Marco Gazzoni

Polytechnic University of Turin | polito · DET - Department of Electronics and Telecommunications

Tongue motor function is crucial in a wide range of basic activities and its impairment affects quality of life. The electrophysiological assessment of the tongue relies primarily on needle electromyography, which is limited by its invasiveness and inability to capture the concurrent activity of the different tongue muscles. This work aimed at deve...

After a stroke, antagonist muscle activation during agonist command impedes movement. This study compared measurements of antagonist muscle activation using surface bipolar EMG in the gastrocnemius medialis (GM) and high-density (HD) EMG in the GM and soleus (SO) during isometric submaximal and maximal dorsiflexion efforts, with knee flexed and ext...

The CNS may produce the same endpoint trajectory or torque profile with different muscle activation patterns. What differentiates these patterns is the presence of co-contraction, which does not contribute to effective torque generation but allows to modulate joints' mechanical stiffness. While it has been suggested that the generation of force and...

The clinical effects of a serious game with electromyography feedback (EMGs_SG) and physical therapy (PT) was investigated prospectively in children with unilateral spastic cerebral palsy (USCP). An additional aim was to better understand the influence of muscle shortening on function. Thirty children with USCP (age 7.6 ± 2.1 years) received four w...

The degeneration of lower motoneurons has often been reported in stroke survivors, with possible collateral reinnervation from the surviving motoneurons to the denervated muscle fibers. Under this assumption, a stroke would be expected to increase the size of motor units in paretic muscles. We indirectly address this issue with electrical stimulati...

Biofeedback based on electromyograms (EMGs) has been recently proposed to reduce exaggerated postural activity. Whether the effect of EMG biofeedback on the targeted muscles generalizes to – or is compensated by – other muscles is still an open question we address here. Fourteen young individuals were tested in three 60 s standing trials, without a...

Objective: Of recent interest is the use of EMG biofeedback to make subjects aware of their stabilizers' activation associated with scapular retraction during exercise, addressing challenges related to EMG detection. Whether there is an optimal bipolar positioning discriminating the stabilizers' activation with retraction from neutral scapular pos...

The CNS may produce the same endpoint trajectory or torque profile with different muscle activation patterns. What differentiates these patterns is the presence of co-contraction, which does not contribute to joint torque generation but allows to modulate mechanical impedance. Whether co-contraction is controlled through the same synaptic input to...

Different mechanisms of force transmission have been developed for the movement of wheelchairs, from the standard pushrim propulsion to the handbike. Contributing to this repertoire, we recently developed a system of propulsion based on a pulley-cable mechanism, the Handwheelchair.Q. In contrast to other propulsion systems, the Handwheelchair.Q req...

Corticokinematic coherence (CKC) is computed between limb kinematics and cortical activity (e.g. MEG, EEG), and it can be used to detect, quantify and localize the cortical processing of proprioceptive afference arising from the body. EEG-based studies on CKC have been limited to lab environments due to bulky, non-portable instrumentations. We rece...

Background and objectives Professional pianists tend to develop playing-related musculoskeletal disorders mostly in the forearm. These injuries are often due to overuse, suggesting the existence of a common forearm region where muscles are often excited during piano playing across subjects. Here we use a grid of electrodes to test this hypothesis,...

Sensorimotor integration is the process through which the human brain plans the motor program execution according to external sources. Within this context, corticomuscular and corticokinematic coherence analyses are common methods to investigate the mechanism underlying the central control of muscle activation. This requires the synchronous acquisi...

Work-related musculoskeletal disorders, reported at shoulder and low back regions, rank among the most serious health problems in industry. Owing to their ability in providing support to the shoulder and back regions during sustained and repetitive tasks, passive exoskeletons are expected to prevent work-related disorders. In this work, experimenta...

Neuromuscular electrical stimulation finds application in several fields, from basic neurophysiology, to motor rehabilitation and cardiovascular conditioning. Despite the progressively increasing interest in this technique, its State-of-the-Art technology is mainly based on monolithic, mostly wired devices, leading to two main issues. First, these...

Exoskeleton effectiveness in reducing muscle efforts has been usually assessed from surface electromyograms (EMGs) collected locally. It has been demonstrated, however, that muscle activity, redistribute within the low back muscles during static and dynamic contractions, suggesting the need of detecting surface EMGs from a large muscle region to re...

Muscle activity monitoring in dynamic conditions is a crucial need in different scenarios, ranging from sport to rehabilitation science and applied physiology. The acquisition of surface electromyographic (sEMG) signals by means of grids of electrodes (High-Density sEMG, HD-sEMG) allows to obtain relevant information on muscle function and recruitm...

This study aimed at determining the effect of a passive exoskeleton on local perceived discomfort, perceived effort and low back muscles’ activity. Thirteen volunteers performed two simulated working tasks with and without the exoskeleton. In the static task, the exoskeleton decreased the lumbar perceived discomfort, the perceived effort and the le...

