Title: Multi-electrode electromyography: developing electrical cross-sectional imaging of skeletal muscle.
Funder: Engineering and Physical Sciences Research Council

Abstract: Needle electromyography (EMG) is an essential diagnostic test in the investigation of patients with peripheral nerve and muscle disease. For conditions such as motor neuron disease, a relentlessly progressive degeneration of the motor system, it is the only diagnostic test available. However, current EMG technology has barely advanced in the past 50 years. EMG involves inserting a metal needle through the skin into a muscle, and recording the electrical activity produced by the muscle fibres. Diseases affecting the motor nerves or the muscle produce characteristic changes in this electrical activity. The signal is recorded from a single point at the needle tip, and herein lies the fundamental limitation of current technology. Since only a single recording surface is used, this 'single channel' recording consists of overlapping electrical signals from dozens of individual muscle fibres, and untangling these to work out how the muscle fibres are arranged within the muscle can be difficult. Furthermore, the volume of muscle sampled is tiny, meaning that in order to diagnose a widespread disease, such as motor neuron disease, the needle has to be repositioned several times within several muscles. This increases the pain for the patient and means that some studies can take over an hour to perform. Our proposal is to adapt and develop existing microfabrication techniques to produce a novel EMG electrode, of similar diameter to a conventional needle, which will record simultaneously from 64 points along the needle. This will allow the rapid and accurate localisation of each individual muscle fibre within the muscle without the need for needle movement, in effect producing an electrical cross-sectional image of the muscle. This will massively increase the accuracy of the test and significantly reduce the time taken. Our group consists of clinicians and basic scientists based within the Royal Victoria Infirmary, Newcastle and Newcastle University. We have already developed multi-electrodes for recording electrical activity from within the brain, using microfabrication facilities within Newcastle University. We will adapt these to record from human muscle, and will test these in human volunteers. We also have extensive experience in developing novel software to analyse the data from multi-channel recordings, and we will develop a suite of programs to display muscle structure and function in real-time. This will allow clinicians to view the results as they are collected allowing them to decide whether a diagnosis has been reached or if further muscles need to be studied. Our ultimate aim is to develop a prototype clinically applicable system which we will then develop in partnership with a commercial medical instrument company. There are approximately 100,000 EMGs performed each year in the UK. Even if our system reduces the time taken by ten minutes each, this will have a massive cost saving for the NHS, quite apart from the benefits to patients in terms of improved diagnosis and reduced discomfort. We believe that this technique is achievable, and will be as revolutionary for EMG as the development of magnetic resonance imaging has been for radiology.


Research activity codes: 4.1 DISCOVERY AND PRECLINICAL TESTING OF MARKERS AND TECHNOLOGIES
Health categories: MUSCULOSKELETAL;NEUROLOGICAL