March 30, 2019
You’re “Dizzy” … Now What??
Dizziness is a symptom. It is not a diagnosis.
Spatial disorientation, vertigo and disequilibrium are common symptoms reported by adults during visits to their doctors. They are all symptoms that can result from a peripheral vestibular disorder (a dysfunction of the balance organs of the inner ear) or central vestibular disorder (a dysfunction of one or more parts of the central nervous system that help process balance and spatial information). Dizziness can occur from many other causes.
The inner ear’s vestibular organs and the associated nerves and brain centers form a complex system that serves many functions and can be affected by a number of outside systems. A thorough evaluation of the inner ear, the brain, the cardiovascular and nervous system may therefore require several different kinds of tests to determine the cause of symptoms.
Balance is achieved and maintained by a complex set of sensorimotor control systems that include sensory input from vision (sight), proprioception (touch), and the vestibular system (motion, equilibrium, spatial orientation). Injury, disease, certain drugs, or the aging process can affect one or more of these components.
The ability to compensate for a vestibular disorder is compounded when there is more than one health problem that exists. For example, a mild vestibular disorder like Benign Paroxysmal Positional Vertigo (BPPV) can be much more problematic when accompanied by a visual deficit, history of migraines or a cardiovascular impairment.
The best way to assist in the process is to understand when your symptoms occur – make a journal and keep track.
- What are your symptoms? (be specific, there may be more than one symptom at a time)
- When do symptoms occur? (sitting to standing, lying down, exercise, the grocery store, etc)
- How long do they last? (seconds, minutes, hours, days)
- What makes you feel better or worse? (lying down, closing eyes, drinking water, eating, etc.)
Many times diagnostic tests take time to obtain or the results are negative and may not explain the cause of the symptoms. This is when Vestibular Rehabilitation may be appropriate to help the brain learn how to compensate back to a functional level and reduce symptoms. It may be appropriate to start Vestibular Rehabilitation in conjunction with the process of getting more diagnostic exams to begin the process of connecting the eyes, inner ear and body. Note, sometimes people do not see progress with Vestibular Rehab because other issues need to be addressed. Consult with your doctor about these options.
Nystagmus: is a vision condition in which the eyes make repetitive, uncontrolled movements. These movements often result in reduced vision and depth perception and can affect balance and coordination. There are different types of nystagmus (vertical, horizontal, rotational) and can be used in diagnosing vestibular or neurological disorders.
Comprehensive Vestibular Testing
Videonystagmography (VNG) uses goggles with video cameras to monitor the eyes. Both the video cameras and the electrodes can measure eye movements to evaluate signs of vestibular dysfunction or neurological problems. Generally these tests are performed in a room that is dark or with low lighting.
Parts of the VNG test battery evaluate the movement of the eyes as they follow different visual targets. Other parts observe eye movements as the head is placed in different positions. Another component is called the caloric test, which uses changes in temperature within the ear canal to stimulate part of the vestibular system. Air or water may be used to modulate the ear canal temperature, which may be warmer or cooler than body temperature. This test should provoke jerking eye movements (nystagmus) for a short time.
Rotary Chair is another way of evaluating how well the eyes and inner ear work together. These tests also use video goggles or electrodes to monitor eye movements. Rotation tests provide information beyond the ENG/ VNG about how well the balance organs are functioning.
Computerized Dynamic Posturography (CDP) tests postural stability or the ability to maintain upright posture in different environmental conditions. Maintenance of postural stability depends on sensory information from: the body’s muscles/joints, eyes, and inner ears. This testing investigates relationships among these three sensory systems and records the balance and posture adjustments made when different challenges are presented.
Head Impulse Testing (HIT) uses very small and quick movements of the head to evaluate reflex function, as opposed to the slow or moderate speeds used in rotation testing.
Vestibular Evoked Myogenic Potential (VEMP) testing is used to evaluate whether certain vestibular organs and associated nerves are intact and functioning normally. Responses in this test are measured from different muscles in the neck and around the eyes. VEMP testing uses adhesive, skin surface electrodes (like ENG or some rotational tests) and earphones (like those used during a hearing test). Sound is played for a few seconds through the earphones, the vestibular organs are stimulated and activate muscle responses, and electrodes record the results.
Audiometry (audiogram) measures hearing function. Hearing evaluations are an important part of vestibular diagnostics, because the inner ear contains both hearing and balance organs. The hearing and the balance system share the same nerve to the brain. This is the 8th cranial nerve called the Vestibulocochlear Nerve. More than one hearing test may be required when a person has a vestibular disorder, especially when there is evidence of hearing loss, a sensation of fullness in the ears, or tinnitus (ringing or noise in the ears).
Another part of a standard hearing test is Tympanometry, which can help detect problems between the ear drum and the inner ear. Tympanometry uses a small earpiece that creates pressure and plays sound in the ear canal to gather information. The same equipment can also be used for acoustic-reflex testing, which measures the reflex of muscles in the middle ear in response to pressure and loud sound.
Symptoms can be linked to a wide array of problems and is particularly commonly linked to blood-flow irregularities from cardiovascular problems. It may be recommended you consult with your Primary Care Physician or see a Cardiovascular Specialist to ensure your symptoms are not from your cardiovascular system.
Electrocardiogram (ECG) records the electrical activity of the heart, shows abnormal rhythms (arrhythmias), and can sometimes detect heart muscle damage.
Doppler ultrasonography (DUS) can detect abnormal blood flow leading from the heart, in the neck and to the brain.
Helical computed tomography angiography (CTA) is a noninvasive type of imaging that uses computed tomography (CT) technology and a contrast dye to provide an accurate, three-dimensional picture of the arteries on a computer screen. In addition to blood flow, these technologies can show changes in the dimension of the carotid and vertebral arteries, blood in the wall of the artery and changes to structures surrounding the blood vessels.
A Magnetic Resonance Imaging (MRI) uses a strong magnetic field and radio waves to create pictures, on a computer, of tissues, organs and other structures inside your body. It can be used to detect brain tumors, traumatic brain injury, developmental anomalies, multiple sclerosis, stroke, dementia, infection, and the causes of headache. MRIs of structures in and around the inner ear can be helpful in the diagnosis of some vestibular disorders.
Computerized Tomography (CT) special X-ray tests that produce cross-sectional images of the body using X-rays and a computer. A CT scan is an X-ray technique that is best for studying bony structures. The inner ear is inside of the skull’s temporal bone on each side. These scans are often used to look for abnormalities around the inner ear, such as fractures or areas with thinning bone.
Depending on your circumstances, other tests may be necessary to discover the cause of a balance disorder. Blood work, allergy tests, vision tests, and other exams may help rule out causes of imbalance that are unrelated to the vestibular system.
For more information on vestibular disorders please visit www.vestibular.org