Clinical case · foundation

Positional vertigo with a normal CDP

Vignette

A 58-year-old woman reports brief (10–20 second) episodes of spinning vertigo provoked by rolling over in bed and looking up. She had a single longer episode of vertigo when the symptoms first began two weeks ago, but since then the attacks have been strictly positional and brief. Bedside Dix-Hallpike to the right elicits upbeating-torsional nystagmus and reproduces her vertigo, with a latency of ~5 seconds and a duration of ~20 seconds.

CDP findings

SOT pattern vs normal
BPPVage norm 700255075100EQS93C1EO ·F93C2EC ·F87C3EO ·F·Sw85C4EO ·Sw65C5EC ·Sw63C6EO ·Sw·Sw
MCT — medium-amplitude backward translation
platform136 ms-100-500+50+100COP mm0200400600800100012001400BPPV · backward · medium
ADT — sway energy across five trials per direction
sway energy025507510058T150T238T338T430T5Toes upadapting65T149T239T333T434T5Toes downadapting

Single-best-answer

Her CDP is performed in the supine recovery period and is essentially normal. How should this be interpreted?

Teaching point. BPPV (Bárány Society 2015) is diagnosed by positional testing. CDP is typically near-normal between positional attacks and a normal CDP does not exclude BPPV. The Epley manoeuvre is first-line treatment for posterior canal BPPV.

References