Estimating the time constant of pitch rVOR by separation of otoliths and semicircular canals contributions

G. Bertolini, C. J. Bockisch, D. Straumann, D. S. Zee, S. Ramat

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The rotational vestibulo-ocular reflex (rVOR) contributes to gaze stabilitization by compensating head rotational movements sensed by the semicircular canals (SCC). The CNS improves the performance of the horizontal rVOR through the so called velocity storage mechanism (VSM). However the properties of the VSM in response to pitch rotations are less well known. We recorded eye movements evoked by whole-body constant-velocity pitch rotations about an earth-horizontal, interaural axis in four healthy human subjects. Subjects were tumbled forward, and backward, at 60 deg/s for over one minute using a 3D turntable. In these conditions also the otoliths contribute to the perception of head rotation because they sense the changes in direction of the gravity vector. The vertical slow phase velocity (SPV) responses show the typical exponential decay of the rVOR and a residual, otolith-driven sinusoidal modulation with a bias. Here the estimates of the contributions coming from the otoliths and from the canals are based on a linear summation hypothesis. The time constants of the canal-driven vertical component of the SPV ranged from 6 to 9 seconds. These values are closer to those produced by the SCC alone than the typical 20 s produced by the VSM in the horizontal plane, confirming the relatively small contribution of the VSM to these vertical responses. We also show that the estimation method, while it may be not physiologically accurate, is easy to implement and leads to reliable results.

Original languageEnglish (US)
Title of host publicationProceedings of the 30th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS'08
PublisherIEEE Computer Society
Pages1060-1063
Number of pages4
ISBN (Print)9781424418152
DOIs
StatePublished - 2008
Event30th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS'08 - Vancouver, BC, Canada
Duration: Aug 20 2008Aug 25 2008

Publication series

NameProceedings of the 30th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS'08 - "Personalized Healthcare through Technology"

Other

Other30th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS'08
CountryCanada
CityVancouver, BC
Period8/20/088/25/08

ASJC Scopus subject areas

  • Computer Vision and Pattern Recognition
  • Signal Processing
  • Biomedical Engineering
  • Health Informatics

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