Despite often applied, EMG does not provide information on all relevant aspects of a skeletal muscle. Muscle structure, metabolic properties, mechanical aspects and habitual activity cannot be detected by EMG and vary considerably between subjects, within and between various muscles and between healthy and diseased muscles. All of these factors have impact on each other, the function and well-being of particular muscle depends on all these characteristics of the neuromuscular system. Therefore, in order to obtain a “complete” description of the neuromuscular mechanisms involved in neuromuscular disorders, it is essential to attain simultaneous information (multimodal) of these factors (e.g., electrical activity, interstitial biochemical milieu environment, muscle architecture/structure) from a representative spatial area of the muscle (spatiotemporal).
Combination of several applicable techniques (mcEMG, mcNIR, FUS, and microdialysis) will provide information of electrical activity, blood volume and flow, muscle structure and mechanical contraction pattern, and metabolic environment from a large part of the investigated muscle. In addition, variables reflecting autonomic regulation will be used such as heart rate variability (HRV), respiration, blood pressure and skin conductance level.
The simultaneous information attained from these techniques will enhance the understanding of how the neuromuscular system is affected in neuromuscular disorders. Although the different techniques that are to be applied already exist, they are at present not all optimal to be used on skeletal muscles (FUS) or to include the spatial heterogeneity of muscles (mcNIR) and no processing methods exist at this very moment to integrate these results into interpretable datasets.