Background: Fatigue in Parkinson's Disease (PD) compromises patients' physical activity and poses questions on how to plan correct rehabilitation training. In addition, the relationship between subjective perceived fatigue and fatigue in motor performance is not yet entirely understood. As a consequence, a conclusive interpretation of muscular mec...

Augmented reality is an emerging technology allowing to add computer-generated perceptual information superimposed to a real-world object. Biofeedback based on electromyography converts the muscle activation levels into visual or auditory information. This information can be used to facilitate or inhibit muscle contraction and is considered a suita...

The swallowing process involves the coordinated activation of several muscles to ensure the transfer of nutrients from the mouth to the stomach. A proper segmentation of swallowing into its constituent phases is relevant to obtain a quantitative biomechanical and electrophysiological description of this sensorimotor task. The aim of the study was t...

In this study we used the bipolar surface electromyography to investigate whether a passive exoskeleton reduces the degree of activity of shoulder muscles. Twelve young healthy volunteers participated in the study. Subjects were asked to hold four different static postures: (P1) shoulder abducted at 90°, elbow flexed at 90°, elbow pronated at 90°;...

Magneto-Inertial Measurement Units (MIMUs) are a valid alternative tool to optical stereophotogrammetry in human motion analysis. The orientation of a MIMU may be estimated by using sensor fusion algorithms. Such algorithms require input parameters that are usually set using a trial-and-error (or grid-search) approach to find the optimal values. Ho...

Magneto-Inertial Measurement Units (MIMUs) are a valid alternative tool to optical stereophotogrammetry in human motion analysis. The orientation of a MIMU may be estimated by using sensor fusion algorithms. Such algorithms require input parameters that are usually set using a trial-and-error (or grid-search) approach to find the optimal values. Ho...

PurposeDifferent motor units (MUs) in the biceps brachii (BB) muscle have been shown to be preferentially recruited during either elbow flexion or supination. Whether these different units reside within different regions is an open issue. In this study, we tested wheter MUs recruited during submaximal isometric tasks of elbow flexion and supination...

The transcutaneous stimulation of lower limb muscles during indoor rowing (FES Rowing) has led to a new sport and recreation and significantly increased health benefits in paraplegia. Stimulation is often delivered to quadriceps and hamstrings; this muscle selection seems based on intuition and not biomechanics and is likely suboptimal. Here, we sa...

Magneto-Inertial technology is an established alternative to optical motion capture for studying human movement. However, accuracy of its orientation estimation is still an open issue. In this study, we performed a concurrent validation of four common sensor fusion algorithms at three different speeds. A motion-specific fine-tuning of the filters p...

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Magneto-Inertial technology is a well-established alternative to optical motion capture for human motion analysis applications since it allows prolonged monitoring in free-living conditions. Magneto and Inertial Measurement Units (MIMUs) integrate a triaxial accelerometer, a triaxial gyroscope and a triaxial magnetometer in a single and lightweight...

The use of electrical stimulation to elicit single twitches and tetanic contractions of skeletal muscles has increased markedly in the last years, with applications ranging from basic physiology to clinical settings. Addressing all possible needs required by different applications with an electrical stimulator is challenging as it requires the devi...

The use of multiple surface EMG electrodes (High-Density surface EMG - HD-sEMG) allows the extraction of anatomical and physiological information either at the muscle or at the motor unit level with applications in several fields ranging from clinical neurophysiology to the control of prosthetic devices. These applications need to acquire monopolar...

In recent years, the variety of textile electrodes developed for electrophysiological signal detection has increased rapidly. Among the applications that could benefit from this advancement, those based on surface electromyography (sEMG) are particularly relevant in rehabilitation, training and muscle function assessment. In this work, we validate...

Objective: The use of linear or bi-dimensional electrode arrays for surface EMG detection (HD-sEMG) is gaining attention as it increases the amount and reliability of information extracted from surface EMG. However, the complexity of the setup and the encumbrance of HD-sEMG hardware currently limits its use in dynamic conditions. The aim of this wo...

Multi-channel sEMG techniques open new perspectives in the non-invasive assessment of neuromuscular system but currently, can be applied only during isometric or dynamic tasks because of the encumbrance of existing sEMG acquisition systems and their sensitivity to movement artefacts. The aim of this work is to describe a new, wireless, wearable, an...

People of industrialized countries are living longer and consequently the incidence of disability coming from medical conditions such as stroke is increasing. The hand rehabilitation process following a stroke accident requires very intense rehabilitation sessions. It is crucial to improve the outcomes of hand physical therapy by providing patients...

