6. Benign Paroxysmal Positional Vertigo (BPPV)
BPPV affects 64 out of 100 000 people per year. It is identified by short periods (less than a minute) of vertigo (you or the room spinning) when moving your head. The feeling of dizziness happens because crystals are moving within your inner ear.
The vestibular system consists of three semicircular canals, at right angles to each other. The semicircular canals transmit information about the direction your head is moving and how fast your head is moving (e.g. turning and shaking your head when saying “No”).
The oolith organs lie at the base of the semicircular canals. They send information about flexion/extension (nodding yes) movement and speed of movement. Octonia are calcium carbonate crystals on the oolith organ.
BPPV is when these crystals are knocked out of place keep moving from one position to the next. These crystals can move into a semicircular canal (canalisthiasis) or stick to the cupula (cupulolisthiasis). This can happen after head trauma, labyrinthitis or a drop in the blood supply to the vestibular system.
Episodes of vertigo are then triggered by lying down, rolling, bending or looking up. This explains the feeling of spinning and nausea when turning in bed, bending over to pick something up, looking up when hanging washing or rinsing your hair. An episode only lasts a few seconds, but the feeling of unsteadiness can linger for days.
An episode would follow a head injury, ear infection or having held a strange head position for a long time, like sitting with your head held back at the hair salon. BPPV is more common in women, because of the lower bone mineral density.