ear canal and eardrum
The middle ear consists of the ossicles (malleus, incus, stapes) and ear drum
The inner ear consists of the cochlea, the auditory (hearing) nerve and the brain
Sound waves enter the ear canal and make the ear drum vibrate. This action moves the tiny chain of bones (ossicles – malleus, incus, stapes) in the middle ear. The last bone in this chain ‘knocks’ on the membrane window of the cochlea and makes the fluid in the cochlea move. The fluid movement then triggers a response in the hearing nerve.
Diagram of the human ear
What happens when you have problems with hearing?
When your hearing is working normally, information is being passed through the different parts of the ear to the brain. The type of hearing problem you may have depends on which part of the ear is not responding well.
Outer ear or middle ear problems lead to inefficient transfer of sound. The cochlea is still working but may not receive enough information. This type of hearing loss is called conductive hearing loss. The problem is that the sound is not being conducted (transferred) well enough. Conductive deafness can be caused by things such as an ear infection, a hole in the eardrum or otosclerosis.
An inner ear (cochlear) problem means that sound arrives at the cochlea, but is then not fully passed on to the hearing nerve. Also it is possible that the hearing nerve itself is not passing on information well, or fails to pass on the sound at all. A cochlear or neural hearing loss is called a sensorineural hearing loss. Sensorineural hearing loss can be caused by things such as old age, Ménière’s Disease or loud noise.
It is possible to have a mixed hearing loss with both a conductive and sensorineural element.
If you do, you can probably prevent hearing loss caused by excessive noise or intrusion by foreign objects.
Here is some good advice about preventing hearing loss and tinnitus.
- Be aware of noise in your workplace. The sound level must not exceed 85 dB. If it does, reduce the noise level or wear ear protectors.
- Lower the volume of your television, personal stereo or Walkman. Don’t play them too loudly and take special care if you use headphones. You must also take care when using the car stereo. It is common to turn up the volume in the car because of noise from the engine and the wind.
- Wear ear plugs if you go to rock concerts or night clubs. Take a break so your ears can rest, and do not stand close to loudspeakers.
- Wear headphones if you use noisy equipment such as drills, lawnmowers, etc.
- Do not use cotton wool. It may push wax down onto your eardrum and can increase the production of wax and/or damage the eardrum.
- Do not put fingers or towels in your ears. They can also push wax down onto your eardrum and can damage your skin.
- Unclean water can cause ear infections which may result in hearing impairment.
Cleaning your ears
- Clean your ears with extra care. Wipe the outer ear with a washcloth or tissue. Do not put anything into your ear smaller than your elbow. Do not use Q-tips, bobby pins or sharp pointed objects to clean your ears. These objects may injure the ear canal or eardrum.
- Earwax is the ear’s mechanism for self cleaning. If you have a build-up of wax that is blocking your hearing, see your doctor to have it removed.
- If you experience itching or pain in your ears, consult with your primary care physician to determine the appropriate treatment and to determine if you need to see a specialist.
- If you have pierced ears, clean your earrings and earlobes regularly with rubbing alcohol.
Illness and Medications
- Reduce the risk of ear infections by treating upper respiratory (ears, nose, throat) infections promptly.
- Some illnesses and medical conditions can affect your hearing. If you experience sudden hearing loss or have constant noise in your ears or head, see an ear doctor promptly.
- Drainage from the ear is not normal and usually suggests infection. See your doctor as soon as possible.
- Some medications can affect hearing. Take medications only as directed, and consult your doctor if you experience unusual hearing, balance problems, or ringing in the ears.
- At home or work, wear hearing protection during exposure to loud levels of noise. This includes mowing the lawn, leaf blowing or using power tools. By law, a noisy work environment requires use of hearing protection. Hunting shops and some garden centers carry ear-protecting headgear.
- Ear buds, such as those that come with an IPOD or MP3 player, do not protect your hearing. Also, listening to music while using power tools is dangerous to your hearing and should be avoided.
- When using stereos and home theater systems, avoid high volume levels. If you think it is too loud, it probably is.
- When using personal sound systems, the volume should be at a comfortable level. If someone else can hear what you are listening to, the volume is too high. Remove the headphones from time to time to give your ears a rest.
- Wear earplugs at rock concerts, nightclubs and motor sporting events.
- Keep automobile sound systems at sensible volumes. This can help you avoid hearing damage and allow you to hear and yield to emergency vehicles.
- Always wear a helmet when you bike, ski, and roller blade,on-board or in any other activity that puts you at risk for head and ear injuries.
- If you scuba dive, learn and practice proper underwater techniques to avoid potentially damaging changes in pressure inside your ears.
- When flying in an airplane, swallow and yawn frequently when the plane is ascending and descending to equalize pressure in your ears. If you have an upper respiratory problem such as a cold or sinus infection, take a decongestant a few hours before descending, or use a decongestant spray just prior to descent and on landing.
- Earplugs with special filters can be purchased to help equalize air pressure in ears during air travel.
- Have your ears checked regularly by your primary care physician. Have your hearing checked by an audiologist if you or anyone else questions whether your hearing is normal. Consult an ear physician as necessary.
- When outdoors in sunny weather, remember to use a sunscreen on your ears.
- If you notice unusual bumps or scaly areas on the exterior ear, consult your physician.
- Know the warning signs of hearing loss:
- Difficulty hearing conversations, especially in the presence of background noise
- Frequently asking others to repeat what they have said
- Misunderstanding what other people say and answering inappropriately
- Difficulty hearing on the telephone
- Requiring the television or radio volume to be louder than others in the room prefer
- Feeling that people are mumbling or have marbles in their mouth when they talk
- Difficulty hearing environmental sounds, such as birds chirping
- Agreeing, nodding your head, or smiling during conversations when you are not sure what has been said
- Withdrawing from conversations and social situations because it is too difficult to hear
- Reading lips so you can try to follow what people are saying
- Straining to hear or keep up with conversations
- Noise within your ears or head, called tinnitus, which is not caused by an external sound source
- See an ear doctor immediately if you injure your ears, experience ear pain, or notice changes in your ears or hearing.