Hearing Loss and Deafness

Hearing Loss and Deafness
by Norman J. Harris, MD
Affiliated Ear, Nose and Throat of Orange county
reprinted with permission from www.ocentdoc.com

Language defines us as human. Hearing is how we learn speech. As we learn our language as children, we use that language to organize how we see the world. Hearing is how we best receive the speech sounds that contain the ideas, feelings and personalities of other humans.

If we lose hearing, we lose a bit of of our humanity. The device we call the ear performs the task of translating the analog sound waves in air into digitized nerve impulses in the organ of hearing. The process of hearing involves two principal stages. First, the sound waves traveling in the air are reproduced in the fluids of the cochlear portion of the inner ear. The structures which accomplish this task include the outer ear, the ear passage, and the ear drum and bony chain. The next phase of hearing involves the hair cell array in the organ of Corti of the cochlea, which analyses the waves and converts them into the complex digital code carried by the nerve of hearing to the brain. Additional stages of hearing include the brain which constantly adjusts the cochlea depending on what we intend to hear. Our ears exhibit miraculously sensitivity.

INNER EAR SENSITIVITIES
The conduction mechanism of the first stage, at the threshold of hearing for a 1000 Hz tone moves a distance of 1/10th the diameter of a hydrogen atom. We perceive the movement as sound.

Mode	Lowest Reported Threshold
Auditory	10-4 dyn/cm2 peak sound pressure
Seismic	5 X 10-4 cm/sec2 peak acceleration
Rotational	0.04 deg/sec peak velocity
Gravity	5 cm/sec2 lineal acceleration

Disorders of the ear may affect either or both stages. The two over all types of loss are:

conductive.......caused by problems affecting the first stage of sound processing

nerve loss.........resulting from malfunctions in the second and later stages

Conductive Losses

Conductive losses are caused by anything interfering with the first stage of sound processing. Conductive losses make the sounds seem faint or distant. When the sound source is made louder, the hearing loss is completely overcome. Often the hearing loss is accompanied by a feeling of blockage.

Common causes include:

wax in the outer ear passage
fluid in the middle ear

Other conditions include otosclerosis which jams the bony linkage between the ear drum and the inner ear, or ear drum/bony chain damage from chronic infection.

Conductive losses almost always can be repaired by either medicine, surgery or a combination.

Nerve Hearing Loss

The structures involved in a nerve hearing loss (otherwise called ‘sensorineural’ or ‘perceptive’) include the cochlea and eighth cranial nerve, are locked away inside the bones at the bottom of the skull. The sounds of language are coded in high frequencies and in the low frequencies. When normal hearing people have difficulty hearing speech sounds in the low frequencies, they figure them out from what they hear in the high frequencies. In a noisy background, we count on both.

In addition to affecting the loudness of hearing, nerve hearing loss produces distortion of the sounds entering the ear. Someone with this kind of loss may be aware of sounds, but makes errors deciding exactly what sounds represent. People with a nerve hearing loss experience difficulty decoding the complicated sounds we string together to make speech.

In noisy situations, people with a nerve hearing loss - which almost always affects the high frequencies first - have the greatest difficulty.

Until recently, most of these losses were attributed to "old age". We are now wiser and understand that the tendency to develop these losses probably runs in families and is aggravated by the noise pollution in our society. In fact, the gene for bringing this hearing loss may be located on the chromosome very near the gene for longevity, thus explaining why older people so often have this type of hearing loss. A preventable cause of such loss is work exposure to loud noises. Certain medications, occasionally required in the treatment of life-threatening infections , have been found to damage the hearing nerve.

The person who has this hearing loss usually doesn't know it. The damage usually occurs gradually and since we usually don't know what is going to be said to us, we can only accept what our ears tell us as the truth. When hearing deteriorates to a moderately severe level we finally become aware what our ears are telling us can’t possibly be correct. People who have normal hearing and who know what they and others are saying know that the person with sensorineural loss has lost hearing before they do.

People with a nerve loss have problems communicating with friends and family. Though they hear what is being said, they often hear it incorrectly and having a conversation becomes very difficult. Often, families give up trying to get through to the person who has a nerve loss. It is a rare friend who continues to try. For the person with a nerve hearing loss, a public gathering such as a party or a performance is a disaster. Often the person with a nerve hearing loss begins to avoid going into public without realizing why. The telephone becomes a major source of communications, since it is easier to understand on the telephone than face-to-face at an moderate stage of deterioration. This explains why so many of our senior citizens spend so much time on the telephone speaking to people whom they could probably just as easily visit face-to-face.

Through the next few decades, we don't foresee any readily available surgical or medical treatment for most nerve hearing losses. The best ways to improve communications include:

Controlling the Listening Situation
Amplification Devices

Ear surgeons are watching the new ear implants with great interest.

