Preventing Hearing Loss

1. Preventing Hearing Loss

2. Anatomy of the Ear • Outer ear - includes the part you can see. Its shape helps to collect sound waves. A tube leads inward to the eardrum. • Middle ear - separated from the outer ear by the eardrum. The middle ear contains three tiny bones called the malleus (hammer bone), the incus (anvil bone) and the stapes (stirrup bone). These bones amplify the movement of the eardrum produced by sound waves. The Eustachian tube attaches the middle ear to the back of the throat and helps to equalize air pressure. • Inner ear - sound waves are picked up by a little spiral-shaped organ called the cochlear. Hairs on the cochlear sense the vibration and pass the message - interpreted into electrical impulses - on to the brain via the cochlear nerve.

3. Types of Hearing Loss • Sensori neural hearing loss • Conductive hearing loss

4. Types of Hearing LossSENORI NEURAL • Sensori neural hearing loss is the result of damage to the inner ear and accounts for over 90% of hearing loss in adults. This type of hearing loss is generally permanent. • Sensori neural hearing loss is irreversible and unnecessary is caused by loud, sudden noises and are more damaging to hearing than regular and extended exposure to loud sounds over a period of time.

5. Causes of Hearing LossSENORI NEURAL • Deterioration of hair cells due to exposure to loud sounds or aging • Deterioration of nerves pathways that transmit signals to the brain, most commonly caused by a tumor pinching the nerves • Trauma to the head • Infection that reaches the inner ear • Heredity

6. Two Types of Hearing Loss Sensori neural loss

7. Types of Hearing LossCONDUCTIVE • Conductive hearing loss occurs when there is damage or blockage in the outer or middle ear, preventing sound from traveling normally through the ear canal to the inner ear. This type of hearing loss can often be corrected.

8. Causes of Hearing LossCONDUCTIVE • Fluid build up, often due to ear infection • Ear wax • Perforated ear drum

9. Two Types of Hearing Loss Conductive loss

10. Factors That Affect Both Types • Type of Noise – continuous, intermittent, impact, high or low frequency • Intensity of Noise – level of loudness • Duration of Exposure – length of time subjected to noise, and over time how often subjected to noise • Type of Noise Environment – enclosed, open, reflective surfaces • Distance from Ears to the Source of Noise

11. Factors That Affect Both Types • Physical position/posture relative to the noise source • Age of listener • Individual Susceptibility • General Health of listener • Number of other Exposures to Noise – at home, in the workplace, during recreational/leisure activities, etc.

12. Ear Disorders • Tinnitus - noises or ringing in the ears or head • Meniere's disease - symptoms may include vertigo (dizziness), tinnitus, hearing loss and nausea • Acoustic Neuroma - tumors on the acoustic nerve.

13. Noise Exposure • Excessive noise levels over a long period of time will damage your hearing so gradually and painlessly that you may not notice the minor deterioration from one day to the next. The parts of the ear that process high frequency sounds are usually the first to be affected. The degree of loss depends on the loudness of the noise and your level of exposure.

14. Noise Exposure • Sudden explosive sounds, such as gunshots, can cause immediate damage. Some people exposed to excessive noise develop tinnitus, which is described as a constant ringing sound. For most cases of noise-induced hearing loss, there is no cure. Hearing aids only amplify sounds, and can't replace normal hearing.

15. Noise Exposure Apart from damage to hearing, exposure to constant and excessive noise can cause other health problems, including: • Headache • Elevated blood pressure • Fatigue • Irritability • Digestive disorders • Increased susceptibility to colds and other minor infections

16. Sample Sound Levels • Normal conversation - 60 dB • Ringing telephone - 80 dB • Hair dryer; power lawnmower - 90 dB • Belt sander - 93 dB • Tractor - 96 dB • Hand drill - 98 dB • Impact wrench - 103 dB • Bulldozer; spray painter - 105 dB

17. Sample Sound Levels • Continuous miner - 108 dB • Chain saw - 110 dB • Hammer drill - 114 dB • Pneumatic percussion drill - 119 dB • Ambulance siren - 120 dB • 12-gauge shotgun - 165 dB • Rocket launch - 180 dB

