Have you ever experienced vertigo? Vertigo is a subjective feeling like the room is spinning, and it causes dizziness and sometimes nausea in people who experience it. The most common cause of vertigo is benign proximal positional vertigo, often shorted to BPPV. Today, BPPV is considered a disturbance of the vestibular system, from where your brain receives information important to integrating your balance centre in the central nervous system.
Your brain has multiple sources of information to determine your balance: the eyes, the spine, proprioceptors in the body...but mostly, the vestibular system in the ear provides your brain with the information it needs to keep you upright and balanced.
This integration is so remarkable that we barely even know it exists until circumstances challenge it. For example, if you spin around on an office chair, or twirl on a merry-go-round, or dance in circles like a child, you will get the feeling of your vestibular system when you suddenly stop. The dizzy, world-spinning sensation is caused by the inner ear, which has three different tubular canals filled with fluid, called endolymph. The fluid, when spinning, stimulates a cranial nerve that sends information to your brain about the way in which the world is oriented. So, when it is properly functioning, this helps us maintain balance remarkably well. This highly effective system takes over when we trip or slip, and are quickly able to orient ourselves through balancing and righting reflexes.
But sometimes there are inconsistencies. For example, when we build up momentum by spinning on a chair and then we suddenly stop, the fluid in our ear continues to fire the nerve endings despite the fact that the rest of our body is still. Because the canals are still tricked into interpreting the spinning of the endolymph, our brain then interprets the world as if it were spinning. Since our eyes and our inner ear are intricately connected, there is a phenomenon that co-occurs called nystagmus. In nystagmus, our eyes continue to 'beat' to one side in a repetitive fashion, following the cue that our inner ear canals are providing.
If someone experiences BPPV, some of the same 'spinning' sensations occur as if the person has stepped off a merry-go-round. However, they may experience the dizzy sensation when only moving their head slightly to the right, left, or nodding (yes/no). Our current understanding of this is that small crystals, called otoliths, become stuck inside the canals. This sometimes happens after trauma, when we are hit in the head. Or a virus can also cause this. But often, it is thought that debris accumulates and becomes trapped in the canal in what we can canalithisis. The otolyth crystals float in the endolymph, and stimulate the nerve endings in the ampulla.
DIAGNOSIS:
When BPPV occurs, a chiropractor, physiotherapist or GP can usually diagnose the condition. A history of mechanically turning the head to one side, or perhaps laying upon one side, can sometimes help in the diagnosis. If a clinician can reproduce your subjective experience of vertigo by placing you onto your back into the Dix-Halpike maneuver, he or she can also then check for some objective findings, including the nystagmus, which often lags behind a few seconds after positioning your on your head/back.
TREATMENT:
Once diagnosed, and when more serious conditions are ruled out, treatment can begin. Treatment is aimed at either removing the crystal canaliths by positioning the head in such a way as the crystals and exit from the canal; or, alternatively, the movements allow the brain to habituate to the crystals, and the nervous system simply learns to adapt.
The Epley manoeuvre has evidence of effectiveness according to this Cochrane Review. In the Cochrane review, they link to this video below:
Similarly, recent publications have suggested the half somersault version of the repositioning. It seems to be as equally effective as the Epley Maneuver, and, in my experience it is easier to do in clinic, and for patients to do themselves at home. The principle is the same: you are either repositioning the canaliths so that they may exit from the canals, or, you are habituating the central nervous system so that it can return to its excellent functioning in every day life.
SOURCES
Hilton MP, Pinder DK. The Epley (canalith repositioning) manoeuvre for benign paroxysmal positional vertigo. Cochrane Database of Systematic Reviews 2014, Issue 12. Art. No.: CD003162. DOI: 10.1002/14651858.CD003162.pub3. Accessed 06 June 2022.
Khaftari MD, Ahadi M, Maarefvand M, Jalaei B. The Efficacy of the Half Somersault Maneuver in Comparison to the Epley Maneuver in Patients with Benign Paroxysmal Positional Vertigo. J Int Adv Otol. 2021;17(5):417-421. doi:10.5152/iao.2021.9072
Parnes, Lorne & Agrawal, Sumit & Atlas, Jason. (2003). Diagnosis and management of benign paroxysmal positional vertigo (BPPV). CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne. 169. 681-93.
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