A balance disorder is a complex condition that causes unsteadiness and dizziness, and sensations of spinning, moving or floating. Part of the inner ear known as the labyrinth interacts with other body systems, including those of the eyes, bones and joints, to maintain balance. Normal balance requires the work of three sensory systems: the visual; the vestibular, which is located in the inner ear; and the somatosensory, which involves the muscular and skeletal systems. These systems, as well as the brain and nervous systems, can be the source of balance problems. When these systems do not function properly, vertigo, spinning, disorientation, trouble focusing the eyes, and poor balance may result.
Symptoms of Balance Disorders
Symptoms of balance disorders may come and go, or be constant. They may cause anxiety or panic when they occur, and may include:
- Motion sickness
- Blurry vision
Vomiting, diarrhea, and increased heart rate or blood pressure may also accompany these symptoms.
Causes of Balance Disorders
The symptoms of many balance disorders start suddenly, with no obvious cause. However, a balance disorder is often the result of another underlying medical condition. These medical conditions usually affect the visual, vestibular or general sensory systems, or the brain. Balance disorders may also be caused by:
- Certain medications
- Ear infections
- Head injury
- Blood-circulation disorders affecting the inner ear or brain
Low blood pressure can sometimes cause dizziness when an individual stands up too quickly.
Diagnosis of Balance Disorders
Because dizziness and vertigo are symptoms of many conditions, it can be hard to pinpoint the exact cause of balance disorders. Depending on a patient's symptoms, a series of audiologic, vestibular and movement tests may be performed in order to reach a diagnosis. Those tests may include:
- Hearing test
- Blood test
- MRI scan
- Posturography (posture and balance test)
An electronystagmogram, a test which measures eye movement and muscle control, may also be performed.
Advanced Diagnostic Testing
Videonystagmography, or VNG, is a diagnostic test used to determine if inner ear functions are the cause of dizziness and balance disorders. Interestingly, VNG is a series of tests that examine the involuntary movement of the eyes known as nystagmus, to monitor and diagnose problems with the ears. The movements are recorded through infrared cameras in the form of goggles placed over the eyes. The only discomfort from this comprehensive exam comes as a result of wearing goggles. VNG is one of the only tests that can determine if the problem is unilateral, related to one ear, or bilateral, related to both ears.
The VNG exam measure the movement of the eyes in a variety of situations and include the following varieties of tests:
The gaze test records eye movements as the patient looks straight ahead, to the left, to the right, up and down with eyes open and closed. This test looks for the presence of nystagmus, or involuntary motion.
The saccades test records eye movement as the patient looks back and forth between two horizontal points, as in reading. This test looks for defects of saccadic eye movement.
Pendular Tracking Testing
Pendular tracking testing records eye movement as the patient follows a moving visual target. This test looks for abnormalities of pursuit eye movement.
With the optokinetic test, eye movements are recorded as the patient looks at vertical stripes moving at different speeds. This test determines the presence of nystagmus, which becomes stronger as stimulus speed increases.
During the positional test, the patient's head and body are moved into various positions and the eyes are then recorded while both open and closed to detect the presence of any nystagmus.
With the hallpike maneuver, the patient's head is moved rapidly and the presence of any nystagmus is checked after each movement.
During the caloric test, each ear is irrigated with air or water above body temperature and then below body temperature. This test provokes nystagmus and then examines the responses of each ear to determine if one vestibular mechanism is more sensitive than the other.
While this test is comprehensive, it is completely non-invasive with no side effects. Patients can drive themselves home immediately following the exam. A doctor will determine whether a VNG test is appropriate for diagnosing each patient's condition.
Types of Balance Disorders
Identifying the underlying cause and the type of balance disorder are both important for successful treatment. Balance disorders are commonly characterized by their symptoms or causes. There are several types of common balance disorders.
Benign Paroxysmal Positional Vertigo
Also known as BPPV, benign paroxysmal positional vertigo is a condition that causes feelings of vertigo after specific position changes of the head. BPPV may be caused by an infection or inflammation of the ear that causes the calcium particles to shift, resulting in balance problems and vertigo. Patients who suffer from BPPV may have brief periods of vertigo that come and go.
Labyrinthitis results in dizziness and a loss of balance. It is usually caused by an infection or inflammation of the inner ear that is the result of an upper-respiratory infection. Labyrinthitis is frequently a result of chronic, untreated middle-ear infections. Symptoms of labyrinthitis usually subside when the infection clears up.
Meniere's disease symptoms, which are caused by an imbalance of fluid in the inner ear, include vertigo, hearing loss and ringing in the ears. Symptoms of Meniere's disease may vary in both frequency and intensity. Some patients experience many symptoms within a short period of time, followed by months or years without them.
Also known as vestibular neuritis, vestibular neuronitis is the swelling of the vestibular nerve, which is responsible for sending balance signals from the inner ear to the brain. This condition usually causes vertigo. Vestibular neuronitis often follows a cold or other viral infection, although by the time symptoms arise, the viral infection is usually long gone.
Perilymph fistula is the leakage, caused by a physical injury or exertion, of inner-ear fluid. The symptoms of perilymph fistula may include dizziness, vertigo, nausea and vomiting. Some patients experience ringing or fullness in the ears, and many notice hearing loss. Symptoms may get worse when there is a change in altitude or air pressure.
When a cause for the balance disorder is determined, a specific treatment plan can be created.
Treatment for Balance Disorders
Treatment for a balance disorder depends on its cause, and treating the cause often eliminates the balance problem. The following treatments may also help to relieve symptoms:
- Balance-training exercises
- Lifestyle changes, such as limiting alcohol and caffeine
- Antibiotics for ear infections
- Anti-vertigo and anti-nausea medications
A vestibular rehabilitation therapist can also assist patients by developing individualized treatment plans that combine head, body and eye exercises designed to decrease dizziness and nausea. Surgery on the vestibular organs may be recommended for patients whose symptoms cannot be controlled by more conservative methods.