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Title: Acceleration and vestibular mechanisms : a study of the interaction of angular and linear accelerations on human vestibular mechanisms
Author: Bodin, Michael A.
Awarding Body: University of Glasgow
Current Institution: University of Glasgow
Date of Award: 1970
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Recent developments in high performance aviation and manned space flight have added a considerable impetus to the need for a better understanding of the behavior of the Vestibular System. The stresses imposed by these environments may affect the balance mechanisms with important implications for the human traveller. This is the practical background against which the present study is set, but the work itself is essentially of an academic and theoretical nature. This is the practical background against which the present study is set, but the work itself is essentially of an academic and theoretical nature. The primary topic of this thesis is the interaction of linear and angular accelerations, studied under laboratory (simulated) circumstances, on human vestibular mechanisms. Theoretical and practical background studies of other experimenters, relevant to this topic, are reviewed. A series of differing experiments are described which examine the responses to interacting angular and linear accelarations, on human subjects, first during and then after rotation about each of the three orthogonal body axes: yaw, pitch and roll. Responses were compared both when the rotation axis was horizontal and when it was vertical; also, following rotation, when subjects were tilted to various different positions immediately after stopping. Two main findings emerged: (i) During rotation a sustained unidirectional compensatory nystagmic response was present when the rotation axis was horizontal but not when it was vertical. (ii) Following turning both the rate of decay of after sensations and nystagmus were increased, either when the axis of rotation was horizontal (compared with when it was vertical), or when the subjects were moved from the plane of rotation after stopping. These observations are discussed with particular emphasis on possible underlying machanisms which might have brought them about. It is concluded that a direct action of linear acceleration on the dynamic behavior of the peripheral end-organ is unlikely, and a central interaction mechanism more probable. The nature of such a mechanism is considered. Simple addition/substraction, proportional change, or alteration in 'gain' theories are rejected, and a theoretical equation which is a complex variable, exponential in general form, proposed instead. Reasons for this given, and a simple mathematical model postulated. Some practical implications of the experimental observations, irrespective of the underlying mechanism, are briefly mentioned.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available