👂 BPPV Otolith Crystal Dislodgement Simulator

Utricle Otoconia Break Free From the Macula

Aging or trauma loosens calcium carbonate crystals from their gel bed.

• CaCO3: Crystal material (calcite otoconia)
• 3–30 µm: Typical size (per crystal)
• Age / trauma: Common cause (degeneration of macula)
• ~2.4%: Prevalence (lifetime risk)

Why crystals detach

Placeholder: gel matrix degeneration frees otoconia over time.

Loose Crystals Drift Into the Posterior Canal

Gravity pulls dislodged debris into the most dependent canal.

• Posterior: Most affected canal (~90% of cases)
• Utricle → canal: Migration path (via common crus)
• Free clot: Debris form (canalithiasis)
• Seconds: Onset delay (after head shift)

Migration path

Placeholder: crystals settle by gravity into the canal arc.

Endolymph Drag Bends the Cupula Off-Axis

Crystal weight in the canal creates abnormal fluid drag on the cupula.

• Motion sensor: Cupula role (normally symmetric)
• Heavy debris: Deflection cause (cupulolithiasis variant)
• False: Signal type (no true rotation)
• 1–5 s: Latency (before nystagmus)

Fluid mechanics

Placeholder: crystal mass amplifies endolymph flow on tilt.

Position Change Triggers Spinning Vertigo

Head tilt produces brief but intense rotational vertigo and nystagmus.

• <60 s: Duration (per episode)
• Head tilt: Trigger (rolling in bed, looking up)
• Nystagmus: Hallmark sign (torsional-upbeating)
• Vertigo: Symptom (spinning sensation)

Clinical picture

Placeholder: brief severe vertigo follows specific head movements.

Canalith Repositioning Guides Crystals Home

Sequential head maneuvers move debris back to the utricle.

• Epley: Standard maneuver (canalith repositioning)
• ~80%: Success rate (after one session)
• Gravity-guided: Mechanism (sequential rotation)
• ~15%: Recurrence (within one year)

Treatment logic

Placeholder: gravity carries crystals out via timed head turns.

Placeholder: maneuvers restore normal cupula function quickly.