Wax in the Outer Ear Passage

Otitis Externa

Otitis externa has many different names depending on the stage of the disease. Some call it swimmer's ear. Others refer to a "fungus" in their ears. The most closely related condition anywhere else in the body is eczema.

This condition usually starts when the natural wax barrier in the ear is damaged. Wax is a substance produced by the skin in the outer passage of the ear which protects the ear from moisture and
bacteria. It is not a waste product. Sooner or later, all artificial attempts to remove wax damage the protection of the outer passage of the ear. This is why we are so opposed to using cotton-tipped applicators, hair pins, and other instruments as part of personal hygiene. The wax is formed within the ear and slides out the ear where the movement of the jaw joint crumbles the dried wax and allows it to flake out. Beyond the unsightly wax which appears at the very edge of the ear passage and which can be easily reached with a damp face cloth gently twirled on the finger, there is usually no visible wax in the rest of the ear passage.

The two major enemies of the waxy defense system in the outer ear passage are water and mechanical scratching or rubbing. Once the wax defenses are broken, certain bacteria begin to invade and create an alkaline environment which makes the ear weep and become itchy. Usually, this results in more scratching.

The first symptom of this condition is excess wax formation. This is a natural attempt by the ear to protect itself. Sooner or later, the wax glands become exhausted and the ear is super clean. It also itches. The irresistible urge to rub the ear now sets the ear up to be invaded by bacteria and it becomes moist and swollen. Finally, the repeated cycles of infection make the ear passage scar down and close.

The best way to avoid this disorder and the simplest way to reverse it once it begins is by avoiding anything that wets the ear or touches or rubs the inside of the ear. Wax should be removed only from the outermost edge of the ear passage. Cotton-tipped applicators will only push wax further down into the ear passage where it will accumulate and overload the transportation mechanism. Swimmers need only be sure that their ears are perfectly dry before retiring at night. Ear plugs are not usually necessary. They push the wax further down inside the ear while at the same time providing a surface for the constantly moving ear passage to rub against. The best way to assure that the ear is dry is to use some form of drying drop which usually consists of some sort of mildly acetic substance. (Equal parts of rubbing alcohol and white vinegar can do as a drying drop in a pinch.) A hair dryer works well in drying the ear. Occasionally, oral antibiotics are required to control an acute flare-up. We like to avoid the use of any drops which are available on the market for dissolving ear wax since our experience has been that these drops have difficulty telling where the wax stops and your healthy ear passage begins.

If you find that you have a very hard wax, then a scheduled visit to the doctor is in order. Hydrogen peroxide is too watery to use more than rarely and should be used with specific doctor's instructions. It is helpful to use a few drops of mineral oil or baby oil at bedtime the night before the visit.

[return ]

Fluid in the ear (Middle Ear Ventilation Problems)

The ear passage is a tunnel at whose end is a thin wall called the ear drum. On the other side of that ear drum is a space called the middle ear which normally contains air. The air gets there through a tube called the eustachian tube, which is normally closed, and which opens during yawning or swallowing , often causing a clicking sound. When the tube stops functioning, a vacuum develops in the ear. Nature responds to the vacuum by secreting fluid. The fluid may be as thin as water or so thick that we occasionally call it a glue ear. The degree of hearing loss caused by fluid varies.. Occasionally, when there is a vacuum in the ear, the ear drum will be sucked in. When vacuum persists for years, chronic infection, damage to bone, or perforations of the ear drum may result.

The tube that lets air into the ear is partially made out of gristle (cartilage). In children, this cartilage is very soft and when a small vacuum develops in the ear, it tends to collapse the cartilage in the same way that a wet straw collapses when you try to drink through it. The cartilage firms up with maturity. Heredity seems to determine the mechanics of the muscles that serve to pull the tube open. Finally, there is a membrane factor, referred to as "allergy" which is poorly understood, but is operating at a biochemical level. Children’s adenoids are said to have some mechanical affect on the way the tube opens, but their role in the this process in quite unclear at this time.

Ear ventilation problems generally begin at about nine months of age, and gradually get worse until about six to eight years. By puberty the ears improve, and most chronic ear ventilation problems have almost always vanished. In adults, the tubes malfunction during inflammatory conditions like infection or allergy. Those predisposed to such problems will experience the most difficulty when challenged by environmental pressure changes, such as flying or SCUBA diving.

Treatment varies. Decongestants are frequently offered to improve a borderline tube. Adenoidectomy is said to improve the mechanics of the eustachian tube opening. Artificial middle ear ventilating tubes break the vacuum in the ear responsible for the complications. Ear ventilating tubes mimic the solution nature sometimes uses...a hole in the ear drum. As long as the hole, natural or artificial, is kept perfectly dry, the ear will rarely get infected. Artificial tubes usually last about nine months, though the range can be from two weeks to two years!

