Search the Site

 
Texas Neurosciences Institute - Methodist Healthcare - San Antonio, Texas
Ear & Hearing
A Discussion of Dizziness

Dizziness is a symptom, which may be defined as a sensation of unsteadiness or imbalance, a disorientation in relation to an individual’s surroundings. The symptom of dizziness may vary widely from person to person and be caused by many different diseases. It varies from a mild unsteadiness to a severe whirling sensation known as vertigo. Because there is little representation of the balance system in the conscious mind, it is not unusual for it to be difficult for patients to describe their symptom of dizziness to the physician. In addition, because the symptom of dizziness varies so widely from patient to patient and may be caused by many different diseases, the physician commonly requires extensive testing to be able to provide the patient with some knowledge about the cause of their dizziness. This booklet is designed to provide the patient with information regarding possible causes of dizziness and their treatment.

Function of the Normal Ear

The ear is divided into three parts: external ear, middle ear, and inner ear.

The external ear structures gather sound and direct it toward the eardrum. The middle ear chamber consists of an eardrum and three small bones. These structures transmit sound vibrations to the inner ear fluid.

The inner ear chamber (labyrinth) is encased in bone and filled with fluid (endolymph and perilymph). This fluid bathers the delicate nerve endings of the hearing and the balance mechanism. This fluid bathes the delicate nerve endings of the hearing and the balance mechanism. Fluid waves in the hearing chamber (cochlea) stimulate the hearing nerve endings which generate an electrical impulse. These impulses are transmitted to the brain for interpretation as sound. Movement of fluid in the balance chambers (vestibule and three semicircular canals) also stimulates nerve endings and sends impulses which are interpreted in the brain as motion.

Maintenance of Balance

The balance mechanisms in the inner ear are one of the main sources of input for the central nervous system, although the eyes, the neck muscles, and the muscles and joints in the limbs also play key sensory roles in maintaining balance. The central nervous system coordinates all of the input to maintain balance for the patient. Disturbance in any of these sensory areas may result in the subjective sensation of dizziness or unsteadiness. True vertigo most commonly results from disturbances in the inner ear balance organs, but may result from central nervous system problems as well. General disturbances in the metabolism of the body may lead to dizziness by interfering with coordination of impulses in the brain.

The brain, reacting to normal or abnormal impulses, may respond in such a way that the individual has a false feeling of movement resulting in staggering or falling. The brain’s influence on the body’s glands and muscles may result in the individual breaking out in a cold sweat, having nausea and vomiting, or feeling very faint.

Types of Dizziness

Sensations of unsteadiness, imbalance or disorientation in relationship to one’s surroundings may result from disturbances in the ear, neck muscles and joints, the eyes, the nervous system connections of these structures, or a combination of any of the above.

Ear Dizziness

Ear dizziness, one of the most common types of dizziness, results from disturbances in the blood circulation or fluid pressure in the inner ear chambers, from direct pressure on the balance nerve, or physiologic change involving the balance nerve. Inflammation or infection of the inner ear or balance nerve is also a major cause of ear dizziness.

The inner ear mechanism is about the size of a pea, and is extremely sensitive. There are two inner ear chambers: one for hearing (cochlea), and one for balance (vestibule and semicircular canals). These chambers contain a fluid which bathes the delicate nerve endings. These nerve endings are stimulated when there is movement of the fluid. Nerve impulses are then transmitted to the brain by the hearing and balance nerves. The nerves pass through a small bony canal (internal auditory canal) accompanied by the facial nerve.

Any disturbance in pressure, consistency, or circulation of the inner ear fluids may result in acute, chronic, or recurrent dizziness, with or without hearing loss and head noise. Likewise, any disturbance in the blood circulation in this area or infection of the region may result in similar symptoms. Dizziness may also be produced by over stimulation of the inner ear fluids, such as one encounters when he spins very fast and then suddenly stops.

Central Dizziness

Central dizziness is usually unsteadiness brought about by failure of the brain to correctly coordinate or interpret the nerve impulses which it receives. An example of this is the "swimming feeling" or unsteadiness that may accompany emotion stress, tension states, and excessive alcohol intake. Circulatory inefficiency, tumors, or injuries may produce this type of unsteadiness, which or without hearing impairment. A feeling of pressure or fullness in the head is common. Occasionally true vertigo (spinning) may be caused by central problems.

Neck Dizziness

Neck dizziness (cervical vertigo) results from abnormal or uncoordinated nerve impulses being sent to the brain from the neck muscles.

The neck muscles are constantly sending nerve impulses to the balance centers of the brain to help maintain equilibrium. Spasm (tenseness) of the muscles may result in an abnormal nerve discharge, leading to unsteadiness or dizziness. This spasm may result from injury, arthritis of the spine or from pressure on nerves in the neck.

Muscle-Joint Dizziness

Muscle-joint dizziness is relatively uncommon. Any disturbance of sensation arising from the muscles and joints in the limbs (such as occurs in the muscular dystrophies and other abnormalities) produces this type of unsteadiness. Such as example is the unsteadiness experienced when one tries to walk on a leg that has "gone to sleep".

