How the Ear Works
Sound waves are gathered add funneled into the ear canal by the pinna toward the eardrum. The vibrations of the eardrum are transmitted through the three bones in the middle ear, malleus (hammer), incus (anvil), and stapes (stirrup) to the cochlea or inner ear. The stapes vibration causes fluid within the cochlea to move stimulating the release of electrical energy from tiny nerve endings called hair cells. These signals travel to the brain and we perceive sound.
Hearing Loss-As can be deduced from the discussion of the function of the normal ear, there are several problems that can result in hearing loss. These problems are generally divided into two types. A conductive hearing loss is a problem with the conduction of sound from the outside to the inner ear. A sensori-neural hearing loss is due to a disturbance of the nerve endings in the inner ear itself or in the hearing nerve. A mixed hearing loss consists of hearing loss from both a conductive component and a sensori-neural component. Depending on the type of hearing loss that you have, surgery or a hearing aid may be recommended to correct your hearing loss. In circumstances of extreme hearing loss, a cochlear implant may be recommended.
The Hearing Test
The hearing test consists of several different measurements. Each ear is measured in its ability to detect different frequencies, or “pitches” or tones, that the human ear is commonly exposed to. A volume is recorded for each tone and this is placed on a grid. In addition to these measurements, the ear’s ability to understand speech is measured. This measurement is taken by giving words presented at a sound level much greater than the ability to detect speech. It is useful to use an old radio as an example. The first test to detect volume is much like turning the volume up and down on the radio. The second test to measure understanding is much like turning the dial to the frequency that the radio station broadcasts. The person will not hear very well if the speech understanding or discrimination score is low, no matter how high the volume is. This is much as if you turn a radio up very loud but it is off the station.
Types of Conductive Hearing Loss
The simplest form of conductive hearing loss is experienced by all. When one has gone swimming or takes a shower and has water in the ear, it produces a small conductive hearing loss which feels as if the ear is dull or plugged. This is quickly reversed when the water is gone. Conductive hearing loss also occurs when wax plugs the ear. Another form of conductive hearing loss occurs in persons who develop a fluid collection in the middle ear. Children often develop this problem. A disturbance in the conduction of the eardrum with the small ear bones can also cause hearing loss, but this can be corrected with surgery.
Types of Sensori-Neural Hearing Loss
There are many different things that can affect the inner ear and the hearing nerve. We all lose some of the hearing in the inner ear as we get older. This usually catches up to us in the speech range in our 60’s. This causes a high tone nerve hearing loss. Persons with a loss primarily in the high tones will have difficulty in hearing the consonant sounds. They will still hear the vowel sound well because these are low tones. The result is that it sounds as if people are mumbling when they talk. One hears every word that is spoken because every word contains a vowel sound. However, they miss the consonant sounds that give meaning to words. An example is related in the words ten, pin and in. A person with high tone nerve hearing loss may miss the “t” in ten or the “p” in pin, and each of these words sounds like “in”. Often, the person is able to put the word in context with what is being spoken and can figure out which consonant was used. For example, a person would not say, “I stuck him with a ten.” In this case, one could determine that the person meant “pin” even if all you heard was “in”. This type of hearing loss can be very confusing and lead to sore feelings. Your spouse may say “She hears what she wants to hear. I was across the room and she heard me”. In fact, you heard the vowel sound in the words (low tones) as well as he did. However, not hearing the consonant sounds (high tones) made his speech indecipherable. You may find yourself tired and irritable at the end of the day because you’ve been working hard to put this complicated puzzle together all day. It can even make one feel depressed and lead to reclusive behaviors. Another type of nerve hearing loss is due to inner ear fluid imbalance known as cochlear hydrops. This can cause a fluctuating hearing loss with ringing in the ear. This is usually treated with a low -4 – salt diet. Often, a fluid pill is given in treatment for this. Many patients who have this condition also notice problems with dizziness, as this problem also can affect the balance portion of the inner ear. There are many types of nerve hearing loss that are inherited and passed from on from family to family. Sometimes, this hearing loss is associated with other inheritable abnormalities. Very rarely, about one in one hundred thousand persons will experience hearing loss in one ear due to a tumor growing on the hearing nerve. If it is felt there is enough degree of suspicion to warrant it, further tests may be needed to eliminate this as a possible cause of your hearing loss.
