Micro-EMG: A novel multielectrode system for intramuscular imaging
Research type
Research Study
Full title
Micro-EMG: A novel multielectrode system for intramuscular imaging of human motor units
IRAS ID
280391
Contact name
Roger Whittaker
Contact email
Sponsor organisation
NuTH (NJRO)
Clinicaltrials.gov Identifier
Duration of Study in the UK
1 years, 1 months, 31 days
Research summary
Needle electromyography (EMG) is an essential diagnostic test in the investigation of patients with peripheral nerve and muscle disease. The technique involves placing a fine metal needle through the skin into a muscle, and recording the electrical activity that the muscle generates. Current EMG needles record from a single recording surface at the tip of the needle, meaning that it needs to be moved to several places within the muscle in order to record enough activity to make a diagnosis.
We have developed a completely new multi-electrode electromyography system (MicroEMG). This new device consists of a very thin (20microns thick) flexible electrode that is bonded to the outside of a standard EMG needle and has 32 recording points along its length. It records muscle activity from each of these recording points in the muscle at once. We expect this will increase the sensitivity of the technique in diagnosing muscle disease, reduce the time taken, and be more comfortable for patients.
We intend in the future to perform a head-to-head comparison of conventional EMG vs MicroEMG in the diagnosis of patients with nerve and muscle diseases. However, we know that the recorded signals of the two techniques will differ purely because they are recorded from different positions within the muscle. This potentially biases any head-to-head comparison. In order to avoid this, we first need to understand the relationship between the recorded signals using each technique; i.e. which features are the same and which are different. For example, if we were to arbitrarily take the total size of the signal as the primary outcome measure in a head-to-head trial, microEMG would almost certainly come out as favourable simply because it records from a greater volume of tissue than conventional EMG. However, the total size of the signal may not actually be of any benefit in terms of achieving a more accurate diagnosis. An analogy would be looking at the muscle through a light microscope and an electron microscope. The muscle will certainly look ‘bigger’ using the electron microscope, but it does not necessarily mean that this is a better diagnostic tool than light microscope (which is what is actually used in clinical practice). It is only by understanding the relationship between the signals recorded by conventional EMG and microEMG that we can decide which features of the recorded signals should be used as an unbiased primary outcome measure in any subsequent head-to-head trial. This project seeks to do this.
We will recruit healthy controls as well as patients with a known diagnosis of diseases known to affect either the nerves or the muscles who typically would be investigated using conventional EMG. The diseases will be motor neuron disease (MND), Sarcopenia, Post-polio Syndrome (PPS), and Myasthenia gravis. Each patient will undergo recordings from identical muscles using both conventional EMG and microEMG on a single occasion. This will allow us to compare the intramuscular electrical signal patterns obtained by conventional EMG and MicroEMG in both healthy and diseased muscles, and hence determine which of these patterns are suitable as a future trial outcome measure.REC name
North of Scotland Research Ethics Committee 1
REC reference
22/NS/0097
Date of REC Opinion
30 Jul 2022
REC opinion
Favourable Opinion