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Control of upper-limb functional neuromuscular electrical stimulation

Control of upper-limb functional neuromuscular electrical stimulation
Control of upper-limb functional neuromuscular electrical stimulation
Functional electrical stimulation (FES) is the name given for the use of neuromuscular electrical stimulation to achieve patterns of induced movement which are of functional benefit to the user. System are available that use FES to aid persons who have suffered an insult to the motor control region of the brain and been left with movement impairment.

The aim of this research was to investigate methods of providing an FES system that could have a beneficial effect in restoring arm function. The techniques for applying upper-limb stimulation are well established, however the methods of controlling it to provide functional use remain lacking. This is because upper-limb movement can be difficult to measure and quantify as the starting point for any movement may not be well defined. Moreover the movements needed to complete a useful function such as reaching and grasping requires the coordinated control of a number of muscle groups, and that relies on being able to track the position of the limb. Effective control of FES for the arm requires reliable feedback about the position and state of the limb.

Electromyograms (EMG) are a measure of the very small electrical signals that are emitted whenever a muscle is ‘fired’ to move. EMG can be used to detect muscle activity and so can be a useful feedback control input. It does however have a number of drawbacks that this research sought to address by combining the method with external motion sensors. The intension had been to use the motion sensors to track the position of the limb and then use the EMG measurements to detect the wearer’s movements. FES could then be used to assist the wearer in making a desired movement. Initial studies were done to separately investigate the motion sensing and the EMG measurement components of the system. However before these could be combined a more interesting observation was made relating to bioimpedance.

A study of bioimpedance measurements found a relationship between tissue impedance changes and muscle activity. Different methods for measuring bioimpedance where investigated and the results compared, before a practical technique for capturing measurements was developed and demonstrated. A new set of test equipment was made using these finding. Subsequent results using this equipment were able to demonstrate that bioimpedance measurement could be taken from a limb while FES was being used, and that these measurement could be used as a feedback signal to control the FES to maintain a target limb position.

This work forms the basis of a novel approach to the control of FES that uses feedback from the user’s limb to determine the position of the limb in free space without need for additional sensors.
University of Southampton
Lane, Rodney
2c1cf022-2993-48a3-b23d-2ac4c635e9bf
Lane, Rodney
2c1cf022-2993-48a3-b23d-2ac4c635e9bf
Chappell, Paul H
17671350-2bc1-4574-af55-239b7dcb20ab

Lane, Rodney (2016) Control of upper-limb functional neuromuscular electrical stimulation. University of Southampton, Doctoral Thesis, 264pp.

Record type: Thesis (Doctoral)

Abstract

Functional electrical stimulation (FES) is the name given for the use of neuromuscular electrical stimulation to achieve patterns of induced movement which are of functional benefit to the user. System are available that use FES to aid persons who have suffered an insult to the motor control region of the brain and been left with movement impairment.

The aim of this research was to investigate methods of providing an FES system that could have a beneficial effect in restoring arm function. The techniques for applying upper-limb stimulation are well established, however the methods of controlling it to provide functional use remain lacking. This is because upper-limb movement can be difficult to measure and quantify as the starting point for any movement may not be well defined. Moreover the movements needed to complete a useful function such as reaching and grasping requires the coordinated control of a number of muscle groups, and that relies on being able to track the position of the limb. Effective control of FES for the arm requires reliable feedback about the position and state of the limb.

Electromyograms (EMG) are a measure of the very small electrical signals that are emitted whenever a muscle is ‘fired’ to move. EMG can be used to detect muscle activity and so can be a useful feedback control input. It does however have a number of drawbacks that this research sought to address by combining the method with external motion sensors. The intension had been to use the motion sensors to track the position of the limb and then use the EMG measurements to detect the wearer’s movements. FES could then be used to assist the wearer in making a desired movement. Initial studies were done to separately investigate the motion sensing and the EMG measurement components of the system. However before these could be combined a more interesting observation was made relating to bioimpedance.

A study of bioimpedance measurements found a relationship between tissue impedance changes and muscle activity. Different methods for measuring bioimpedance where investigated and the results compared, before a practical technique for capturing measurements was developed and demonstrated. A new set of test equipment was made using these finding. Subsequent results using this equipment were able to demonstrate that bioimpedance measurement could be taken from a limb while FES was being used, and that these measurement could be used as a feedback signal to control the FES to maintain a target limb position.

This work forms the basis of a novel approach to the control of FES that uses feedback from the user’s limb to determine the position of the limb in free space without need for additional sensors.

Text
R_Lane_PhD_thesis_2016_25-08-16 - Version of Record
Restricted to Repository staff only until 30 November 2022.
Available under License University of Southampton Thesis Licence.

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Published date: November 2016

Identifiers

Local EPrints ID: 419062
URI: http://eprints.soton.ac.uk/id/eprint/419062
PURE UUID: 263ebbbd-aacf-42ed-9535-c805fec5adab

Catalogue record

Date deposited: 28 Mar 2018 16:30
Last modified: 17 Dec 2019 17:30

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