Common Vestibular Disorders
Common disorders of the vestibular system include:
- benign paroxysmal positional vertigo (BPPV)
- vestibular neuritis
- Ménière’s disease (endolymphatic hydrops)
- vascular dizziness
- perilymphatic fistula
- bilateral vestibular loss
BPPV is the most common cause of vertigo. In BPPV, people usually describe brief (less than a minute) bouts of vertigo (spinning or tilting) with specific movements, such as rolling over in bed, looking up or down, or getting in or out of bed. BPPV is caused by tiny calcium-carbonate crystals (which belong in the otoliths) floating into the semi-circular canals. This changes the way fluid moves in the inner ear, causing vertigo with specific head movements. BPPV can be caused by trauma to the head or viral infections of the inner ear, but it most commonly occurs without any apparent cause, in particular in older age.
Treatment of BPPV is usually conducted in the physician or physiotherapist’s office and involves a repositioning manoeuvre that uses gravity to move the crystals back in to the otolith. Normally the symptoms subside immediately and the crystals reabsorb over the coming days. Repositioning may need to be done on multiple occasions and BPPV may return in the future. Very rarely, surgery may be considered if the repositioning manoeuvres are unsuccessful.
Read more about BPPV – summary of a presentation by Dr. Jane Lea.
Neuritis (inflammation of a nerve), usually due to a virus, may affect the vestibular nerve. When this happens the balance centres of the brain are over-stimulated, which results in severe dizziness and vertigo. Fortunately, vestibular neuritis usually subsides with time and it does not normally recur. Certain medications such as steroids and/or antivirals may help in the acute phase to decrease the severe symptoms or improve the long-term outcome. Many people heal naturally. However, some people have long-term weakness (or paresis) of this nerve. If this occurs, exercises (vestibular and balance rehabilitation) can speed–up recovery or treat symptoms such as dizziness, blurred vision and imbalance.
In Ménière’s disease, the endolymphatic sac fails to absorb fluid properly. This change in inner ear fluid pressure results in dizziness and hearing loss.
These changes are usually caused by excess inner ear sodium (salt). In addition to dizziness, which usually lasts hours, patients may have fluctuating hearing, tinnitus, and a feeling of fullness in the affected ear. It can occasionally affect both ears.
The cause of this disorder is not known and may vary from person to person. The spells can sometimes be induced by excess salt intake, stress, weather changes, or allergies.
Treatment usually includes restriction of salt (sodium) intake and the use of a diuretic (water pill). Sometimes, anti-dizziness medication like Antivert or Valium can decrease the severity of the acute spells, but they do not cure the disease or help with symptoms that are present between attacks.
Vestibular rehabilitation may help with dizziness, blurred vision and imbalance related to Ménière’s disease, but rehabilitation cannot prevent future attacks.
In severe cases of Ménière’s disease, surgery may be needed. Fortunately, there are many surgical options. Of all these options, only sac decompression surgery attempts to improve function of the inner ear. The remaining options attempt to selectively ablate (remove or destroy) the malfunctioning balance (vestibular) nerve, and sometimes the hearing nerve as well.
Proper function of the balance system also requires appropriate nerve connections within the brain. If these balance areas do not get enough blood, even temporarily, dizziness and imbalance can occur.
Causes of vascular dizziness are varied. Arthritis in the neck can cause compression of arteries to the head, or cholesterol plaques may narrow the arteries causing decreased blood flow. Often, blood pressure to the brain can drop temporarily when standing up quickly, especially in older people or people on blood pressure medication. Special tests such as MRI (magnetic resonance imaging), X-ray or ultrasound tests may be needed to accurately diagnose these problems. Other brain disorders that may affect the vestibular system include certain types or stroke, traumatic brain injury, concussion, brain tumours, or some types of migraine. Treatment depends on the cause, and may include medication, surgery, or vestibular rehabilitation.
The inner ear is a fluid-filled space within the temporal bone of the skull. If a fluid leaks from this space, dizziness and hearing loss may occur. The leak usually occurs in or near the natural structures of the inner ear, such as the oval and round membranous windows. The leak may occur naturally, with heavy straining, or after trauma. With rest, inner ear leaks may heal on their own. In some cases, minor surgery is required to plug the leak. Some people have on-going symptoms that require rehabilitation or to learn new strategies to avoid symptoms.
Some people are born with abnormalities such as children who are born with an abnormal connection between their brain and ear, a so-called “enlarged vestibular aqueduct.” This can sometimes be detected on a CT (computerized tomography) scan and may lead to fluctuating hearing loss as well as dizziness.
Rarely, people can suffer from loss of vestibular function on both sides simultaneously. This may occur due to autoimmune disease, after certain medications (such as Gentamicin), or without known cause. Unsteadiness and falls are a primary concern. Education is important to prevent falls and vestibular rehabilitation will address the visual blurring and imbalance.
Rarely, tumours can be a cause of dizziness. The most common vestibular tumours are not cancerous. Acoustic neuromas (or vestibular schwannomas) are benign tumours of the balance nerve. They can cause unsteadiness, hearing loss, and tinnitus. Surgery is the most effective treatment for an acoustic neuroma.