18. Causes of Hearing Loss • Hereditary disorders - some types of deafness are hereditary, which means parents pass on flawed genes to their children. In most cases, hereditary deafness is caused by malformations of the inner ear. • Genetic disorders - genetic mutations may happen at conception

19. Causes of Hearing Loss • Prenatal exposure to disease - a baby will be born deaf or with hearing problems if they are exposed to certain diseases, including rubella (German measles), influenza and mumps. Other factors that are thought to cause congenital deafness include exposure to methyl mercury and drugs such as quinine. • Noise - loud noises (such as gun shots, firecrackers, explosions and rock concerts) can damage the delicate mechanisms inside the ear. If you are standing next to someone, yet have to shout to be heard, you can be sure that the noise is loud enough to be damaging your ears.

20. Causes of Hearing Loss • Trauma - such as perforation of the eardrum, fractured skull or changes in air pressure (barotrauma). • Disease - certain diseases can cause deafness including meningitis, mumps, and chicken pox. A severe case of jaundice is also known to cause deafness. • Other causes - other causes of deafness include Meniere's disease and exposure to certain chemicals.

21. Age Related Loss • Our hearing gradually becomes less acute as we age. This is normal, and rarely leads to deafness. Age-related hearing loss (presbycusis) typically begins with the loss of higher frequencies, so that certain speech sounds - such as 's', 'f' and 't' - end up sounding very similar. This means the older person can hear, but not always understand. For example, the words 'see' and 'tea' might sound the same.

22. Severity of Hearing Loss • Mild (21-45dB) - soft sounds may be difficult to distinguish. • Moderate (46-60dB) - conversational speech is hard to hear, especially if there is background noise (such as a television or radio). • Moderately severe (61-75dB) - it is very difficult to hear ordinary speech. • Severe (76-90dB) - conversational speech can't be heard. • Profound (91dB) - almost all sounds are inaudible. Most people with profound hearing loss benefit from a hearing aid, while some don't.

23. Causes of Temporary Deafness • Wax - the ear canal secretes a waxy substance that helps to protect and lubricate the tissues. A build-up of wax can block the ear canal, leading to short term conductive deafness. • Foreign object - similarly to ear wax, a foreign object stuck inside the ear canal (such as the tip of a cotton bud) can temporarily cause hearing loss. • Excess mucus - the common cold, a bout of flu, hay fever or other allergies can cause an excess of mucus that may block the Eustachian tubes of the ear. • Ear infections - including infections of the outer ear and infections of the middle ear where fluid and pus don't allow the full conduction of sound. • Drugs - certain drugs, including aminoglycosides and chloroquine, can cause temporary deafness in susceptible people.

24. Deafness • The ear is our organ of hearing. At around 20 years of age, our hearing starts a gradual decline. Higher frequencies are usually the first to go. This age-related hearing loss is normal and doesn't lead to total loss of hearing. Deafness can range from mild to profound and is caused by many different events including injury, disease and genetic defects. There are various ways to categorize deafness. The two main types of deafness are conductive deafness and nerve deafness. Deafness at birth is known as congenital deafness, while deafness that occurs after birth is called adventitious deafness. The most common cause of adventitious deafness is noise, which accounts for over one quarter of people affected by hearing loss.

25. Deafness • Conductive deafness is caused by the failure of the three tiny bones inside the middle ear to pass along sound waves to the inner ear. Another common cause of conductive deafness is the failure of the eardrum to vibrate in response to sound waves. A build-up of fluid in the ear canal, for example, could dampen the movement of the eardrum. In many cases, treatment is available for conductive deafness and normal hearing will return.

26. Deafness • Nerve deafness is caused by disease, trauma or some other disruptive event targeting the cochlear nerve. The rest of the ear - including the tiny bones and eardrum - may be working, but the electrical impulses aren't able to reach the brain. In other cases, the problem is in the brain itself, which can't 'translate' the messages from the cochlear nerve. Most cases of nerve deafness don't respond to treatment.