The ear is divided into three parts; the external ear, middle ear and inner ear. Each part performs an important function in hearing and/or maintenance of balance.
Sound waves pass through the ear canal of the external ear and vibrate the tympanic membrane (ear drum). The tympanic membrane separates the external and middle ear. There are three small bones of hearing (hammer or malleus, anvil or incus, stirrup or stapes) in the middle ear which act as a transformer to transmit the energy of sound vibrations to the inner ear fluids. The inner ear (labyrinth) contains two fluid systems, one suspended inside the other, separated by a thin membrane. This system contains a delicately balanced fluid which bathes nerve endings responsible for hearing and balance. The nerve endings generate electrical impulses in the hearing center (cochlea) which are then transmitted through the hearing nerve to the brain where they are interpreted as sound. Movement of fluid in the balance portion of the inner ear (vestibule and semicircular canals) results in electrical impulses which are sent through the balance nerve to the brain where they are interpreted as motion. The inner ear senses posture, rotation, acceleration and deceleration.
Balance is the ability to maintain one's equilibrium and is maintained by the interaction and coordination of impulses received from the inner ear, visual system and proprioceptive system.
The inner ear, as discussed previously, is a fluid system. Movement of fluid results in electrical impulses which are sent through the balance nerve to the brain where they are interpreted as motion.
Vision is responsible for giving accurate information about one's surroundings. It is estimated that 90% of information received by the brain is through the eyes. If you look about and everything is vertical, you feel well. However, if you are in a funhouse where everything is on a slant, you may feel dizzy even if you are standing still.
The proprioceptive system is made up of the muscles, joints and tendons in the arms and legs and is responsible for giving information to the brain regarding movement and body position. This system enables you to walk down steps without looking where to place your feet.
Dizziness is a symptom, not a disease. It is defined as a disorientation in space, a sense of unsteadiness, a feeling of movement within the head such as giddiness, swimming sensation, lightheadedness or a whirling sensation known as true vertigo. Dizziness can result from disturbances in the inner ear, brain eyes, neck, muscles and joints, or a combination of these systems. Since the mechanism of maintaining balance is so complex, it is in many instances impossible to find out the exact cause of the dizziness.
To evaluate the symptom of dizziness a complete medical history, audiogram (hearing test) and electronystagmogram (ENG or balance test) are generally needed. In some instances, a CAT scan (x-ray) and blood work are also needed.
The medical history is perhaps the most important part of the evaluation. The physician needs to know what the patient feels like when he is dizzy, the duration of symptoms, what triggers or relieves the symptoms and whether auditory symptoms (hearing loss, ear pressure or tinnitus) are present.
An audiogram documents the present level of hearing. The ENG gives objective information as to how the inner ear balance mechanism is functioning. A CAT scan is obtained when nerve hearing loss is worse in one ear to rule out the possibility of a benign tumor on the hearing nerve. Blood tests, such as blood sugar, body fats (cholesterol and triglycerides), thyroid, a potential blood infection or autoimmune process (a process in which the inner ear makes antibodies against the ear) may be ordered. These blood abnormalities can result in a feeling of dizziness and with proper treatment the feeling of dizziness may decrease.
Our sense of balance comes from three sources; the eye, the inner ear, and kinesthetic senses. When one source disagrees with the others we sense dizziness. Any disturbance in the inner ear or its central connections may cause a feeling of dizziness with or without auditory symptoms (hearing loss or tinnitus). If no other cause can be found, the inner ear is often thought to be the source of the problem.
The inner ear usually produces symptoms of a whirling sensation known as vertigo or a feeling of imbalance. Symptoms are usually episodic, that is, they come and go. Less often they produce a constant sensation of dizziness. Many times dizziness is associated with hearing loss, ear pressure and tinnitus (head noise).
The following is a discussion of the most common forms of dizziness caused by the ear.
See information sheet on Meniere's Disease.
This is one of the most common forms of dizziness caused by the inner ear. Symptoms are believed to be caused by the fragmentation of a small calcium deposit (otolith) in the inner ear. These fragments float freely in the inner ear fluid until a change of gravity causes them to impinge on nerve endings causing a sensation of dizziness. This can occur spontaneously, follow a viral illness, or result from head trauma.
The symptoms associated with this condition are a spinning sensation or lightheadedness, sometimes associated with nausea, which are brought on by changes in head and body position. The symptoms are of short duration, lasting seconds to minutes. The ear toward the floor when symptoms occur is usually the offending ear. There are no auditory symptoms (hearing loss, ear pressure or tinnitus) associated with this condition.
This condition is called benign because it is self-limited, that is, it will improve on its own. Recovery takes several weeks or months, occasionally up to one year.
Treatment is only for symptomatic relief by using vestibular suppressant medications such as Antivert or Valium. Rarely is surgery required.
As a person grows older, certain changes normally occur, such as a change in hair color and a decrease in the ability to hear. Just as these changes occur, there are also changes occurring in systems which are needed to maintain balance.
The following is a discussion of the changes that occur, symptoms one may experience and suggestions to help minimize these symptoms. By following these suggestions, sometimes an examination may be avoided. Although the examinations do provide peace of mind, they may be expensive.
Just as the hearing portion of the inner ear loses its sensitivity to sound resulting in a hearing loss, the balance portion may lose its sensitivity to rotation, acceleration and deceleration. This change consists of either a decrease in impulses originating in the inner ear or a decrease in the brain's ability to interpret these impulses; but in either case, the brain interprets this change as dizziness.
An additional symptom is a gradual decrease in eye sight and blurred vision or eye fatigue when doing close work. This is caused by a decrease in the elasticity of the lens of the eye and is correctable by wearing bifocals. Other conditions, such as glaucoma or cataracts may also cause a decrease in vision and thereby decrease the amount of information the brain receives.
Finally, there are changes in the proprioceptive system (nerve endings in the muscles, tendons and joints in the arms and legs) due to aging. There may be exaggerated curvatures of the spine or a decrease in muscle mass causing generalized muscular weakness. Conditions such as diabetes or arthritis may cause a decrease in feeling in the extremities, thus decreasing information the brain receives regarding body position and movement.
There are no medications that will alleviate age-related symptoms, but there are ways to help minimize them. The following are suggestions we give to our patients who have dizziness due to aging.
There is a Chronic Ear Disease Support Group located in the Metro area. If you would like to talk to someone you can call 339-2120.
MM Nurse Manager ENT Clinic
Cleveland Clinic Foundation, "Inner Ear Dizziness"
Bellanger, John. "Diseases of the Nose, Throat, Ear, Head and Neck", 1985.
Paparella and Shumrick, "Otolaryngology", Volume Two - Ear. 1973
Merck Manual of Diagnosis and Therapy. Fourteenth Edition