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Persistence of perilymph fistula mechanism in a completely paretic posterior semicircular canal
  1. C Helmchen1,
  2. E Gehrking2,
  3. S Gottschalk3,
  4. H Rambold1
  1. 1Department of Neurology, University of Lübeck, Ratzeburger Allee 160, D-23538 Lübeck
  2. 2Department of Otolaryngology, University of Lübeck
  3. 3Department of Neuroradiology, University of Lübeck
  1. Correspondence to:
 Professor C Helmchen
 Department of Neurology, University of Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany;


The three dimensional eye movements (search coil technique) of a patient with a completely paretic left posterior semicircular canal as a result of a perilymph fistula (PLF) were studied. The patient still exhibited pressure induced nystagmus that obeyed Ewald’s first law. This finding cannot be explained by otolith stimulation, but might indicate that PLF mechanisms either persist in canal plugging or act on the ampulla by directly deflecting the cupula.

  • AC, anterior semicircular canal
  • CEMP, click evoked myogenic potentials
  • HC, horizontal semicircular canal
  • PC, posterior semicircular canal
  • PLF, perilymph fistula
  • SVV, subjective visual vertical
  • VOR, vestibulo-ocular reflex
  • perilymph fistula
  • canal paresis
  • posterior semicircular canal

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  • Competing interests: none declared