What mechanisms in Benign Paroxysmal Positional Vertigo (BPPV) lead to a spinning feeling in the head?

Benign Paroxysmal Positional Vertigo (BPPV) is a condition where small crystals, called otoliths, become dislodged in the inner ear. These crystals normally help with balance by telling the brain how the head is moving. However, if they move into the wrong part of the ear, they give the brain mixed signals.

How It Works:

1. Normal Function: In a healthy ear, otoliths stay in one area and help sense gravity and movement.
2. Dislodgement: In BPPV, these crystals move into the semicircular canals, which are like tubes in your ear that help with balance.
3. Mixed Signals: When you move your head, these loose crystals make the fluid in the canals move in unusual ways, sending wrong messages to the brain.
4. Spinning Sensation: The brain gets confused by these mixed signals, leading to dizziness or a spinning feeling, especially when changing positions.

BPPV is usually not serious but can be very uncomfortable. It often happens when you turn your head or lie down. Understanding that it is caused by these tiny crystals can help make sense of why the world feels like it’s spinning.