In this manuscript we describe the development and testing of a bipolar electrode for the simultaneous acquisition of ultrasound (US) images and surface electromyograms (EMGs) from the same muscle region. The developed electrode (bEMG-US) consists of two circular sensing regions (20 mm diameter) with fixed inter-electrode distance (3.5 cm, center-t...

Functional electrical stimulation of lower limb muscles during rowing provides a means for the cardiovascular conditioning in paraplegia. The possibility of shaping stimulation profiles according to changes in knee angle, so far conceived as changes in seat position, may help circumventing open issues associated with muscle fatigue and movement coo...

Inferences on the active contribution of plantar flexors to the stabilisation of human standing posture have been drawn from surface electromyograms (EMGs). Surface EMGs were however often detected unilaterally, presuming the myoelectric activity from muscles in a single leg reflects the pattern of muscle activation in both legs. In this study we q...

Objective: Humans usually tend to control more finely muscle force production in dominant than non-dominant upper limbs. It is well established that motor unit recruitment is a key mechanism by which muscle force is controlled, and we hypothesized that a relatively smaller number of motor units may be recruited in muscles of dominant than non-domi...

Introduction/Background Augmented Reality (AR) has been proved successful in several applications from surgical training to balance rehabilitation. This work aims to develop an AR system for real-time visualization of an index of muscle activity superimposed to the investigated muscle. Material and method The system includes: (1) a video camera, (...

Introduction/Background It has been inferred that stroke-induced alterations of the lower motor neurons and their muscle fibres may contribute to muscle weakness and thus to motor impairment. Although previous accounts have investigated the mechanisms underpinning muscle weakness from muscle fiber conduction velocity estimates, reports about how th...

INTRODUCTION Biofeedback based on electromyograms (EMGs) is a promising technique to suppress the excessive muscle activity during standing. Previous evidence for example showed that healthy, young subjects activate their plantar flexors to a lesser extent with than without EMG-audio feedback during standing [1]. However, the effect of EMG biofeedb...

Robotic technologies are progressively gaining considerable importance in motor rehabilitation. In this context, the development of non-invasive man-machine interfaces has a significant role. Among other physiological signals, surface EMG is of paramount importance. However, the detection of surface EMG signals in rehabilitation is currently based...

This work investigates the effect of different seats on violin and viola players sitting postures using High-Density-surface-Electromyography techniques (HDsEMG), biomechanical and comfort indices. Five types of chairs were assessed on 18 violin and three viola players by comparing: (a) pelvic tilt and kyphosis and lordosis angles, (b) subjective c...

Proper muscle activity quantification is highly relevant to monitor and treat spastic cocontraction. As activity may distribute unevenly within muscle volumes, particularly for pennate calf muscles, surface electromyograms (EMGs) detected by traditional bipolar montage may provide biased estimations of muscle activity. We compared cocontraction est...

During standing, age-related differences in the activation of ankle muscles have been reported from surface electromyograms (EMGs) sampled locally. Given though activity seems to distribute unevenly within ankle muscles, the local sampling of surface EMGs may provide a biased view on how often and how much elderly and young individuals activate the...

On a broad view, fatigue is used to indicate a somewhat degree of weariness. On the muscular level, fatigue posits the reduced capacity of muscle fibres to produce force, even in the presence of motor neuron excitation via either spinal mechanisms or electric pulses applied externally. Prior to decreased force, when sustaining physically demanding...

This chapter focuses on the most common form of feedback in physical rehabilitation: surface electromyograph (sEMG) biofeedback. It provides an overview of technical considerations and guidelines for the use of sEMG biofeedback and reviews some of its most common clinical applications. The principle of sEMG biofeedback is to provide the subject wit...

Prevention of musculoskeletal disorders is one of the main goals in ergonomics. The development of methods to quantify muscle force, fatigue, and muscle involvement in a work task is important for this purpose surface electromyography (sEMG) and kinematic measurements are the main tools for the quantitative evaluation of risks related to work activ...

One of the most important muscular groups which contribute to maintain standing balance is triceps surae. However, it is unclear whether the postural controllers of triceps surae, medial gastrocnemius (MG) and soleus (SOL), have different temporal patterns of activation during upright stance. This paper aimed at evaluating whether the global tempor...

In the last years, printing techniques have been developed for the realization of electronic circuits using functional inks. In this field inkjet printing technology has a number of attractive features and received a lot of interest with the development of specifically designed functional inks, including conductive inks based on silver nanoparticle...

Recent advances in high density surface electromyogram (EMG) decomposition have made it a feasible task to discriminate single motor unit activity from surface EMG interference patterns, thus providing a noninvasive approach for examination of motor unit control properties. In the current study we applied high density surface EMG recording and deco...

The study of hand and finger movement is an important topic with applications in prosthetics, rehabilitation, and ergonomics. Surface electromyography (sEMG) is the gold standard for the analysis of muscle activation. Previous studies investigated the optimal electrode number and positioning on the forearm to obtain information representative of mu...

