BPPV is an enticingly mechanistic world and yet very difficult to understand. I think that this is due to our (my) limited understanding of the 3-dimensional topology of the semicircular canals; unfortunately there is no 3d-model available that you could turn and twist around until you get it. Also the pathology is not really clear: how big and how many otoliths? do they stick together? are they adherent to the wall? do they become entangled in the cupula’s sticky gelatinous mass? can they be freed?
Even in the simple case where straightforward test maneuvers show straightforward pathology, the otoliths can become dislodged into the horizontal or even anterior canal, leading to changing nystagmus on every other test – attendings never obtain the same results as their residents.
Then there is also the difficulty in differentiating peripheral from central positional vertigo with no gold standard in site. Accompanying central signs don’t help, since many BPPV patients actually do report diplopia, or sensory signs, show ataxia and worse. Why that?
In the end, any neurologist has to master his own set of diagnostic and therapeutic maneuvers and – when successful – be content with his own diagnosis.
In this session, we perform the following maneuvers for training:
- diagnostic pPPV test: Dix-Hallpike (in the original version)
- therapeutic pPPV maneuver: modified Epley
- diagnostic hPPV test: supine roll test aka McLure
- lateralization hPPV test: bow-and-lean, Asprella aka lying back
- therapeutic hPPV maneuver: barbecue (270° or 360°, I don’t care), log roll maneuver, Gufoni (there are at least 3 different descriptions of this)
We covered superior aka anterior canal in a previous session.