Man-machine interfacing based on ultrasound wearable technology for controlling upper limb prostheses
Lead Research Organisation:
Imperial College London
Department Name: Bioengineering
Abstract
Current state-of-the-art control methods for upper limb prostheses are based on muscle electrical activity detected with non-invasive electrodes (surface EMG). However, surface EMG has poor spatial resolution, is influenced by the skin-electrode interface, has a detection volume limited to few millimetres up to 1 centimetre depth (therefore not accessing deep muscles), and varies its characteristics as a consequence of fatigue and other physiological factors. These limitations pose important issues in conventional myo-control strategies for active prostheses, associated to an abandonment rate of approximately 50%. This project aims to investigate the usage of an alternative, clinically-viable and non-invasive approach -muscle ultrasound sensing and imaging --for detecting the motion of musculoskeletal structure sand establishing a neural interface between patients and prosthetic arms/hands. For this purpose, we will develop a wearable ultrasound system to detect and characterize the activity and elastic status of muscle structures and machine learning methods to map the ultrasound signals into commands for bionic limbs. Ultrasound techniques can penetrate deep in soft tissue (a few cm to15cm) with scalable spatial resolution (tens of microns to ~1mm), and have shown excellent sensitivity in detecting subtle local tissue motion. Recent advances in ultrafast ultrasound have enabled the detection of deep tissue motion at micrometre level to be detected at a temporal resolution <1 millisecond.
Hence ultrasound can provide a direct measure of muscle movement by image monitoring the entire muscle cross-sectional are a with very high temporal resolution, and is not influenced by the confounding factors affecting EMG recordings. Moreover, ultrasound systems can be miniaturized and therefore mounted as wearable devices. The project will develop for the first time ultrasound and signal processing technology for wearable man-machine interfacing and will translate these developments into clinical usability tests.
Ongoing work in the research group and the PhD aims.
The Neuromechanics and Rehabilitation Technology group at the Department of Bioengineering of Imperial College London, led by Prof. Dario Farina, focuses on electrophysiology techniques for the study of neural control of movement, bioelectrodes and biosignal processing, neurorehabilitation, active prostheses, human-machine interfaces, and motor neuron recordings in vivo. There search of the group has made major contributions to muscle electrophysiology and human-machine interfacing by developing concepts and techniques to fill the gap between the neural and biomechanical investigation of human movement. The Ultrasound Laboratory for Imaging and Sensing (ULIS), led by Professor Mengxing Tang, mainly focuses on developing new ultrasound imaging and sensing techniques for a wide range of biomedical applications.
Hence ultrasound can provide a direct measure of muscle movement by image monitoring the entire muscle cross-sectional are a with very high temporal resolution, and is not influenced by the confounding factors affecting EMG recordings. Moreover, ultrasound systems can be miniaturized and therefore mounted as wearable devices. The project will develop for the first time ultrasound and signal processing technology for wearable man-machine interfacing and will translate these developments into clinical usability tests.
Ongoing work in the research group and the PhD aims.
The Neuromechanics and Rehabilitation Technology group at the Department of Bioengineering of Imperial College London, led by Prof. Dario Farina, focuses on electrophysiology techniques for the study of neural control of movement, bioelectrodes and biosignal processing, neurorehabilitation, active prostheses, human-machine interfaces, and motor neuron recordings in vivo. There search of the group has made major contributions to muscle electrophysiology and human-machine interfacing by developing concepts and techniques to fill the gap between the neural and biomechanical investigation of human movement. The Ultrasound Laboratory for Imaging and Sensing (ULIS), led by Professor Mengxing Tang, mainly focuses on developing new ultrasound imaging and sensing techniques for a wide range of biomedical applications.
Planned Impact
The CDT students will help create solutions for amputees and people with debilitating conditions such as stroke and diabetes, reducing mortality and enabling them to live more satisfying, productive and fulfilling lives. These solutions, co-created with industry and people living with disabilities, will have direct economic and societal benefits. The principal beneficiaries are industry, P&O service delivery, people who need P&O devices, and society in general.
Industry
The novel methods, devices and processes co-created with users and industry will have a direct economic value to our industry partners (by the creation of IP, new products, and improved industry and academic links). Our CDT graduates will be the natural potential employees of our industry partners and for companies in the wider healthcare technology sector. This will help address the identified critical skills need and shortage leading to improvement in the UK's competitiveness in this rapidly developing and growing global market. The CDT outcomes will help UK businesses spread risk (because new developments are well founded) and more confidently enter new markets with highly skilled employees (CDT graduates).