Introduction: We investigated the motor unit (MU) firing pattern in type 2 diabetes mellitus (T2DM) patients by means of multichannel surface electromyography (SEMG). Methods: Eight T2DM patients and 8 age-matched, healthy men performed a ramp-up contraction to 20% of maximal voluntary contraction (MVC). They also performed a sustained contracti...

The aim of this study was to investigate the position of the innervation zone (IZ) of the vastus medialis (VM) and its effect on the electromyographic (EMG) amplitude and mean frequency estimates. Eighteen healthy subjects performed maximal isometric knee extensions at three knee angles. Surface EMG signals were collected by using a 16 × 8 electrod...

The electromyogram (EMG) is a compound signal comprising the electrical activity of the motor units (MU) activated asynchronously during voluntary muscle contractions. This chapter provides a basic overview of the technologies for the detection and conditioning of surface EMG (sEMG) signals. The first section focuses on electrode technology and the...

Aim. It is currently unknown whether preferential activation of the distal portion of the vastus medialis can be obtained by performing isometric knee extension exercises at selected knee angles and force levels. The aim of this study was to assess whether preferential activation of muscle sub-portions within the vastus medialis occurs at different...

The electromyogram is a compound signal comprising the electrical activity of the motor units activated asynchronously during voluntary muscle contractions. The temporal and spatial evolution of EMG can be sampled by surface electrodes. The basic principles and concepts about sEMG signal conditioning, spatial filtering, and spatial sampling are int...

The aim of this work is to show how changes in surface electromyographic activity (sEMG) during a repetitive, non-constant force contraction can be detected and interpreted on the basis of the amplitude distribution provided by high-density sEMG techniques. Twelve healthy male subjects performed isometric shoulder elevations, repeating five times a...

Space permanence simulations such as prolonged bed-rest can mimic some of the physiological modifications in the human body and provide study conditions that are more accessible than during space flight. A short term bed-rest experiment was organized to simulate the effects of weightlessness for studying the adaptation to this condition. Eight heal...

The prevention of work-related musculoskeletal disorders is one of the main goals in ergonomics. Among others, surface electromyography (sEMG) is an important tool for the evaluation of risks related to work activity. Three main issues have been approached in ergonomics via sEMG: 1) the analysis of muscle activation, 2) the analysis of exerted forc...

Fibromyalgia (FM) is characterised by diffuse musculoskeletal pain and stiffness at multiple sites, tender points in characteristic locations, and the frequent presence of symptoms such as fatigue. The aim of this study was to assess whether the myoelectrical manifestations of fatigue in patients affected by FM are central or peripheral in origin....

Traumas of the innervation zone (IZ) of the external anal sphincter (EAS), e.g. during delivery, can promote the development of faecal incontinence. Recently developed probes allow high-resolution detection of EMG signals from the EAS. The analysis of pelvic floor muscles by surface EMG (in particular, the estimation of the location of the IZ) has...

We systematically tested the capability of the Convolution Kernel Compensation (CKC) method to identify motor unit (MU) discharge patterns from the simulated and experimental surface electromyogram (sEMG) during low-force contractions. sEMG was detected with a grid of 13 x 5 electrodes. In simulated signals with 20 dB signal-to-noise ratio, 11+/-3...

We investigated the changes in muscle fiber conduction velocity, recruitment and derecruitment thresholds, and discharge rate of low-threshold motor units during a series of ramp contractions. The aim was to compare the adjustments in motor unit activity relative to the duration that each motor unit was active during the task. Multichannel surface...

Two physiological factors are assumed in this paper to mainly determine the myoelectric manifestations of fatigue: (1) the decrease of the conduction velocity (CV) of motor unit action potentials (MUAP) (peripheral fatigue), and (2) the increase of MU synchronization by the central nervous system (central fatigue). To describe separately the periph...

This study investigated the relative proportion of motor-unit action potentials that are uniquely represented in the simulated and experimental surface electromyogram (EMG). Two hundred motor units were simulated in a cylindrical anatomical system. Action potentials for each motor unit were generated with a model and then compared with those of oth...

Carpal Tunnel syndrome (CTS) is one of the most common compartmental syndromes and nerve conduction studies are widely considered as the standard to diagnose the pathology. The purpose of this pilot study was to investigate whether multichannel surface electromyography can detect muscle alterations in patients diagnosed with severe CTS. Surface EMG...

The aim of this study was to determine whether the rate of change of surface EMG variables during a constant force isometric fatiguing contraction (80% MVC, 30 s of duration) of vastus medialis obliquus (VMO) and vastus lateralis (VL) muscles is able to distinguish between nine sprinters and nine long distance runners. Signals were recorded with li...