The spin is mechanical, not neurological. Tiny calcium crystals normally sit above the balance loops in your ear. One breaks loose, drops into a loop, and now every head movement drags grit through fluid; your brain misreads it as violent rotation that is not happening ¹. About 85% of the time it is one specific loop, the posterior canal ².

The signature is unmistakable. Ten to forty seconds of the room spinning, triggered by rolling over in bed, tipping your head back at the sink, or looking up to a high shelf, then it fades. Only then. A one-move office test, the Dix-Hallpike, confirms which ear ³. The repositioning maneuver clears 60 to 80% of cases in a single try, versus 10 to 20% with a fake ⁴. Low vitamin D raises your odds of recurrence; correcting it lowers them ⁵.

Get the ear diagnosed once, then it is yours to repeat. For a first episode, have a clinician or vestibular physical therapist confirm which ear the crystal is in and walk you through the maneuver. After that you handle recurrences at home ².

The room can stop mid-maneuver. Many people feel the spin wind down on the second head turn, before they even sit up. By the next morning, rolling over just feels like rolling over. Within a week your partner stops asking how you are; within a month the braced posture and the low-grade exhaustion of constant vigilance relax with it ⁶. Recurrence is common, but the first cure is the expensive one. Every episode after that costs five minutes.