Critical Issues and Imminent Challenges in the Use of sEMG in Return-To-Work Rehabilitation of Patients Affected by Neurological Disorders in the Epoch of Human–Robot Collaborative Technologies

Abstract

Patients affected by neurological pathologies with motor disorders when they are of working age have to cope with problems related to employability, difficulties in working, and premature work interruption. It has been demonstrated that suitable job accommodation plans play a beneficial role in the overall quality of life of pathological subjects. A well-designed return-to-work program should consider several recent innovations in the clinical and ergonomic fields. One of the instrument-based methods used to monitor the effectiveness of ergonomic interventions is surface electromyography (sEMG), a multi-channel, non-invasive, wireless, wearable tool, which allows in-depth analysis of motor coordination mechanisms. Although the scientific literature in this field is extensive, its use remains significantly underexploited and the state-of-the-art technology lags expectations. This is mainly attributable to technical and methodological (electrode-skin impedance, noise, electrode location, size, configuration and distance, presence of crosstalk signals, comfort issues, selection of appropriate sensor setup, sEMG amplitude normalization, definition of correct sEMG-related outcomes and normative data) and cultural limitations. The technical and methodological problems are being resolved or minimized also thanks to the possibility of using reference books and tutorials. Cultural limitations are identified in the traditional use of qualitative approaches at the expense of quantitative measurement-based monitoring methods to design and assess ergonomic interventions and train operators. To bridge the gap between the return-to-work rehabilitation and other disciplines, several teaching courses, accompanied by further electrodes and instrumentations development, should be designed at all Bachelor, Master and PhD of Science levels to enhance the best skills available among physiotherapists, occupational health and safety technicians and ergonomists.

Bipolar versus high-density surface electromyography for evaluating risk in fatiguing frequency-dependent lifting activities

“…Such a limitation can be mitigated by adopting wireless HDsEMG technology (limiting the amount of acquired channels to e.g. 64 channels) and/or including the use of sensorized garments (SOPHIA project) to simplify the application of HDsEMG (Ajoudani et al, 2020;Ranavolo et al, 2020b). A limitation of this study could be the use of both men and women as gender differences in the activation of the erector spinae may exist.…”

An ergonomic assessment tool for evaluating the effect of back exoskeletons on injury risk

“…EMG is a great tool for research but is difficult to use as the basis for accessible, scalable, practical ergonomic assessment, particularly for the back. To briefly summarize key challenges: (i) EMG requires considerable time and expertise to collect and process (Besomi et al, 2020), and as such this level of analysis is not accessible or affordable for most safety professionals; (ii) there are an abundance of back extensor muscles, many of which are not measurable with surface EMG, meaning EMG studies only capture a subset of back muscle behaviors; (iii) there is substantial inter-subject variability with respect to which back muscles individuals offload and in what proportion when exo assistance is provided (Lamers et al, 2020), meaning it is unclear which subset of muscles to measure or how to make equitable comparisons between different individuals or exos; (iv) EMG only captures changes in muscle activity, and fails to capture reductions in spinal ligament loading (e.g., during stooped bending); (v) the relationship between EMG and force is non-linear, and dependent on other factors like muscle length, contraction velocity, electrode placement, and body posture (Ranavolo et al, 2020;Trinler et al, 2018), which can confound exo vs. no exo comparisons if kinematics are not tracked or controlled (Koopman et al, 2020a;Lamers et al, 2020); (vi) there can be safety concerns with normalization procedures that require maximum contractions (Cholewicki et al, 2011); and (vii) there is within-and betweenparticipant variability when measuring EMG (e.g., due to motion artifacts, tissue conductivity) even without exos (Cholewicki et al, 2011), which can introduce reliability or interpretation issues, and these must be overcome with rigorous experimental design and data processing (Besomi et al, 2020).…”

Indexes for motor performance assessment in job integration/reintegration of people with neuromuscular disorders: A systematic review

“…Furthermore, novel ergonomic solutions, such as work task rehabilitation and workplace interventions, are being added to job accommodation plans ( 35 – 37 ). Indeed, the fourth industrial revolution has lately opened up new occupational scenarios in which crucial human–robot collaboration (HRC) technologies, such as collaborative robots and exoskeletons, aid workers in their workplaces ( 3 ).…”

“…When a worker affected by a neurological pathology with motor disorders is reintegrated at work, an exhaustive assessment of his/her residual motor function is of primary importance to design and/or optimally adapt his/her workplace. Therefore, biomechanical and physiological indexes are useful for monitoring motor and muscle performance and verifying the effectiveness of interventions for job integration/reintegration ( 3 ).…”

“…Furthermore, the efficiency of these ergonomic interventions should be verified and monitored throughout time ( 3 ). Kinematic, kinetic, and surface electromyography (sEMG) measurements are now widely used in research laboratories by movement scientists and could be used more and more in clinical practice by health operators, to define quantitatively the form and degree of motor dysfunction, assess the complicated interaction between the fundamental deficit and the adaptive and compensating mechanisms, categorize patients based on their specific neurological condition, and finally monitor pre–post-treatment ( 3 ).…”