The project work has been organized into the following six work packages (WP):
WP1: Automatic identification of motor unit properties from EMG recordings
In this WP we developed new methodology for a) automatic identification of large number of motor units (MUs) and their electrophysiological properties from high-density surface electromyographic (hdEMG) signals; b) robust assessment of multichannel motor unit action potentials (MUAPs) from hdEMG signals; c) for estimation of motor unit filters to be used in calibration phase of compound muscle action potential (CMAP) decomposition; d) for assessment of fatigue profiles of individual motor units.
WP2: Development of techniques for CMAP decomposition
In this WP we developed and preliminary validated the algorithms for a) interpretation of spatial and temporal dispersion of CMAP’s components; b) decomposition of CMAPs into contributions of slow- and fast-twitch motor units and individual motor units. Algorithms for identifying motor unit firing patterns in CMAPs have been published in open access journals (e.g. DOI: 10.1113/JP284043, DOI: 10.1109/TBME.2022.3224962 and DOI: 10.1109/TNSRE.2022.3217450).
WP3: Advanced analysis of TMS induced MEPs
In this WP we validated the motor evoked potential (MEP) decomposition in various transcranial magnetic stimulation (TMS) experimental protocols and assessed the scientific and socio-economic impact and potential of MEP decomposition in studies of cortical excitability modulation. For example, in the study DOI: 10.1113/JP284043, we detected 30.7 ± 9.9 motor units per MEP in the first dorsal interosseous muscle and 28.9 ± 17.1 motor units per MEP in the tibialis anterior muscle.
WP4: Advanced analysis of CMAPs in nerve and muscle stimulation
In this WP we tested the validity, applicability, consistency and repeatability of developed CMAP decomposition methodology in the field of nerve/muscle stimulations and analysed different experimental conditions: post-activation potentiation, fatigue and bedrest (physical inactivity) interactions on the CMAP outcomes. For example, in the study DOI: 10.1109/TBME.2022.3224962, we detected the firings of 28.4 ± 14.3 motor units per maximal M wave elicited in the soleus muscle.
WP5: Advanced analysis of H reflexes
In this WP we tested the applicability, consistency and repeatability of developed decomposition methodology on electrically elicited H reflexes and analysed the accommodation patterns of different motor unit types in H reflex modulation. For example, in the study DOI: 10.1109/TNSRE.2022.3217450, we detected 14.1 ± 12.1, 18.2 ± 12.1 and 20.8 ± 8 motor units per H reflex in soleus muscle at rest and in 10% and 20% muscle activation, respectively. Individual motor unit firing latencies were 35.9 ± 3.3, 35.1 ± 3.0 and 34.6 ± 3.3 ms, respectively.
WP6: Dissemination of project’s results
The objectives of this WP were the management of the project, management of internal Intellectual Property Rights (IPR), management of dissemination activities and scientific and socio-economic exploitation of the results. We have patented the procedure and device for the decomposition of compound muscle action potentials. We obtained the Slovenian patent (No. 25939) on 30th of June 2021, and we also filed an application for the international protection (PCT WO 2021/126093 A1).
