DIFFERENT TYPES OF HEARING LOSS
Tinnitus is an abnormal perception of a sound, which is reported by patients as being unrelated to an external source of stimulation. Tinnitus is a symptom, much like a headache, pain, temperature, hearing loss, or vertigo. With tinnitus, the reported distress is usually subjective and difficult to record and appreciate by others. Tinnitus will not cause you to go deaf, and statistically, 50 percent of patients may express that their tinnitus decreases or is hardly perceptible as time passes.
The quality of the tinnitus refers to the description by the patient of the tinnitus. It may be a ringing, buzzing, cricket, ocean, or other type of sound. Also, the quality may be multiple sounds or a singular sound. Tinnitus is a very common disorder, and may be:
- Intermittent, constant, or fluctuating
- Mild or severe
- Varied in nature, from a low roaring sensation to a high-pitched type of sound
- Associated with a hearing loss
TYPES OF TINNITUS
Tinnitus is also classified further into subjective or objective types.
- Subjective tinnitus – This is a noise perceived by the patient alone and is quite common.
- Objective tinnitus – This is a noise perceived by the patient as well as by another listener. This form of tinnitus is relatively uncommon, and the location of tinnitus may be in the ear(s) and/or in the head.
TINNITUS IS A SYMPTOM
Tinnitus is a symptom of neurologic disease. It may occur with a hearing loss, vertigo, or pressure symptoms in the ear or it may occur alone. This condition must always be thought of as a symptom and not a disease, just as pain in the arm or leg is a symptom and not a disease.
Because the function of the auditory (hearing) nerve is to carry sound, when it is irritated from any cause, it produces head noise. This phenomenon is similar to the sensation nerves elsewhere. If one pinches the skin, it hurts because the nerves stimulated carry pain sensation.
Tinnitus may be produced in one or more locations, called the site of lesion. The cause of tinnitus may be one or many.
- Peripheral site lesion – One located on the auditory nerve or cochlea, and includes dysfunction established within the auditory system that extends up to, but not involving, the brainstem.
- Central site of lesion – This refers to involvement of the central auditory pathways, beginning at the brainstem and involving other portions of the central nervous system.
Tinnitus may originate from various lesions and from different sites. The auditory system involves highly complicated inner ear structures, many nerve pathways, and a great amount of nuclei that form a complex neural network. Pinpointing the cause of tinnitus to a certain structure becomes questionable.
This is demonstrated by patients who have had unyielding tinnitus after having surgery on their ear or incurring severe diseases of the ear. In an attempt to relieve the tinnitus, cutting the auditory nerve is often done. When the tinnitus is persistent, this indicates that the site of lesion causing the tinnitus likely shifted into the central nervous system.
There are many other causes related to the ear which would result in tinnitus. These include:
- Abnormal neural activity – Tinnitus could be explained by abnormal neural activity in the auditory nerve fibers, which may occur if there is a partial breakdown of the myelin covering of individual fibers. A defect in the hair cell would trigger the discharge of connected nerve fibers.
- Chronic cochlear disorders – There may be increased spontaneous activity in the hair cells and neurons, resulting in tinnitus. There are two different kinds of afferent fibers in the auditory nerve: inner hair cell fibers with large diameters and outer hair cells fibers with small diameters. Thus, loss of signals from the cochlea might trigger tinnitus as a manifestation of a functional imbalance between the two sets of fibers. In addition, other abnormal changes of the cochlear fluids may result in tinnitus.
- Medications – There are some drugs which will cause tinnitus, such as excessive aspirin intake. If you have tinnitus and are on medication, you should discuss the symptom of tinnitus with your physician. In many instances, once the drug is discontinued, the tinnitus will no longer be present.
- Ear wax – Cerumen, known as simple ear wax, in the ear canal.
- Otosclerosis – This is a fixation of the stapes bone in the middle ear.
- Meniere’s disease – A complex syndrome involving hearing loss and vertigo.
- Sudden trauma – A direct blow to the ear or head.
- Injury – This causes damage to the inner ear such as exposure to excessively loud sounds.
- Tumors – On the hearing nerve or other problems in the brainstem or central nervous system.
- Other vascular abnormalities – These can occur in the skull or base of the skull.
A complete cochleovestibular evaluation is necessary in all patients with severe, disabling tinnitus. The test battery used is an attempt to establish the site of lesion and to rule out any significant pathology which may require further treatment.
One diagnostic test for tinnitus is frequency testing. Since tinnitus is often high pitched, frequency judgments in this region normally are poor. Frequency discrimination up to approximately 16,000 Hz (in the upper limit of hearing) is far less exacting than the middle-frequency region. In addition, patients suffering from high-pitched tinnitus often have a high-frequency hearing loss, which may impair frequency discrimination. Therefore, test-retest reliability in matching the frequencies of audiometer tones to the pitch of tinnitus may be poor.
The audiologist will attempt to do pitch-matching and loudness-matching when other forms of diagnostic tests fail. In addition, an attempt may be made to determine the maskability of the tinnitus, which is unrelated to its loudness. Also, a determination of residual inhibition can be made when tinnitus is temporarily reduced after a masking sound has been turned off, and the reduction is termed “residual inhibition.”
TREATMENT OF TINNITUS
Generally, most patients will not need any medical treatment for their tinnitus. For patients who are greatly bothered by tinnitus, they may use masking techniques and other treatments, such as:
- Listening to a fan or radio – This generally is more advantageous if one is attempting to go to sleep.
- A tinnitus masker – This device is a small electronic instrument built into a hearing aid case. It generates a noise which prevents the wearer from hearing his own head noise. The masker is based on the principle that most individuals with tinnitus can better tolerate outside noise than they can their own inner head noise.
- Biofeedback training – This is effective in reducing tinnitus in some patients. It consists of exercises the patient learns in order to control various parts of the body and relax the muscles. When a patient is able to accomplish this type of relaxation, tinnitus generally subsides. Most patients have expressed that the biofeedback offers them better coping skills.
- Avoidance – This includes making every attempt to avoid anxiety, as anxiety increases tinnitus. A person with tinnitus should avoid losing sleep and becoming fatigued, because, generally, patients who are tired seem to notice their tinnitus more. Also, the use of nerve stimulants is to be avoided, as excessive amounts of coffee and smoking contribute to the head noise.
- Medications – There are some medications utilized to suppress tinnitus. Some patients benefit with these drugs, and others do not. Each patient has an individual response to medication, and what works for one patient will not always work for others. Some of these medications have been proven, however, to decrease the intensity of the tinnitus and make it much less noticeable to the patient. There is, however, no drug anywhere which will eliminate tinnitus completely and forever.