Disruption along any portion of the anatomical pathway described above can affect one’s perception of balance or equilibrium. A problem with the inner ear portion of the pathway or the sensory information being relayed to the brain via the vestibulocochlear nerve is termed a peripheral vestibular disorder. If the problem affecting one’s balance is due to damage of a structure within the brain itself, which then affects the reception and integration of balance information, it is termed a central vestibular disorder.
Peripheral or central vestibular disorders can both cause vertigo. Some cases of vertigo may be due to both peripheral and central vestibular disorders.
The most common peripheral vestibular disorders causing vertigo are benign paroxysmal positional vertigo, Meniere’s disease, and vestibular neuronitis/neuritis or labyrinthitis. Other causes that will be discussed in this guide are migraine associated vertigo, acoustic neuroma, and vertigo as a symptom of Multiple Sclerosis.
Benign Paroxysmal Positional Vertigo
Benign paroxysmal positional vertigo (BPPV) is a common clinical disorder of balance, which is characterized by recurrent vertigo spells that are brief in nature (usually 10-60 seconds) and are most often triggered by certain head positions. Benign, in medical terms, means it is not threatening to life. Paroxysmal means it comes with a rapid and sudden onset or increase in symptoms.
BPPV is the most common cause of recurrent vertigo. The cause of BPPV is proposed to be calcium carbonate crystals (called otoconia or otoliths), which are sometimes termed ‘ear rocks’ within the semicircular canals of the inner ear. Usually these crystals are located within the utricle and saccule of the ear. It is thought that these crystals dislodge and migrate to the semicircular canals of the ear. The cause of this dislodgement is postulated to be a number of possible reasons such as an ear or head injury, an ear infection or surgery, or from natural degeneration of the inner ear structures. Often a direct cause cannot be identified.
The otoconia settle in one spot in the canal when the head is still. The most common canal for settlement in is the posterior semicircular canal. A sudden change in head position, often brought on by activities such as rolling over in bed, getting out of bed, bending over, or looking upwards, causes the crystals to shift. This shift in turn sends false signals to the brain about equilibrium, and triggers the vertigo.
Vertigo due to BPPV can be severe and accompanied by nausea. The attacks can occur seemingly for no reason and then disappear for weeks or months before returning again. Generally BPPV affects only one ear and although it can occur at any age it is often seen in patients over the age of 60 and more often in women. Nystagmus is usually present.
Vestibular Neuronitis or Labyrinthitis
Vestibular neuronitis or labyrinthitis is an inflammation of the inner ear or its associated nerve (the vestibular portion of the vestibulocochlear nerve), which causes vertigo. Hearing may also be affected if the infection affects both portions of the vestibulocochlear nerve.
The vertigo caused by vestibular neuronitis or labyrinthitis is of a sudden onset and can be mild or extremely severe. Nausea, vomiting, unsteadiness, decreased concentration, nystagmus and impaired vision may also accompany the vertigo. Most often the infections that cause inflammation of the inner ear or the vestibulocochlear nerve are viral in nature as opposed to bacterial. Proper diagnosis of the cause is important in order to provide the most effective and appropriate treatment.
Meniere's Disease
Meniere's disease is a chronic incurable vestibular disorder characterized by symptoms of episodic severe vertigo, fluctuating hearing loss, ear ‘fullness’ and/or ringing in the ear (tinnitus), and nystagmus.
This disease derives its name from a French physician, Prosper Meniere, who theorized in the late 1800’s about the cause of this repertoire of symptoms, which he noted in many of his patients.
Early-stage acute attacks of Meniere’s disease vary in their length anywhere from 20 minutes to 24 hours. The attacks can occur regularly within a week or may be separated by weeks or months. Other symptoms may coincide with the attack such as anxiety, diarrhea, trembling, blurry vision, nausea and vomiting, cold sweats, and a rapid pulse or heart palpitations. Following the attacks patients often feel extreme tiredness, which requires many hours of rest to recover. For some patients time between attacks may be symptom free but other patients report ongoing related symptoms even between attacks.
The exact cause of Meniere’s disease is still not certain but it is theorized that it is due to an abnormal amount of endolymph fluid collecting in the inner ear and/or an abnormal buildup of potassium in the inner ear.
Migraine Associated Vertigo
Some patients who suffer from migraines (approximately 25-35%) experience migraine associated vertigo (MAV). MAV, (also called a vestibular migraine), may also be accompanied by nausea or vomiting and may last a few seconds or a few days. Other vestibular symptoms may also be noted in association such as motion intolerance, sensitivity to head movement, dizziness, a feeling of pressure in the ears, imbalance and spatial disorientation. With MAV the symptom of vertigo may precede the onset of the migraine or may appear as the headache pain develops. Vertigo may also occur during a headache-free time frame. Some patients will also present with a true BPPV after the migraine event has ceased.
Acoustic Neuroma
An acoustic neuroma is a benign (non-cancerous) tumour on the vestibulocochlear nerve. Early symptoms are related to loss of hearing in the affected ear, ringing in the ear (tinnitus), dizziness, and a feeling of fullness in the ear. The tumour is slow growing so symptoms come on gradually and may be easily overlooked in the early stages. As the tumour grows it may push on other nerves in the area and symptoms such as headaches or pain and numbness in the face may appear. Vertigo or other balance issues may arise with growth of the tumour.
Vertigo as a symptom of Multiple Sclerosis
Multiple Sclerosis (MS), which causes a demylenation of nerves, primarily attacks the cerebellum of the brain, as well as the brain stem (including the cranial nerves such as the vestibulocochlear nerve), and the spinal cord. The cerebellum is particularly important in regards to balance as it helps to integrate information received by the brain in order to both maintain balance and arrange coordinated movements. Damage to either the cerebellum and/or the vestibulocochlear nerve due to MS can cause vertigo.
Approximately 20% of MS sufferers will experience vertigo as a symptom. The vertigo attacks associated with MS can be short-lived or last for days or weeks at a time. A much more common symptom of MS sufferers rather than vertigo is general dizziness or lightheadedness.
Other causes of Vertigo
Although most cases of vertigo are related to peripheral or central vestibular disorders, other causes of vertigo may be identified such as alcohol intoxication, metabolic disorders, bacterial or viral infections, side-effects from medications, or side effects from overexposure to specific chemicals (ototoxicity). Even severe emotional issues causing anxiety can manifest in vertigo. In some rare cases, however, a cause for the symptom of vertigo goes unknown.
