Benign paroxysmal positional vertigo (BPPV) is a mechanical disorder of the semicircular canals of the inner ear.  There are three of these ring-shaped canals in each ear, along with two other sensors that are able to sense gravity because they are capped by a bed of relatively heavy crystals.  It is the shifting of these crystals on the gravity sensor that give you the sensation of going up and down in an elevator, or let you know when your head is tilted.  The problem is that all of the canals and the gravity sensors are interconnected by fluid pathways, so if these gravity-sensor crystals become dislodged, they can migrate into other parts of the ear.  

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How long do spells last?

Earlier blog pages have discussed the different feelings of dizziness that the inner ear can generate:  spinning, tilting or rocking, and elevator sensations.  The most common sensation indicating an inner ear problem is a feeling of whirling.  The inner ear has three sensors for spinning, the semicircular canals.  Because your head is firmly connected to your neck, every time you move your head on your neck, the head rotates to some degree.  It rotates in three-dimensional space, so three sensors can fully detect any rotation.  There are three major directions of rotations:  yaw, which is horizontal turning back and forth (detected by the horizontal semicircular canals);  pitch, tipping or nodding the head up and down (detected by the vertical semicircular canals);  and roll, tilting the head so the ear tips down toward the shoulder on either side (detected by the otolith organs).  Natural head turns tend to mix the various directions (like looking up and to the side for example), so all of the sensors in both ears are being used to feel and respond to these motions. 

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What triggers your dizzy spells?

Some spells come on out of the blue with no warning at all.  Others can be set off by something you do, or something you encounter—a trigger.  Spells with triggers are more likely to be benign, meaning that they often do not harm the ear.  Spells that come on without any warning are more likely to be damaging. 

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