Dr. Purcell has the most extensive diagnostic and treatment protocols for canalith repositioning chairs in the world. Whereas most phsyicians and patients peforming internet research believe there are only a few different eye movements driven by dislodged otoliths in the inner ear, Dr. Purcell has identified a very large series of potential eye movement patterns. These nystagmus patterns not only aid in the diagnosis of complex BPPV but also more accurate and effective treatment protocols. The orientation of the vestibular labyrinth as it sits positioned in the temporal bone of the patient is often not propely understood by technicians or physicians performing Dix-Hallpike and Epley manuevers. This is often more of an issue when patients are being tested on canalith repositioning chairs. These eye movement patterns below were collected on the Vesticon Epley Omniax Chair over a series of 20,000 patients. 


Y - Yaw

P - Pitch

UF - Utricular Fugal

UP - Utricular Pedal

 +   excitatory response

-   inhibitory response

cw - Clockwise nystagmus

ccw - Counterclockwise nystagmus

Up arrow - Upbeat nystagmus

Down arrow - Downbeat nystagmus

RB - right beat

LB - left beat

Br - barrel roll

Dix - Dix- Hallpike

AD - right ear

AS - left ear

SUP - supine position

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7625 Mesa College Drive

San Diego, CA 92111

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