Vision plays a significant role in our ability to balance, orient ourselves in space, and process movement of things in our environment. Approximately twenty percent of the nerve fibers from the eye neural tracts (the neural fibers within the brain that connect to the eye) interact with the vestibular system, the parts of the inner ear and brain that help control balance and eye movements. The other key player in balance is the sensory information received through our joints and muscles.
If the vestibular system is damaged by disease, aging, head injury, or sometimes for no apparent reason, persons with a vestibular disorder often experience extreme difficulty with balance and movement, as well as with their perception of space. As a result, functioning at work or school, or performing routine daily tasks in environments with excessive visual stimulation, such as a grocery store or shopping mall, may be difficult.
What are the common symptoms associated with vestibular disorders?
- Vertigo and dizziness
- Imbalance and Spatial disorientation
- Vision disturbances
- Hearing changes
- Cognitive and/or psychological changes
Treatment for Dizziness
Balance problems related to vision is first aimed at correcting (if possible) the underlying cause of the disorder. A combination of special lens and prism correcting spectacles, neuro-optometric rehabilitative therapy and balance and/or vestibular therapy can be an effective treatment for reducing or resolving these symptoms.
What visual dysfunctions may contribute to dizziness and balance?
A visual condition where there is a significant difference in the perceived size of images, one eye to the other. This can cause disorientation, eyestrain, headache, and dizziness and balance disorders.
Normally the eyes work in perfect synchrony. In this instance, one eye will aim higher than the other. In an effort to adjust to the vertical misalignment of the eyes, the person will frequently tilt their head to help align the eyes. This in turn can cause disorders in the vestibular fluid of the inner ear and lead to dizziness and balance disorders. It also leads to neck stiffness, muscle spasms and loss of mobility.
Binocular Vision Dysfunction:
Refers to the inability of the eyes to work together as a team. The eyes need to aim together and focus accurately at a point in space, and be able to quickly change gaze between closer and further objects how the visual system works as a team. Both components of near viewing (pointing and focusing) are controlled by neural connections in higher brain centers. Brain injury to these neural centers can lead to eye teaming and focusing issues resulting in double vision and/or blurred vision – setting the stage for dizziness and balance problems.
Other conditions that may contribute to dizziness and balance.
Acoustic neuroma (also called a vestibular schwannoma) is a serious but nonmalignant tumor that develops on the sheath of inner ear’s vestibulo-cochlear nerve, which transmits both balance and sound information to brain. (This nerve is also referred to as the acoustic nerve, hence the name.) As an acoustic neuroma grows, it compresses the vestibulo-cochlear nerve, usually causing hearing loss, tinnitus, and dizziness or loss of balance.
Dizziness in the elderly can be a result of problems with the vestibular, central (brain-related), and vision systems, as well as from neuropathy, psychological causes, and unknown (idiopathic) causes. Vestibular disorders, however, are thought to be the most common cause of dizziness in older people, responsible for approximately 50% of the reported dizziness in the elderly.
When a virus attacks, the immune system defends the body. When the immune system malfunctions, its defense capabilities sometimes mistake the body’s own cells for invading viruses or germs and attack them, which is referred to as autoimmunity. The immune system can attack the whole body or just certain systems, including the ear. When the ear is itself attacked, this is known as autoimmune inner ear disease. The progression of damage and functional loss caused by AIED can be rapid.
BPPV is a common vestibular disorder that causes vertigo, dizziness, and other symptoms due to debris that has collected within a part of the inner ear. This debris, called otoconia, is made up of small crystals of calcium carbonate (sometimes referred to informally as “ear rocks”). With head movement, the displaced otoconia shift, sending false signals to the brain.
Reduction or loss of vestibular function bilaterally results in difficulty maintaining balance, especially when walking in the dark or on uneven surfaces, and in a decrease in the patient’s ability to see clearly during head movements. Bilateral vestibular hypofunction and loss can occur as secondary to a number of different problems.
CANVAS is an easy to remember acronym for cerebellar ataxia, neuropathy, and vestibular areflexia. There are only a very few patients reported who have the requisite combination of two rare clinical findings (cerebellar ataxia and vestibular areflexia), and the very common peripheral neuropathy. Patients with CANVAS combine cerebellar ataxia (i.e. coordination problems — the CA), peripheral nerve damage (neuropathy – N), and loss of vestibular function (vestibular areflexia — the VA). This combination causes major disturbances to balance as each of these systems alone contributes to balance. Of course, when all are out at the same time, balance is much worse than when only one or two happens to be malfunctioning.
Neck pain often accompanies dizziness, but it may be difficult to tell whether the dizziness and the neck pain are related or just coincidental. Because true spinning vertigo is rarely associated with this syndrome, cervicogenic dizziness is a more accurate name for this syndrome. However, cervicogenic dizziness tends to be a controversial diagnosis, because there are no tests to confirm that it is the cause of the dizziness.
A cholesteatoma is a skin growth that occurs abnormally in the middle ear behind the eardrum. It is usually caused by repeated infection, and often takes the form of a cyst or pouch that sheds layers of old skin that builds up inside the ear. Over time, the cholesteatoma can increase in size and destroy the surrounding delicate bones of the middle ear. Hearing loss, dizziness, and facial muscle paralysis can result.
