Biology 202
1999 First Web Reports
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In order to better understand vertigo, it is first necessary to look into where equilibrium and movement are maintained within the body. Equilibrium in our bodies is coordinated primarily by the brain, specifically at the brainstem, located in the neck area. The environment provides the information necessary for the equilibrium center to determine which position to place the body in. There are three main places in which information is received: the eyes provide visual information, the ears provide vestibular and auditory information, and the articulations provide proprioceptive information. In general, the eyes help position the body according to different horizontal angles in relation to the ground. The ears allow the body to acknowledge any type of movement, such as acceleration or deceleration, by registering various sounds (1). Movement is also processed in parts of the brain, as well as in the ears. The frontal lobes of the brain initiate and coordinate the planning of movements. The basal ganglia, in the ears, add control and fluidity to movements, and the cerebellum processes information from and to the rest of the body.

Vertigo is a classification under dizziness that results in a spinning sensation or illusion of movement. (Many people who experience dizzy sensations often do not have vertigo, but instead, are found to have the common lightheadedness). Vertigo arises from disturbances in the vestibular system or neural structures such as the cerebellum, the brain stem, and the proprioceptive fibers along the spine.

Symptoms of vertigo include "an unsteadiness sensation when walking, rotary sensations, a sensation of being afloat on the air, feeling of a hollow space in the head, etc" (2). Some autonomic symptoms such as sweating, nausea, and vomitting are found to accompany vertigo attacks (3). Also, another symptom found is nystagmus. This is when the eyes move about involuntarily. These symptoms and sensations can occur at different random times and last temporarily, or they can be persistent and last permanently. The vertigo problem can be dervived from the ear or the brain. If it comes from the ear, it is termed peripheral. Peripheral causes of vertigo include Meniere's Disease, ear trauma, labyrinthitis, and Vestibular Neuronitis (1). On the other hand, if the problem comes from the brain, then it is called central. Central causes of vertigo include stroke/or tumor in the brainstem, multiple sclerosis, migraine, drugs (sedatives), panic or anxiety, and head trauma. Peripheral dizziness can be seen to be less severe of the two because it does not severely affect the brain.

There are three main types of vertigo: spontaneous vertigo, recurrent attacks of vertigo, and positional vertigo. In order to distinguish what type of vertigo an individual might have, certain tests are conducted. These tests include a head CT, a MRI scan of the head, caloric stimulation (testing eye reflexes), and an EEG (auditory potential stidues). Normally, treatment is not necessary, especially for symptoms that last for a short time. Out of the three, the most common type of vertigo is the positional vertigo (4). This is the disorder where with particular head positions, an abnormal sense of movement is felt. Some head positions include lying on one side or turning your head back. In these positions, one might get the sensation that the room around you is moving, or that you are moving. Positional vertigo is initiated by the position of the head, while in other types of vertigo, initiation is through movement of the head . vertigo (4)

The "postsuperior part of the temporal lobe" of the brain is the consciousness area of the brain. It is in this area that the thinking processes and higher learning functions like reading, speaking, writing are hindered due to the attention disorders that are found with vertigo. It is interesting to note that vertigo, as well as other types of dizziness, gives one the feeling of "imminent death". Although vertigo has not been found to lead to death, it continues to be an impediment for those trying to carry out normal daily activities (2) .

Within the body, there are four types of neurotransmitters of the vestibular system that help to control the effects of vertigo. The first is histamine. Histamine generally counteracts motion sickness. The second, norepinephrine, controls the intensity of reactions to vestibular stimulation. Third, dopamine affects vestibular compensations, and lastly, seratonin works in bringing down nausea (5) .

Many different types of treatment are being used to help treat those with vertigo. Often, vestibular suppressants and antiemetic drugs are given to patients. Vestibular suppressants are drugs that reduce nystagmus, which is caused by an imbalance in the body. Antiemetics are used to control nausea. Other drugs used are anticholinergics, antihistimines, and sedative hypnotics. Anticholinergics help to increase motion tolerance. Chemicals with anticholinergic effects are vital to treating vertigo (3) .

Another option for individuals with vertigo is to have surgical treatment performed. Surgical treatment of vertigo is done very few times a year, and is generally not prescribed for patients. There are two categories of surgical treatment. The first is corrective surgical treatment. In many cases, "the process of diagnosis is controversial, or the treatment itself is controversial" (6) . Therefore, the second treatment is more frequently administered. The second process is termed destructive surgical treatment. The word destructive is used to point out that these types of procedures are done to eliminate vertigo. However, in the process, hearing may be lost. When medical treatment or vestibular rehabilitation is not adequate to control the vertigo, patients often take this option. This treatment is done frequently with patients who have Meniere's disease, those with a disorder in the middle ear who suffer with vertigo or dizziness symptoms (7).

Current research is providing new insights to more useful and effective medical treatments for vertigo patients. There is hope that new antiemetics, those that are 5-HT3 antagonists (such as ondansetron, Zofran, and Kytril), will be more reliable in treating the nausea that comes with vertigo. Antiemetics have not yet been found to be effective in suppressing motion sickness (8) . The major concern with these new medications is that they are extremely high in cost and are therefore not prescribed on a normal basis.

Several other new agents are also being tested for treatment of vertigo. Although all the effects of these new drugs have not yet been confirmed, there is growing hope and promise for many vertiginous individuals. On the top of the list are calcium channel blockers, ie. flunarizine, cinnarizine, and verapamil. They are currently being used outside the US. Verapamil has "strong constipating effects", but this effect may aid in controlling diarrhea that results from vestibular inbalance. Calcium channel blockers are advantageous in that they carry anticholinergic and antihistiminic activity. There is ongoing research in trying to discover the importance of calcium channel blocking. So far, these agents have been used primarily on individuals with Meniere's disease, in hopes of alleviating migraine attacks. Many of the individuals tested have found these new drugs effective. The U.S., however, has not yet approved of these new chemicals (8).

Another agent being studied is the sodium channel blocker, specifically phehytoin (Dilantin). This drug is found useful against motion sickness, although further studies are still required. Another sodium channel blocker is Neurotin. This has been used to suppress nystagmus. Other promising agents include anticonvulsants and steroids, which reduce the duration of the vertiginous episodes (8) .

Although vertigo is not a fatal disorder, it continues to plague many individuals by giving them symptoms of dizziness along with other unsteady sensations of movement. Ongoing studies are starting to open new paths of treatment, especially with drugs such as antiemetics, calcium channel blockers, and sodium channel blockers. Even though many of these new treatments have yet to be approved, there is definitely an optimistic outlook for these individuals.

WWW Sources

2) Equilibrium Pathologies,

3)Vertigo (Seminar)...,

4) Benign Positional Vertigo,

5)Health Beat,

6) Surgical Treatment of Vertigo ,

7) Dizziness ,

8) Drug Treatment of Vertigo ,

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