[return ]

Hearing Better Without Hearing Aids

Because of the nature of human hearing, the most important signals that we concentrate on in the course of our daily life are speech signals. They are complex codes. Each speech sound (phoneme) can be thought of as a little sonic jigsaw puzzle with pieces in the high frequencies, and pieces in the low frequencies. We need a minimum number of pieces in each puzzle in order to figure out which sound it is. When the number of pieces falls to a critical level,
our brain automatically guesses, sometimes incorrectly.

In order to compensate for the pieces of the puzzles that are missing in what we hear, we automatically search the speaker's face for clues. This is not something that we need to learn; it’s automatic. Detecting elements of the puzzle is far more difficult when there is noise in the background. Hearing impaired persons should make the most of their available hearing and visual cues, and minimize background noise as much as is practical. Remember: your eyes will
help you hear.

A hearing impaired person, because of the automatic use of eyes, not only responds differently in the eyes of those around him, but also carries him/herself differently. Be aware of the differences. Use them to your advantage.

Don’t Talk To Anybody You Can’t See...
Ask everyone at home to remember that you need to see them in order to understand them. Conversations, particularly heated conversations, should take place in a quiet well lit room where you can be face to face. The kitchen is usually the ideal place.

Survey your sitting room. See whether or not the furniture might be arranged in such a way that nobody can pop into a chair where you cannot see them. Increase the lighting in the room, and make sure there is more lighting on the other people than there is on you.

When you can't find something in the house, don't shout "where is it" unless the person who answers is where you can see them. If you take this simple precaution, you will prevent saving the annoying "what" when they do answer.

In a restaurant, avoid seating in a booth. A booth is usually dark, noisy and someone is usually sitting beside you. Each represents the worst possible listening situation for you. Instead, ask the maitre d' to seat you in the center of the room "where the service is better" and also where the tables are square, and you will be able to see everyone at the table. Business lunches, for you, should concentrate on lunch, not on business. You don't do well in these settings and serious negotiations should be reserved for a more controlled environment.

In the office setting, arrange the furniture so that nobody can sit where you can't see them. Try to arrange appointments so that you are dealing with people on a one at a time basis, and be sure that the light is behind you - on them, and not the reverse. If you have a choice, select small group meetings, preferably at round tables so that you can see everyone at the table. If you are in a negotiating situation, try to sit opposite the most important person on the other side, so you can gather the maximum number of visual clues. In all meetings, be a strong proponent of Robert's Rules of Order. Portray this as a means of facilitating decisions, but in fact use it as a strategy to be sure that only one person at a time is speaking.

Talk First In A Crowd...
In the hallway and in crowds, become the greeter. If you don't try, by the time you figure out who did or did not say hello to you, they are gone, wondering why you have become so distant. On the other hand, don't stop to chat in a crowd. The noise will put you at a disadvantage. The rule is to say "hello" and keep moving. Invite them to call you for a nice private chat later on, of course, one to one.

Don't talk standing up. This increases the chance that the other person will turn away. When there is something important to discuss, try and maneuver the conversation to a setting in which you can be seated, of course, face to face.

Body Language...
When you meet somebody, particularly when you are a man greeting a woman or a child for the first time, remember to break eye contact. Your adaptation to your loss often appears as a penetrating stare. This is vaguely intimidating to people smaller than you are, and may make them uneasy with you. The phrase in our language is "eyeball to eyeball". Remember to break eye contact from time to time.

Only Your Friends Will Tell You...
Listen to those closest to you who tell you how much you are missing. Remember the old chestnut about everyone who is not here, "raise your hand". You can't possibly know who is avoiding you because the punch line at a joke spoils the fun of the teller of the joke. You don't want to be dropped from anybody's joke list - or any other list - because you are hard to get through to.

[return ]

Hearing Aids

It used to be said nerve hearing losses could not be helped by hearing aids. While this may have been true several years ago, it is no longer true today. No one who has such a hearing loss should deny himself the opportunity to be fitted with a hearing aid, provided the fitting is accomplished by a properly trained individual who either is an audiologist, or who is under direct supervision of such a person. The major objection ot hearing aids is how they look. It is our feeling that it looks much worse to be constantly saying "what ?" than to be wearing a behind-the-ear hearing aid. You should be aware that we are beginning to realize that many hearing losses are best fitted with two hearing aids to give balanced hearing. This is a subject which is best discussed with the person who dispenses the hearing aid

Certainly, anyone with such a hearing loss should discipline themselves to avoid those situations which we know will make the nerve loss worse. Noisy occupations and hobbies should be avoided wherever possible. If it is not possible to avoid noisy situations, then the use of ear protection devices should be discussed with the physician or audiologist. Whenever a new medication is prescribed, it is prudent to remind the physician that there is already a hearing loss so that he can be sure to avoid known hearing toxic drugs if the clinical situation permits him to.

[return ]