Visual Dizziness

Eye muscle imbalance or errors of refraction may produce unsteadiness. An example of this is the unsteadiness which may result when on attempts to walk while wearing glasses belonging to another individual.

Another example of visual dizziness is that occasionally produced if one is seated in a car looking out the side window at passing objects. The eyes respond by sending a rapid series of impulses to the brain indicating that the body is rotating. On the other hand, the ears and the muscle-joint systems send impulses to the brain indicating that the body is not rotating, only moving forward. The brain, receiving these confused impulses (from the eyes indicating rotation, from the ears and muscle-joint systems indicating forward motion) sends out equally confusing orders to various muscles and glands that may result in sweating, nausea and vomiting. When one sits in the front seat looking forward, the eyes, ears, and muscle joint systems work more uniformly and one is less likely to develop car sickness.

A visual disturbance may be caused by dizziness from other sources. Intermittent inability to focus the eyes, difficulty reading or intermittent blurring of vision, although at time the result of anxiety or tension, may result from small reflex movements of the eyes call nystagmus. The nystagmus is common during severe dizziness.

Warning

Persons subject to dizziness should exercise caution when swimming. Buoyancy of the water results in an essentially weightless condition, and visual orientation is greatly impaired if one’s head is under water. Therefore, orientation depends almost entirely on the inner ear balance canals. An attack of dizziness at this time could be very dangerous. Similarly, individuals who have lost both inner ear balance canals should avoid underwater swimming.

Ear Dizziness: Symptoms

Any disturbance affecting the function of the inner ear or its central connections may result in dizziness, hearing loss, or tinnitus (head noise). These symptoms may occur singly or in combination, depending upon which functions of the inner ear are disturbed.

Ear dizziness may appear as a whirling or spinning sensation, unsteadiness, or giddiness and lightheadedness. It may be constant, but is more often intermittent, and is frequently aggravated by head motion or a sudden change in position. Nausea and vomiting may occur, but one does not lose consciousness as a result of inner ear dizziness.

Diagnosing the cause of dizziness

Dizziness may be caused by any disturbance in the inner ear, the balance nerve, or its central connections. This can be due to a disturbance in circulation, fluid pressure or metabolism, infections, neuritis, drugs, injury or growths.

At times, an extensive evaluation is required to determine the cause of dizziness. The tests necessary are determined at the time of examination and may include detailed hearing and balance tests, x-rays, and blood tests. A general physical examination and neurological tests may be advised.

The object of this evaluation is to be certain that there is no serious or life-threatening disease, and to pinpoint the location of the problem. This lays the groundwork for effective medical or surgical treatment.

Imbalance related to aging

Some individuals develop imbalance as a result of the aging process. In many cases this is due to circulatory changes in the very small blood vessels supply the inner ear and balance nerve mechanism. Fortunately, these disturbances, although they may persist, rarely become worse.

Postural or positional vertigo is the most common balance disturbance of aging. This may develop in younger individuals as a result of head injuries or circulatory disturbances. Dizziness on change of head position is a distressing symptom which is often helped by vesitbular exercises.

Temporary unsteadiness upon arising from bed in the morning is common in older individuals. At times, this feeling of imbalance may persist for an hour or two. Arising from bed slowly usually minimized the disturbance. Again, vestibular exercises may be useful to these individuals.

Unsteadiness when walking, particularly on stepping up or down, or walking on uneven surfaces, develops in some individuals as the progress in age. Using a cane and learning to use the eyes to help the balance is often helpful.

Neuritis

Neuritis is a physiological change, which occurs in the nerve after injury by trauma, a virus, autoimmune disease, or vascular compression. When this occurs, the balance function is impaired, resulting in a severe, and at times, prolonged episode of dizziness, often followed by some unsteadiness or movement sensation for weeks to years. Fortunately, this balance disturbance usually subsides in time and usually does not recur in the majority of cases. It may be, however, very chronic at a moderate to mild level.

Medical treatment is helpful in eliminating symptoms until the central nervous system can compensate for the injured nerve. This usually consists of dizziness suppressing drugs. On occasion, the central nervous system cannot compensate and surgery may be necessary.

METABOLIC DISTURBANCES

Occasionally metallic disturbances produce dizziness with r without associated hearing loss by interfering with the function of the inner ear or the central nervous system. Occasionally hearing loss may occur without the presence of dizziness. A change of thyroid function or abnormalities in the blood sugar is the most common metabolic disturbances resulting in dizziness. Rarely, fat metabolism abnormalities may also cause problems resulting in hearing loss and/or dizziness. Thyroid dysfunction is diagnosed by blood tests and treatment consists of taking a thyroid hormone. Abnormalities in the blood sugar are diagnosed, again by blood studies, and treatment usually consists of diet control and/or drug therapy. Fat metabolism problems are diagnosed by studies of the fatty acids and cholesterol in the blood. Treatment of these may consist of diet control with or without drug therapy.

ALLERGIES

Rarely, allergies may cause dizziness and/or vertigo. Allergies are usually diagnosed by obtaining a careful history and occasionally performing a series of skin tests with inhalants and food, and/or blood tests. Treatment usually consists of elimination of the offending agents when possible, or if this is not possible, by allergy shots to stimulate immunity.

