Dizziness, a blanket term used to describe any feeling of unsteadiness, is one of the leading health complaints in the United States, affecting an estimated nine million people annually. For those over the age of 70 it’s the top reason for a visit to the doctor’s office.
Dizziness is the result of your brain receiving false signals from the balance system (comprised of the inner ear, eyes and sensory nerves). It senses movement and overcompensates, leading to a spinning sensation, weakness and faintness. There are many possible causes of dizziness including low blood pressure, anemia, dehydration, heat-related disorders, endocrine system disorders (e.g., diabetes, thyroid disease), heart conditions, high blood pressure, viral and bacterial infections, head trauma, hyperventilation, neurological disorders and certain medications.
Several balance disorders are commonly associated with dizziness and/or vertigo. Benign Paroxysmal Positional Vertigo (BPPV) involves brief but intense periods of vertigo that are triggered by specific changes in head position. It occurs when tiny crystals in the otolith organs become dislodged and migrate to the semicircular canals. Meniere’s disease is a chronic condition that causes vertigo, tinnitus, fullness in the ear and fluctuating hearing loss that may eventually become permanent. Meniere’s is usually confined to one ear and though its cause is unknown it may be the result of abnormal fluid buildup in the inner ear. Labyrinthitis is an inflammation of the inner ear usually caused by an infection. Its symptoms include vertigo, temporary hearing loss and tinnitus.
Patients who experience dizziness report a variety of symptoms depending on the exact nature of their balance disorder. These include:
- Vertigo (the sensation of movement in your surroundings)
- Blurred vision
Treatment for dizziness takes many forms, depending on the cause. Your doctor will try to target the underlying condition in order to reduce or eliminate the symptoms. Options include medications (antihistamines, sedatives, antibiotics, steroids), physical or occupational therapy, surgery, repositioning exercises, vestibular retraining programs and lifestyle modifications such as dietary changes and elimination of alcohol and nicotine).
Benign paroxysmal positional vertigo, commonly referred to as BPPV, is a vestibular disorder that causes vertigo. It occurs when calcium deposits in the inner ear become dislodged from the otolithic membrane and settle in the semicircular canals. Any change in the position of the head causes these tiny crystals to shift, triggering dizziness.
It isn’t always known what causes these calcium deposits to break loose, though this is commonly the result of a head injury, inner ear infection, damage from ear surgery or prolonged back position associated with bed rest. Migraines might also play a role. Older patients are susceptible to degeneration of the otolithic membrane related to normal aging.
BPPV is the most common cause of vertigo. The episodes of vertigo may be severe, but usually lasts for less than a minute. Other symptoms include dizziness or lightheadedness, loss of balance, blurred vision, nausea, vomiting and concentration difficulties.
If you are experiencing dizziness and unexplained episodes of vertigo, your doctor will administer tests to determine what is causing your symptoms. A diagnostic physical exam evaluates eye movements in response to specific head movements. Additional testing such as electronystagmography (ENG) and videonystagmography (VNG) may be used to detect abnormal eye movement; an ENG utilizes electrodes, while the VNG test relies on small cameras.
Fortunately, BPPV is one of the more easily treatable disorders. The standard approach involves a pattern of head movements used to move the calcium particle from the semicircular canal back to the utricle. Called the Canalith Repositioning Procedure (CRP) or the Epley maneuver, this brief procedure takes about five minutes and relieves symptoms in over 85 percent of patients.
If CRP is ineffective, patients may undergo surgery; both posterior semicircular canal occlusion and vestibular nerve section have proven effective, but carry a risk of hearing loss following surgery. Treatment with the antibiotic gentamicin and vestibular rehabilitation may also prove successful.
Videonystagmography, or VNG testing, is an exam of the balance system. It is used to determine the cause of a patient’s dizziness. Specifically, it measures whether a balance disorder can be attributed to a vestibular deficit (inner ear disease).
How VNG Testing Works
VNG testing uses a combination of video goggles and infrared cameras to measure involuntary eye movements, called nystagmus. Neural connections extend from the balance mechanism in the inner ear to the muscles of the eye. Rapid eye movements, which can only be captured using high-tech equipment, can indicate a disorder of the balance system. During a VNG test, you are given a series of visual tasks, and the camera records your eye movements.
There are generally four parts to VNG testing; in addition to evaluating rapid eye movements, a tracking test measures eye movements as they follow a visual target, a positional test measures dizziness in relation to different head positions and a caloric test evaluates responses to warm and cold water introduced through a tube in the ear canal. Testing is non-invasive and usually lasts between 60 and 90 minutes. There may be episodes of brief dizziness and some minor discomfort from the goggles, but otherwise you’re unlikely to experience side effects.
Preparing for the Test
Your doctor will likely advise you to avoid alcohol and certain medications for 48 hours prior to the test. These include sleeping pills, diuretics, tranquilizers, sedatives, antihistamines, muscle relaxers, anti-depressants and pain medications. Continue taking prescription medications unless instructed otherwise. You’ll need to avoid food or beverages for three hours before the test, except for water. Please also refrain from smoking during this time.
Call Tucson ENT Audiology at (520) 777-0495 for more information or to schedule an appointment.