Benign paroxysmal positional vertigo (BPPV) is a disorder caused by problems in the inner ear. Its symptoms are repeated episodes of positional vertigo, that is, of a spinning sensation caused by changes in the position of the head.BPPV is the most common cause of vertigo symptoms.
Vertigo, a distinct process some people confuse with dizziness, accounts for about 6 million clinic visits in the U.S. every year, and 17–42% of these patients eventually are diagnosed with BPPV. Other causes of vertigo include:
- Motion sickness/Motion Intolerance: a disjunction between visual stimulation, vestibular stimulation, and/or proprioception
- Visual exposure to nearby moving objects (examples of optokinetic stimuli: passing cars, falling snow)
- Other diseases: (labyrinthitis, Ménière's disease, migraine. etc.)
- Vertigo: Spinning dizziness, which must have a rotational component.
- Short duration (paroxysmal): Lasts only seconds to minutes
- Positional in onset: Can only be induced by a change in position.
- Nausea is often associated
- Visual disturbance: It may be difficult to read or see during an attack due to the associated nystagmus.
- Pre-syncope (feeling faint) or syncope (fainting) is unusual.
- Emesis (vomiting) is uncommon but possible.
- Rotatory (torsional) nystagmus, where the top of the eye rotates towards the affected ear in a beating or twitching fashion, which has a latency and can be fatigued (if you repeatedly continue placing yourself in the position to cause vertigo the symptoms should lessen each time).
- Nystagmus should only last for 30 seconds to one minute.
The spinning sensation experienced from BPPV is usually triggered by movement of the head, will have a sudden onset, and can last anywhere between a few seconds to several minutes. The most common movements patients report triggering a spinning sensation are tilting their head upwards in order to look at something, and rolling over in bed.
Within the labyrinth of the inner ear lie collections of calcium crystals known as otoconia or otoliths. In patients with BPPV, the otoconia are dislodged from their usual position within the utricle and they migrate over time into one of the semicircular canals (the posterior canal is most commonly affected due to its anatomical position). When the head is reoriented relative to gravity, the gravity-dependent movement of the heavier otoconial debris (colloquially "ear rocks") within the affected semicircular canal causes abnormal (pathological) fluid endolymph displacement and a resultant sensation of vertigo. This more common condition is known as canalithiasis.
In rare cases, the crystals themselves can adhere to a semicircular canal cupula rendering it heavier than the surrounding endolymph. Upon reorientation of the head relative to gravity, the cupula is weighted down by the dense particles thereby inducing an immediate and maintained excitation of semicircular canal afferent nerves. This condition is termed cupulolithiasis.
There is evidence in the dental literature that malleting of an osteotome during closed sinus floor elevation, otherwise known as osteotome sinus elevation or lift, transmits enough percussive and vibratory forces capable of detaching otoliths from their normal location and leading to the symptoms of BPPV.
It can be triggered by any action which stimulates the posterior semi-circular canal which may be:
- Tilting the head
- Rolling over in bed
- Looking up or under
- Sudden head motion
- Post head injury
- Changes in barometric pressure - patients often feel symptoms approximately two days before rain or snow
- Lack of sleep (required amount of sleep may vary widely)
Although BPPV can occur at any age, it is most often seen in people over the age of 60.Besides aging, there are no major risk factors known for developing BPPV, although previous episodes of trauma to the head or inner ear infections known as labyrinthitis, may predispose individuals to future development of BPPV.
The condition is diagnosed by taking a patient history, and by performing the Dix-Hallpike maneuver and/or the roll test.Patients with BPPV will report a history of vertigo as a result of fast head movements. Many patients are also capable of describing the exact head movements that provokes their vertigo.
The Dix-Hallpike test is a common test performed by examiners to determine whether the posterior semicircular canal is involved. It involves a reorientation of the head to align the posterior semicircular canal (at its entrance to the ampulla) with the direction of gravity. This test will reproduce vertigo and nystagmus characteristic of posterior canal BPPV.
When performing the Dix-Hallpike test, patients are descended quickly to a supine position with the neck extended by the clinician performing the manoeuvre. For some patients, this maneuver may not be indicated and a modification may be needed that also targets the posterior semicircular canal. Such patients include those who are too anxious about eliciting the uncomfortable symptoms of vertigo and those who may not have the range of motion necessary to comfortably be in a supine position. Obesity can also present a challenge when performing this assessment. The modification involves the patient moving from a seated position to side-lying without their head extending off the examination table, such as with Dix-Hallpike. The head is rotated 45 degrees away from the side being tested and the eyes are examined for nystagmus. A positive test is indicated by patient report of a reproduction of vertigo and nystagmus. Both the Dix-Hallpike and the side-lying testing position have yielded similar results and as such the side-lying position can be used if the Dix-Hallpike cannot be performed easily.
The roll test can determine whether the horizontal semicircular canal is involved. The roll test requires the patient to be in a supine position with his/her head in 20° of cervical flexion. Then the examiner quickly rotates the head 90° to the left side, and checks for vertigo and nystagmus. This is followed by gently bringing the head back to the starting position. The examiner then quickly rotates the head 90° to the right side, and checks for vertigo and nystagmus.In this roll test, the patient may experience vertigo and nystagmus on both sides, but rotating towards the affected side will trigger a more intense vertigo. Similarly, when the head is rotated towards the affected side, the nystagmus will beat towards the ground and be more intense.
As mentioned above, both the Dix-Hallpike and roll test provoke the signs and symptoms in subjects suffering from archetypal BPPV. The signs and symptoms patients with BPPV experience are typically a short-lived vertigo, and observed nystagmus. In some patients, though rarely, the vertigo can persist for years. Assessment of BPPV is best done by a health professional skilled in management of dizziness disorders, commonly a physiotherapist, audiologist or other medical physician.
The nystagmus associated with BPPV has several important characteristics which differentiate it from other types of nystagmus.
- Positional: the nystagmus occurs only in certain positions
- Latency of onset: there is a 5-10 second delay prior to onset of nystagmus
- Nystagmus lasts for 5–120 seconds
- Visual fixation suppresses nystagmus due to BPPV
- Rotatory/Torsional component is present or (in the case of lateral canal involvement) the nystagmus beats in either a geotropic (towards the ground) or ageotropic (away from the ground) fashion
- Repeated stimulation, including via Dix-Hallpike maneuvers, cause the nystagmus to fatigue or disappear temporarily.
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