INJURY

Injury to the head occasionally results in dizziness of longstanding origin. If the trauma is severe, it is usually due to the combined damage to the inner ear, balance nerve, and central nervous system. Lesser injury may damage any one, or a combination of these components. The unsteadiness is at times prolonged, and may or may not be associated with hearing loss and head noise as well as other symptoms.

Treatment consist of anti-dizziness medications, sedatives and occasionally medications to improve blood circulation. Symptoms will usually clear in a few months, but occasionally surgery is required to stop the symptoms, and in a few instances, not treatment will entirely eliminate the dizziness.

Tumors

A noncancerous tumor occasionally develops on the balance nerve between the ear and the brain. When this occurs, unsteadiness, hearing loss and head noise may develop. Extensive hearing tests, balance tests, and x-rays are necessary to diagnose such tumors.

If the diagnosis of a tumor is established, surgical removal is imperative. Continued growth of the tumor would lead to complications by producing pressure on vital adjacent nerves and the brain. An operation has been developed with allows the removal of these tumors at an early stage. Best results can be obtained if the tumor is diagnosed early and removed while the only symptom are hearing loss, dizziness, and tinnitus (head noise).

Meniere’s Disease

Meniere’s disease is a common cause of repeated attacks of dizziness, and is thought to be due (in most cases) to increased pressure of the inner ear fluids due to impaired metabolism of the inner ear. Fluids in the inner ear chamber are constantly being produced and absorbed by the circulatory system. Any disturbance of this delicate relationship results in overproduction or underabsorption of the fluid. This leads to an increase in the fluid pressure (hydrops) that may, in turn, produce dizziness, which may or may not be associated with fluctuating hearing loss and tinnitus. Meniere’s disease affects one ear about 60-70% of the time, but can affect both ears in 30-40% of patients.

A thorough evaluation is necessary to determine the cause of Meniere’s disease, if possible. A definite cause may not be found about 40% of the time. Circularity, metabolic, toxic, and allergic factors may play a part in any individual. Emotional stress, while making the disease worse, does not cause it.

Symptoms

Meniere’s disease is usually characterized by classic attacks consisting of vertigo (spinning) that varies in duration from a few minutes to several hours. Hearing loss and head noise, usually accompanying the attacks, may occur suddenly. Violent spinning, whirling, and falling associated with nausea and vomiting are common symptoms. Sensations of pressure and fullness in the ear or head are usually present during the attacks. The individual may be very tired for several hors after the overt spinning stops.

Attacks of dizziness may recur at irregular intervals and the individual may be free of symptoms for years at a time, only to have them recur. In between major attacks, the individual may have minor attacks occurring more frequently and consisting of unsteadiness lasting for a few seconds to minutes.

Occasionally hearing impairment, head noise, and ear pressure occur without dizziness. This type of Meniere’s disease is called cochlear dydrops. Similarly episodic dizziness and ear pressure may occur without hearing loss or tinnitus, and this is called vestibular hydrops.

Treatment of cochlear and vestibular hydrops is the same as for classic Meniere’s disease. The treatment of Meniere’s disease may be medical or surgical, depending upon the patient’s stage of the disease, life circumstances, and the condition of the ears. The purpose of the treatment is to improve the metabolism of the inner ear, to prevent the hearing loss and stop the vertigo (spinning).

Dizziness: Medical Treatment

The treatment of each individual patient varies according to the cause, magnitude, and frequency of symptoms. In addition, it depends upon the status of the hearing in the ear and lifestyle of the individual.

Medical treatment is aimed at improving the metabolic status of the inner ear. Several types of drugs are used depending upon the disease and the status of the patient. Most often the patient will have to take several drugs in combination, one of which is usually an anti-dizziness medication (labyrinthine suppressant). Sometimes drugs which dilute blood vessels are used, as well as drugs (diuretics) which decrease the amount of fluid in the inner ear. Changes in diet, thyroid medication, medication to control sugar metabolism, or other measures may be needed. Vasconstricting substances should be avoided to allow the inner ear to have maximum circulation. Such substances are caffeine (coffee) and nicotine (cigarettes). Very rarely allergic treatments may be necessary to control dizziness.

Dizziness: Surgical Treatment

Surgery is indicated when medical treatment fails to control the vertigo, or in special cases when it is used to prevent further hearing loss. The type of operation selected depends on the degree of hearing impairment in the affected ear, the life circumstances of the individual, and the status of the individual’s disease. In some operations, the hearing may be occasionally improved following surgery, and in others, it may become worse. In most cases it remains the same. Head noise may or may not be relieved, and in some cases may become even more marked. In most cases it is not relieved.

Surgery is most successful in relieving acute attacks of dizziness in the majority of patients. Some unsteadiness may persist over a period of several months until the opposite ear and the central nervous system are able to compensate and stabilize the balance system. In the event that a conservative operation does not relieve the attacks of dizziness, a second operation may be necessary.

 

   
Copyright © 2006 Texas Neurosciences Institute
Notice of Privacy Practices | Site Map