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Optical sensors for mechanomyography and tissue chromophores

Ljungberg, Emil LU (2013) PHYL01 20132
Atomic Physics
Department of Physics
Abstract
The mechanomyogram (MMG) is a mechanical oscillations observable on the surface of the skin as a muscle contracts. Measurement of the MMG utilizing contact sensors with a weight greater than 6 g has proved to interfere with the measurement. Use of optical displacement sensors without direct contact to the skin would remove this deficiency. A Michelson interferometer, an intensity shift set-up and a configuration able of measuring both MMG and tissue oxygenation dynamics simultaneously were all evaluated in regard to their precision, easy of use and efficacy. The results were analysed using the fast Fourier transform (FFT) and the continuous wavelet transform (CWT) A regular Michelson interferometer proved to be unsuited for measuring... (More)
The mechanomyogram (MMG) is a mechanical oscillations observable on the surface of the skin as a muscle contracts. Measurement of the MMG utilizing contact sensors with a weight greater than 6 g has proved to interfere with the measurement. Use of optical displacement sensors without direct contact to the skin would remove this deficiency. A Michelson interferometer, an intensity shift set-up and a configuration able of measuring both MMG and tissue oxygenation dynamics simultaneously were all evaluated in regard to their precision, easy of use and efficacy. The results were analysed using the fast Fourier transform (FFT) and the continuous wavelet transform (CWT) A regular Michelson interferometer proved to be unsuited for measuring oscillations with an amplitude greater than =4. Demodulation of signals exceeding this limit requires cumbersome analysis methods that would not be practically feasible in a clinical set-up. By measuring the light reflected from an oscillating target, a second simpler set-up was able to measure the frequency and amplitude of a tuning fork with high precision. Measurements on biceps bracii was performed but no clear results were found. A set-up combining MMG and tissue chromophores was realised with three optical fibres attached to the skin. The haemoglobin oxygenation dynamics was successfully measured during contraction and relaxation of the biceps brachii but no MMG signal could be deduced. The outcome of this thesis suggest that further research is required to investigate the possibility of designing a set-up able to measure both MMG and haemoglobin oxygenation dynamics with high precision. This would enable a detailed study of muscle dynamics which have not been done before. (Less)
Please use this url to cite or link to this publication:
author
Ljungberg, Emil LU
supervisor
organization
course
PHYL01 20132
year
type
M2 - Bachelor Degree
subject
language
English
id
4238291
date added to LUP
2014-01-09 12:59:59
date last changed
2014-01-14 12:19:13
@misc{4238291,
  abstract     = {The mechanomyogram (MMG) is a mechanical oscillations observable on the surface of the skin as a muscle contracts. Measurement of the MMG utilizing contact sensors with a weight greater than 6 g has proved to interfere with the measurement. Use of optical displacement sensors without direct contact to the skin would remove this deficiency. A Michelson interferometer, an intensity shift set-up and a configuration able of measuring both MMG and tissue oxygenation dynamics simultaneously were all evaluated in regard to their precision, easy of use and efficacy. The results were analysed using the fast Fourier transform (FFT) and the continuous wavelet transform (CWT) A regular Michelson interferometer proved to be unsuited for measuring oscillations with an amplitude greater than =4. Demodulation of signals exceeding this limit requires cumbersome analysis methods that would not be practically feasible in a clinical set-up. By measuring the light reflected from an oscillating target, a second simpler set-up was able to measure the frequency and amplitude of a tuning fork with high precision. Measurements on biceps bracii was performed but no clear results were found. A set-up combining MMG and tissue chromophores was realised with three optical fibres attached to the skin. The haemoglobin oxygenation dynamics was successfully measured during contraction and relaxation of the biceps brachii but no MMG signal could be deduced. The outcome of this thesis suggest that further research is required to investigate the possibility of designing a set-up able to measure both MMG and haemoglobin oxygenation dynamics with high precision. This would enable a detailed study of muscle dynamics which have not been done before.},
  author       = {Ljungberg, Emil},
  language     = {eng},
  note         = {Student Paper},
  title        = {Optical sensors for mechanomyography and tissue chromophores},
  year         = {2013},
}