Projects / Programmes
Decomposition of compound muscle action potentials
| Code |
Science |
Field |
Subfield |
| 2.06.10 |
Engineering sciences and technologies |
Systems and cybernetics |
Medical informatics |
| Code |
Science |
Field |
| B115 |
Biomedical sciences |
Biomechanics, cybernetics |
| Code |
Science |
Field |
| 2.06 |
Engineering and Technology |
Medical engineering
|
motor evoked potentials, decompostion, motor cortex stimulation, muscle stimulation, H reflexes
Researchers (21)
Organisations (3)
Abstract
Compound muscle action potential (CMAP) is sum of motor unit action potentials (MUAPs) in the muscle, elicited by electrical or mechanical stimulation of nerves and muscles or transcranial magnetic stimulation (TMS) of motor cortex. CMAP analysis is routinely applied in clinical and neurophysiologic studies to non-invasively assess the functional status of a human motor system in vivo, to evaluate motor tract integrity and quantify responses of neuromuscular circuits to training, rehabilitation and degeneration due to various neuromuscular disorders. Despite this wide use of CMAP analysis, no technique exists that supports decomposition of CMAP to contributions of individual motor units. As result, methodologies for motor unit differentiation, accurate assessment of motor unit number and type in the investigated muscle and selective motor unit monitoring in stimulated conditions are largely lacking. For the same reasons, the order of motor unit recruitment in different stimulation protocols is largely unknown, whereas the neural mechanisms behind the observed temporal variability of CMAPs are still poorly understood.
In this project, we propose to design computer-aided techniques for decomposition of CMAPs to contributions of different motor units. This will open numerous possibilities for novel analysis of evoked potentials with technology of non-invasive multichannel recordings of skeletal muscles, so called high-density electromyograms (hdEMG). Advanced procedures will be used to quantify the accuracy of CMAP decomposition and control the quality of the extracted information.
We will demonstrate the potential of developed techniques in three carefully selected demonstrators. The first one will analyse the CMAPs induced by TMS in order to illuminate short interval intracortical inhibition and facilitation and, thus, quantify the neural mechanisms of the excitability of primary motor cortex. The second demonstrator will apply the advanced analysis to CMAPs, elicited by electrical stimulation of nerves and skeletal muscles and will aim at improving our understanding of differences between fast-twitch and slow-twitch motor units in different use-case scenarios. It will also foster the assessment of motor excitability in post-activation potentiation and extend our understanding of potentiation-fatigue relationship. This is foreseen to have a great impact on the design of trainings in many different sports and rehabilitations after injuries. The third demonstrator will complement the second one and will conduct advanced analysis of H reflexes in order to provide better understanding of peripheral motor neuron excitability modulation in different measuring conditions.
Significance for science
Large number of scientific publications and applications have clearly demonstrated high potential of compound muscle action potential (CMAP) analysis and its relevance for the scientific community.
The proposed project activities are expected to greatly boost the interpretation of CMAPs as we will aim to efficiently separate the two classes of information that are embedded in CMAPs. The first class consists of motor unit action potential (MUAP) shapes that are greatly influenced by the volume conductor and properties of EMG acquisition system. As such, they are subject to large inter-subject and inter-measurement variability. The second class of information contains the motor unit firing and recruitment patterns. Up to now, the first class of information (MUAP shapes) has been largely analysed on a global level, ignoring the blurring effects of volume conductor, whereas the second class of information was more or less unavailable.
The lack of profound feedback on motor unit behaviour also limited the efficiency of stimulation fine-tuning and adaptation to individual person, as well as objective comparison of different stimulation protocols. The proposed project is, therefore, expected to have a profound effect also on the optimization of various stimulation devices and protocols and on promotion of non-invasive motor excitability investigation techniques in general. By providing the objective and highly detailed measures of CMAP properties, the project will also likely contribute to strengthening the interactions between technological and neurophysiological innovations.
On a long term, new neurophysiological findings, enabled by the proposed new methodology will boost the incorporation of new knowledge into available technical solutions as well as into neurological, kinesiological and rehabilitation procedures. All these positive effects will be additionally supported by the proposed strict control of quality of extracted information from CMAP.
Moreover, the project will clarify, on the level of individual motor neurons, the applicability and the potential of the proposed new methodology in the fields of a) cortical facilitations and inhibitions by transcranial magnetic stimulation (TMS), b) M wave analysis and its use in studies of post-activation potentiation in skeletal muscles and c) in studies of H reflex modulations. All three aforementioned analyses are highly relevant in the fields of basic neurophysiology, neurology, rehabilitation and sport sciences. Therefore, the three proposed demonstrators have been carefully selected to maximize the scientific and socio-economic outreach of the proposed project. Noteworthy, the very same CMAP decomposition concepts can easily be extended to numerous other stimulation scenarios such as analysis of F waves, for example.
Finally yet importantly, solving aforementioned methodological limitations will have a huge impact on neurophysiological community, contributing considerably to the visibility and promotion of Slovenian research excellence.
Significance for the country
Large number of scientific publications and applications have clearly demonstrated high potential of compound muscle action potential (CMAP) analysis and its relevance for the scientific community.
The proposed project activities are expected to greatly boost the interpretation of CMAPs as we will aim to efficiently separate the two classes of information that are embedded in CMAPs. The first class consists of motor unit action potential (MUAP) shapes that are greatly influenced by the volume conductor and properties of EMG acquisition system. As such, they are subject to large inter-subject and inter-measurement variability. The second class of information contains the motor unit firing and recruitment patterns. Up to now, the first class of information (MUAP shapes) has been largely analysed on a global level, ignoring the blurring effects of volume conductor, whereas the second class of information was more or less unavailable.
The lack of profound feedback on motor unit behaviour also limited the efficiency of stimulation fine-tuning and adaptation to individual person, as well as objective comparison of different stimulation protocols. The proposed project is, therefore, expected to have a profound effect also on the optimization of various stimulation devices and protocols and on promotion of non-invasive motor excitability investigation techniques in general. By providing the objective and highly detailed measures of CMAP properties, the project will also likely contribute to strengthening the interactions between technological and neurophysiological innovations.
On a long term, new neurophysiological findings, enabled by the proposed new methodology will boost the incorporation of new knowledge into available technical solutions as well as into neurological, kinesiological and rehabilitation procedures. All these positive effects will be additionally supported by the proposed strict control of quality of extracted information from CMAP.
Moreover, the project will clarify, on the level of individual motor neurons, the applicability and the potential of the proposed new methodology in the fields of a) cortical facilitations and inhibitions by transcranial magnetic stimulation (TMS), b) M wave analysis and its use in studies of post-activation potentiation in skeletal muscles and c) in studies of H reflex modulations. All three aforementioned analyses are highly relevant in the fields of basic neurophysiology, neurology, rehabilitation and sport sciences. Therefore, the three proposed demonstrators have been carefully selected to maximize the scientific and socio-economic outreach of the proposed project. Noteworthy, the very same CMAP decomposition concepts can easily be extended to numerous other stimulation scenarios such as analysis of F waves, for example.
Finally yet importantly, solving aforementioned methodological limitations will have a huge impact on neurophysiological community, contributing considerably to the visibility and promotion of Slovenian research excellence.
Most important scientific results
Interim report
Most important socioeconomically and culturally relevant results
Interim report