Hearing Loss In One Ear
Those with hearing loss in one ear get along very well in general. However, there are certain things that are very difficult for those that hear well in only one ear. Primarily, this person will have a very difficult time telling where sound is coming from. Sound travels at a relatively low speed, and sound coming from one side hits the closest ear a split second before it hits the other ear. The brain uses this difference in time to locate where sound is coming from. It also sounds louder in one ear than the other. This ability is lost when one hears in only one ear. Hearing loss in one ear also causes difficulty hearing in situations with background noise. That same ability of the brain to determine sounds hitting one ear a little faster than the other allows us to use our two ears to focus on one sound out of a crowd of sounds. This is lost with hearing impairment in one ear. Those with hearing loss in one ear should be very careful crossing a street, and check to make sure no cars are coming. In difficult listening situations, such as parties, they should position themselves such that their good ear is toward those they are speaking with and their bad ear is toward a wall, so that no one will come up on the other side and start talking to them, unaware of their hearing loss. In some instances, the use of a CROS hearing aid is desirable. This stands for contralateral routing of signals. This hearing aid takes sound from one side and transmits it to the other ear via a radio signal. It is not useful for a lot of people. Those that work in situations with co-workers on either side are especially pleased with this device. Another device that is helpful in unilateral hearing loss is a bone anchored hearing aid. These devices involve the implantation of a titanium screw in the skull and a processor on the outside that attaches directly or via a magnet couple. The sound waves are transmitted through the skull to the cochlea of the opposite ear. A headband that presses the processor onto the head can be demonstrated to give you a close simulation of how the actual process can work for you.
Recommendations For Friends and Relatives of Those With Hearing Loss
Get the person’s attention before you speak. It is very important to touch the person or make sure they are aware you are talking before you start your conversation. You definitely do not want to try to start a conversation from another room.
Speak at a normal volume and normal rate
It is distracting and confusing for a person with a hearing loss to have someone speak at a loud volume in an abnormal way and at a fast rate. Although you certainly want to speak up and make sure they do hear you, overly loud voices cause distortion and poor understanding. They will often think that they have turned their hearing aid up too loud and will try to adjust it and this will cause problems. Place yourself in front of the person with your lips clearly visible Those with hearing loss often use visual cues from the lips to help understand; therefore, it is very important that they can see you speaking. Along these lines, it is rude and problematic if you are chewing gum or eating while you try to speak. It is helpful for males to avoid mustaches and beards if they have a close family member that has a hearing impairment. The mustache and beard mask some of the lip movements that are helpful in understanding speech. Try to carry on your conversation in a quiet room Competing background noise makes hearing very difficult. We have all experienced this is restaurants and other busy places. This is especially difficult for those with hearing impairment.
Repeat the statement
Repeated statements of the same fact tend to reinforce a hearing-impaired person’s perception of the conversation. It is better to repeat phrases using different words. An example would be as follows: “I want you to go to the store with me.” This sentence could be rephrased as follows: “Let’s go to the grocery.” By repeating the same sentence using a different phrase and words, it might be easier for that person to understand. Repeating the same sentence louder might not be helpful.
Speech Reading
We all use facial expressions, lip movements, and gestures to help us understand speech. Those with hearing impairment rely on this to a greater extent. This is recognizable in watching a movie in which the sound is not coordinated with the action. We have all seen movies in which the actor’s lip movements lagged behind the sound for a second. This is very annoying and distracting. The reason it is annoying and distracting is because we subconsciously rely on visual cues from the lips to help us understand speech. This is why it is important for us to always get in front of another person that is speaking to us so we can see their lip movements. Let the person understand that it is important that we see them when we speak with them. Nevertheless, speech reading has limitations. Obviously, on the telephone this is useless. Also, however, there are many sounds that “look” the same. About two-thirds of all the sounds in the -6 – English language are not visible through lip reading. It is also helpful to use inflections and pauses in speech for meaning. Placing emphasis on different words carries a totally different meaning in the conversation. There are many ways to help develop your skills at speech reading, including watching television with the sound turned down very low to look for speech cues on the lips of the actors. Also, there are many books and videos available that teach lip reading.