Off-Axis Head Rotation Test of Otolith Function [ 2001 - 2003 ]

Research Grant

Researchers: Dr Swee Aw (Principal investigator)

Brief description Combined linear and angular head movements are integral components of our natural head movements. The vestibular sensory apparatus in the labyrinth of the inner ear, which comprises three semicircular canals and two otoliths acts as an inertial guidance system during head motion. The vestibular sensors mediate the angular and linear vestibulo-ocular reflexive eye movements imperative to stabilise vision during the head motions. However, it is unclear how these responses to sudden linear and angular motion in three dimensions are combined and processed. Diseases of the inner ear can produce incapacitating visual and balance disturbances, yet the normal function of some of the inner ears receptors, in particular the otoliths, cannot be easily tested. Clinical evidence has shown that patients with incapacitating attacks of vertigo can have impairment of either or both the semicircular canals and the otoliths. The aim of this project is to measure quantitatively the semicircular canal-otolith response to transient, high-acceleration combined linear-angular head movements to find a reliable way to test the otolith function. Based on physiological principles and my preliminary experiment, we plan to use an off-axis head rotation procedure, a three-dimensional eye movement recordings and vector analysis technique to assess the linear and angular vestibulo-ocular reflex response from the otoliths and semicircular canals in the labyrinth. The practical significance of answers to these questions is that they will characterise the combined linear and angular vestibulo-ocular reflex responses that stabilise vision during transient head movements. It will provide us with a greater understanding of the visual disturbance that patients experienced during these kinds of head movements following vestibular disease or surgery. Measurement of the linear vestibulo-ocular reflex may also provide a diagnostic test of otolith function clinically in disease states.

Funding Amount $AUD 301,018.36

Funding Scheme NHMRC Project Grants

Notes Standard Project Grant