P&O service delivery
Doctoral engineering graduates with clinical knowledge are needed to improve the deployment of advanced technologies in practice. Our main UK industry partner, Blatchford, stated: "As technology develops it will become easier for the end-user (the patient), but the providers (the clinicians) are going to need to have a higher level of engineering training, ideally to PhD level". The British Association of Prosthetists and Orthotists estimates that no more than ten practising P&O clinicians have a PhD in the UK. Long-term P&O clinical academic leadership will be substantially improved by the CDT supporting a select number of clinically qualified P&O professionals to gain doctorates.
Users
The innovation of devices, use of device and patient monitoring, and innovation approaches in LMIC should not only lead to improved care but also lower healthcare costs. Diabetes UK estimates that the total healthcare expenditure related to foot ulceration and amputation in diabetes was £1billion (2014-15), with 2/3 of this related to foot ulceration. Small innovations could lead to large cost savings if targeted at the right aspects of care (e.g. earlier adoption, and reducing device abandonment).
An ability to work is fundamental to a person's place in society and their sense of purpose and has a significant societal impact in all territories. This is perhaps greatest in LMIC where attitudes towards disability may still be maturing, and appropriate social care infrastructure is not always in place. In these cases, an ability to work is essential for survival.
Improved design approaches will impact on all users regardless of context, since the device solutions will better match local and individual user needs. Addressing issues related to prosthetic/orthotic device abandonment (e.g. cosmesis) and improved adherence should also lead to greater social participation. Improved device solutions will shift focus from what users "cannot do" to what they now "can do", and help progress attitudes towards acceptance of disability.
Societal
The majority of the global P&O users are of working age, and a key economic impact will be keeping users in work. The average age at amputation due to diabetes is just 52 in the USA but much younger in countries with less well-developed health care and trauma services (e.g. 38 in Iran). Diabetes UK reports that 35-50% of people are of working age at diagnosis and that there are around 70,000 foot ulcers in the UK, precursors to amputation. There is a similar concern for stroke survivors around a quarter of whom are of working age and are 2-3 times more likely to be out of work after eight years.
Industry
The novel methods, devices and processes co-created with users and industry will have a direct economic value to our industry partners (by the creation of IP, new products, and improved industry and academic links). Our CDT graduates will be the natural potential employees of our industry partners and for companies in the wider healthcare technology sector. This will help address the identified critical skills need and shortage leading to improvement in the UK's competitiveness in this rapidly developing and growing global market. The CDT outcomes will help UK businesses spread risk (because new developments are well founded) and more confidently enter new markets with highly skilled employees (CDT graduates).
P&O service delivery
Doctoral engineering graduates with clinical knowledge are needed to improve the deployment of advanced technologies in practice. Our main UK industry partner, Blatchford, stated: "As technology develops it will become easier for the end-user (the patient), but the providers (the clinicians) are going to need to have a higher level of engineering training, ideally to PhD level". The British Association of Prosthetists and Orthotists estimates that no more than ten practising P&O clinicians have a PhD in the UK. Long-term P&O clinical academic leadership will be substantially improved by the CDT supporting a select number of clinically qualified P&O professionals to gain doctorates.
Users
The innovation of devices, use of device and patient monitoring, and innovation approaches in LMIC should not only lead to improved care but also lower healthcare costs. Diabetes UK estimates that the total healthcare expenditure related to foot ulceration and amputation in diabetes was £1billion (2014-15), with 2/3 of this related to foot ulceration. Small innovations could lead to large cost savings if targeted at the right aspects of care (e.g. earlier adoption, and reducing device abandonment).
An ability to work is fundamental to a person's place in society and their sense of purpose and has a significant societal impact in all territories. This is perhaps greatest in LMIC where attitudes towards disability may still be maturing, and appropriate social care infrastructure is not always in place. In these cases, an ability to work is essential for survival.
Improved design approaches will impact on all users regardless of context, since the device solutions will better match local and individual user needs. Addressing issues related to prosthetic/orthotic device abandonment (e.g. cosmesis) and improved adherence should also lead to greater social participation. Improved device solutions will shift focus from what users "cannot do" to what they now "can do", and help progress attitudes towards acceptance of disability.
Societal
The majority of the global P&O users are of working age, and a key economic impact will be keeping users in work. The average age at amputation due to diabetes is just 52 in the USA but much younger in countries with less well-developed health care and trauma services (e.g. 38 in Iran). Diabetes UK reports that 35-50% of people are of working age at diagnosis and that there are around 70,000 foot ulcers in the UK, precursors to amputation. There is a similar concern for stroke survivors around a quarter of whom are of working age and are 2-3 times more likely to be out of work after eight years.
