BPPV — Positional Vertigo with Dix-Hallpike

A 58-year-old woman presents with brief episodes of intense rotatory vertigo lasting 20–40 seconds triggered by rolling over in bed and looking up. She denies hearing loss, tinnitus, or aural fullness. The Dix-Hallpike maneuver on the right side reproduces short-latency (2–5 second), geotropic up-beating torsional nystagmus lasting <60 seconds with fatigability on repeat testing. Pure-tone audiometry is completely normal with symmetric thresholds. The clinical findings shown in the diagram at **A** are consistent with right posterior canal BPPV. Which of the following BEST describes the pathophysiological mechanism underlying this patient's vertigo?