Experimental Validation Of A Clinical Indicator Of Utricular Function.
Funder
National Health and Medical Research Council
Funding Amount
$198,689.00
Summary
The vestibular system is responsible for our sense of balance, it is located in the inner ear and is responsible for maintaining posture and helping an organism to make appropriate eye movements when the head moves. Damage to the vestibular system by disease or accident is extremely debilitating for a patient. A chief goal of our research program is to develop simple tests of the vestibular system that can be used in the clinic to diagnose vestibular disorders. Most present clinical tests only t ....The vestibular system is responsible for our sense of balance, it is located in the inner ear and is responsible for maintaining posture and helping an organism to make appropriate eye movements when the head moves. Damage to the vestibular system by disease or accident is extremely debilitating for a patient. A chief goal of our research program is to develop simple tests of the vestibular system that can be used in the clinic to diagnose vestibular disorders. Most present clinical tests only test the part of the vestibular system that responds to angular rotations (the semicircular canals). There are few good tests that can reliably diagnose problems concerned with sensed position (the otoliths). Recent evidence from human studies has shown that by delivering small electrical currents (galvanic stimulation) via electrodes located on the surface of the skin behind the ears, a characteristic pattern of eye movement occurs. Our hypothesis is that the distinctive pattern of eye movement produced is a result of otolith stimulation. The aim of this project is to determine exactly how these small currents produce the eye movements and if these eye movements are in fact mediated by the otoliths. To determine the physiology that underlies these types of responses we are unable to conduct these experiments in humans. Our present program will therefore use both behavioural and physiological experiments on guinea pigs to test our hypotheses about galvanic stimulation and otolith function. The significance of this work lies in that it will lead to a new way of evaluating the function of the gravity sensing part of the human vestibular system which appear to be uniquely important for patients with balance problems.Read moreRead less
Testing Of Vestibular Function By Active Head Movements.
Funder
National Health and Medical Research Council
Funding Amount
$180,509.00
Summary
The vestibular system of the inner ear is responsible for our sense of balance and for maintaining clear vision and stable posture during head movements. This complex interdependent sensory system is comprised of three paired semicircular canals for sensing head rotations and two paired otolith organs for sensing head position and linear movements of the head. A major goal of our research programs is to develop simple tests which can be used in the clinic or at the bedside to diagnose specific d ....The vestibular system of the inner ear is responsible for our sense of balance and for maintaining clear vision and stable posture during head movements. This complex interdependent sensory system is comprised of three paired semicircular canals for sensing head rotations and two paired otolith organs for sensing head position and linear movements of the head. A major goal of our research programs is to develop simple tests which can be used in the clinic or at the bedside to diagnose specific deficits of each vestibular sensory region. Most present clinical tests only test the part of the system concerned with horizontal head rotations but there are many other sensory regions in the inner ear whose functional status needs to be evaluated, especially those regions concerned with signalling linear head movements and head position - the otolith sensory regions. The usual principle in vestibular testing is to move the person's head and measure the eye movement which occurs in response to that passive movement. One of our recent observations suggest that it may be possible to measure vestibular functioning during active head movements. Active testing does not require expensive, invasive testing systems and could be carried out in the clinic. This project will compare the eye movement response to active and passive head movements in the same patients. We will test both the angular and linear sensing systems by asking patients to rotate their head or slide it laterally, recording the head movement stimulus and eye movement response. Two groups of patients will be studied; those who have recovered well and those who are poorly recovered after unilateral vestibular loss. The outcome will, we hope, be safe simple low cost tests which will evaluate the functional status of all the inner ear sensory regions and yet be clinically practical. They may provide the answer as to why some patients do not recover well after unilateral loss whereas others do.Read moreRead less
Behavioural And Physiological Tests Of Clinical Indicators Of Vestibular Function.
Funder
National Health and Medical Research Council
Funding Amount
$205,500.00
Summary
Part of the inner ear is responsible for our sense of balance and for maintaining clear vision and stable posture. Recurring vertigo attacks and persistent imbalance can disrupt the most productive years of patients' lives and balance-related falls account for more the half of accidental deaths in the elderly. Despite this most doctors find dizziness difficult to diagnose and impossible to treat, so specialist Balance Disorders Clinics see many patients a year but still have very long waiting ti ....Part of the inner ear is responsible for our sense of balance and for maintaining clear vision and stable posture. Recurring vertigo attacks and persistent imbalance can disrupt the most productive years of patients' lives and balance-related falls account for more the half of accidental deaths in the elderly. Despite this most doctors find dizziness difficult to diagnose and impossible to treat, so specialist Balance Disorders Clinics see many patients a year but still have very long waiting times. There is then clearly a major need to improve the understanding and the treatment of dizzy patients and improvement will come about through scientific understanding of vestibular dysfunction, and technological realization of improvements in the assessment and treatment of patients. This project seeks to identify whether 3 simple new indicators of balance function are valid, using tests on guinea pigs to understand the way in which they work.Read moreRead less