Trauma to the brain can result in abnormal vestibular system functioning. This article examines the vestibular/concussion connection, including symptoms, coping strategies, and prevention. An infographic and links to other resources is also included.
Enlarged Vestibular Aqueduct Syndrome (EVAS)
An enlarged vestibular aqueduct is usually accompanied by an enlargement of the endolymphatic duct and sac, which help maintain the volume and ionic composition of endolymph necessary for transmitting hearing and nerve signals to the brain. When EVA causes hearing loss or balance symptoms, it is referred to as enlarged vestibular aqueduct syndrome (EVAS).
Many dizzy patients are told they have “general vestibulopathy.” Is that a bonafide diagnosis? In this article, Dr. Gerard Gianoli discusses the definition and use of this term, and the role it plays in a patient’s diagnostic journey.
Labyrinthitis and vestibular neuritis are disorders resulting from an infection that inflames the inner ear or the vestibulo-cochlear nerve (the eighth cranial nerve), which connects the inner ear to the brain. Neuritis (inflammation of the nerve) affects the vestibular branch of the vestibulo-cochlear nerve, resulting in dizziness or vertigo but no change in hearing. Labyrinthitis (inflammation of the labyrinth) occurs when an infection affects both branches of the nerve, resulting in hearing changes as well as dizziness or vertigo.
Mal de débarquement literally means “sickness of disembarkment.” This term originally referred to the illusion of movement felt as an aftereffect of travel by ship or boat. Some experts now include other types of travel, such as by train and airplane, and situations with new and different movement patterns, such as reclining on a waterbed.
Migraine, a disorder usually associated with headache, is extremely common and can cause several vestibular syndromes. Studies suggest that about 25 percent of migraineurs experience dizziness or migraine during attacks. Migraine-associated vertigo (MAV) or vestibular migraine can occur with or without pain.
Ménière’s disease is a vestibular disorder that produces a recurring set of symptoms as a result of abnormally large amounts of a fluid called endolymph collecting in the inner ear. The exact cause of Ménière’s disease is not known. The four classic symptoms are vertigo, tinnitus, a feeling of fullness or pressure in the ear, and fluctuating hearing.
Neurotoxic vestibulopathy is a poisoning of neurons in the brain that help control balance as a result of exposure to a neurotoxin (naturally occuring substance), such as lead, or a neurotoxicant (synthetic substance), such as the anti-malarial drug, mefloquine (a.k.a. Lariam).
Otosclerosis is the abnormal growth of bone of the inner ear. This bone prevents structures within the ear from working properly and causes different types of hearing loss, depending on which structure within the ear is affected. In addition to hearing loss, some people with otosclerosis experience dizziness and balance problems.
Ototoxicity (“ear poisoning”) is due to exposure to drugs or chemicals that damage the inner ear or the vestibulo-cochlear nerve, which sends balance and hearing information from the inner ear to the brain. Ototoxicity can result in temporary or permanent disturbances of hearing, balance, or both. Many chemicals have ototoxic potential
Until recently, most medical professionals assumed that problems with vestibular function primarily affect adults, with only a small number of children being affected. However, there is growing evidence of vestibular system dysfunction in children, with consequent problems with gaze stability (seeing clearly with head movement), balance ability and/or the development of balance abilities, and dizziness.
A perilymph fistula is a tear or defect in one of the small, thin membranes that separate the middle ear from the fluid-filled inner ear. When a fistula is present, changes in middle ear pressure will directly affect the inner ear, stimulating the balance and/or hearing structures and causing symptoms.
Persistent Postural Perceptual Dizziness (PPPD)
PPPD – formerly known as Chronic Subjective Dizziness (CSD) – symptoms include non-vertiginous dizziness and unsteadiness that is increased by a person’s own motion, exposure to environments with a complex or moving stimuli (e.g., stores, crowds), and performance of tasks that required precise visual focus (e.g., reading, using a computer). PPPV is NOT a psychiatric disorder, but rather a neuro-otologic condition with behavioral elements.
Secondary endolymphatic hydrops involves abnormalities in the quantity, composition, and pressure of an inner-ear fluid called endolymph, apparently in response to an event or underlying condition such as head trauma or ear surgery. It can occur with other inner ear disorders, allergies, or systemic disorders.
Superior semicircular canal dehiscence syndrome results from an opening (dehiscence) in the bone overlying the superior (uppermost) semicircular canal within the inner ear. With this dehiscence, the fluid in the membranous superior canal (which is located within the tubular cavity of the bony canal) can be displaced by sound and pressure stimuli, creating certain vestibular and/or auditory signs and symptoms.
The vertebral and basilar arteries carry blood to the inner ear labyrinth, the vestibulo-cochlear nerve, and the brainstem. When blood flow through these vessels is restricted for any reason, it is called vertebrobasilar insufficiency. This is a common cause of vertigo in the elderly. The vertigo occurs suddenly without warning, usually lasts for several minutes, and can also be accompanied by nausea, vomiting, headache, and impaired vision.