Body Segments Research Articles

Muscular remodeling and anteroposterior patterning during tapeworm segmentation.

Tapeworms are parasitic flatworms that independently evolved a segmented body plan, historically confounding comparisons with other animals. Anteroposterior (AP) patterning in free-living flatworms and in tapeworm larvae is associated with canonical Wnt signaling and positional control genes (PCGs) are expressed by their musculature in regionalized domains along the AP axis. Here, we extend investigations of PCG expression to the adult of the mouse bile-duct tapeworm Hymenolepis microstoma, focusing on the growth zone of the neck region and the initial establishment of segmental patterning. We show that the adult musculature includes new, segmental elements that first appear in the neck and that the spatial patterns of Wnt factors are consistent with expression by muscle cells. Wnt factor expression is highly regionalized and becomes AP-polarized in segments, marking them with axes in agreement with the polarity of the main body axis, while the transition between the neck and strobila is specifically demarcated by the expression domain of a Wnt11 paralog. We suggest that segmentation could originate in the muscular system and participate in patterning the AP axis through regional and polarized expression of PCGs, akin to the gene regulatory networks employed by free-living flatworms and other animals.

Association of the oxidative balance score with obesity and body composition among young and middle-aged adults.

The oxidative balance score (OBS) is important for determining the cause of obesity and its complications. We aimed to evaluate the association between OBS and obesity and other segmental body composition parameters among young and middle-aged U.S. adults. 9,998 participants from the National Health and Nutrition Examination Survey 2011-2018 were included. Lean mass percentage (LM%) and FM% were evaluated by dual-energy x-ray absorptiometry. Obesity was defined as body FM% ≥25% in men and ≥ 35% in women. The OBS was scored by 5 pro-oxidant and 21 antioxidant factors. Associations of quartiles of OBS with obesity risk were estimated using multivariable logistic regression models. Multivariable linear regression was conducted to estimate the association between OBS and segmental body composition measures including the arm LM%, leg LM%, torso LM%, whole LM%, arm FM%, leg FM%, torso FM% and total FM%. Compared to participants in the lowest quartile of OBS, those in the highest quartile of OBS were associated with a lower risk of BMI-defined obesity BMI-defined obesity [0.43 (0.36, 0.50)] and FM%-related obesity [0.43 (0.35, 0.52)]. Additionally, OBS was negatively associated with FM% of the limb and torso but positively associated with the percentage of lean mass (LM%) of the limb and trunk. OBS was negatively associated with the risk of obesity and segmental FM%, but was positively associated with segmental LM% among US adults, indicating that adhering to an anti-oxidative diet and lifestyle management may be beneficial for preventing segmental obesity.

Development of equation of motion deciphering locomotion including omega turns of Caenorhabditis elegans.

Locomotion is a fundamental behavior of Caenorhabditis elegans (C. elegans). Previous works on kinetic simulations of animals helped researchers understand the physical mechanisms of locomotion and the muscle-controlling principles of neuronal circuits as an actuator part. It has yet to be understood how C. elegans utilizes the frictional forces caused by the tension of its muscles to perform sequenced locomotive behaviors. Here, we present a two-dimensional rigid body chain model for the locomotion of C. elegans by developing Newtonian equations of motion for each body segment of C. elegans. Having accounted for friction-coefficients of the surrounding environment, elastic constants of C. elegans, and its kymogram from experiments, our kinetic model (ElegansBot) reproduced various locomotion of C. elegans such as, but not limited to, forward-backward-(omega turn)-forward locomotion constituting escaping behavior and delta-turn navigation. Additionally, ElegansBot precisely quantified the forces acting on each body segment of C. elegans to allow investigation of the force distribution. This model will facilitate our understanding of the detailed mechanism of various locomotive behaviors at any given friction-coefficients of the surrounding environment. Furthermore, as the model ensures the performance of realistic behavior, it can be used to research actuator-controller interaction between muscles and neuronal circuits.

Development of equation of motion deciphering locomotion including omega turns of Caenorhabditis elegans

Locomotion is a fundamental behavior of Caenorhabditis elegans (C. elegans). Previous works on kinetic simulations of animals helped researchers understand the physical mechanisms of locomotion and the muscle-controlling principles of neuronal circuits as an actuator part. It has yet to be understood how C. elegans utilizes the frictional forces caused by the tension of its muscles to perform sequenced locomotive behaviors. Here, we present a two-dimensional rigid body chain model for the locomotion of C. elegans by developing Newtonian equations of motion for each body segment of C. elegans. Having accounted for friction-coefficients of the surrounding environment, elastic constants of C. elegans, and its kymogram from experiments, our kinetic model (ElegansBot) reproduced various locomotion of C. elegans such as, but not limited to, forward-backward-(omega turn)-forward locomotion constituting escaping behavior and delta-turn navigation. Additionally, ElegansBot precisely quantified the forces acting on each body segment of C. elegans to allow investigation of the force distribution. This model will facilitate our understanding of the detailed mechanism of various locomotive behaviors at any given friction-coefficients of the surrounding environment. Furthermore, as the model ensures the performance of realistic behavior, it can be used to research actuator-controller interaction between muscles and neuronal circuits.

Exoskeletons for Elderly Activity of Daily Living Assistance: A Review of Upper Limb Exoskeletons and Assessments

Population ageing is a major global issue. The elderly population aged 65 and above made up approximately 9% of the world's population in 2019, with projections indicating this will rise to 16%, or 1.5 billion individuals, by 2050. The elderly experience a natural decline in strength, endurance, agility, and flexibility. Exoskeletons have the potential to assist the elderly in daily tasks, improve mobility and balance, and provide additional strength, endurance, and capability to maintain accurate limb movement. Their application leads to a more independent and autonomous life, fostering healthy ageing and ageing in place. However, their development requires thorough considerations of functionality and user experience criteria, such as addressing the alignment with human joints, social acceptance, and motivation for exoskeleton usage. This review presents an overview of upper-limb exoskeletons designed to assist the elderly in activities of daily living, focusing on exoskeleton types and assessments. Eighteen upper limb exoskeletons were identified from the literature and categorised based on supported body segment and structure. Most of the exoskeletons are either in the embodiment design or prototyping stages and their evaluations were predominantly performed in the laboratory or simulated environment. Elderly participation in exoskeleton assessment is currently limited. There is a lack of standardized exoskeleton assessments essential for certifications, commercialization, and universal benchmarks in diverse studies. These standards would ensure consistent, repeatable, reliable, validated, and comparable findings

Helical Actuator–Driven Inchworm Robot Design and Prototype

Abstract Bio-inspired robots provide solutions in many applications. Robots that can traverse and transport materials through confined areas are useful in disaster response, mining, mapping, and tunneling. The proposed robot is an inchworm-inspired robot that contracts and expands its body segments to move. It has spiky feet that are angled to only allow each foot to slide forward. It has a small frontal area compared to its length, and this allows it to travel through tight gaps or tunnels. Each segment uses two helical actuators as prismatic linkages to drive both forward movement and turning movement. These helical actuators transform the rotation of stepper motors into linear motion. Many linkage configurations were considered in designing this robot, and one without continuous singularities was selected. The robot stride consists of an extension phase and a contraction phase. In each phase, one foot is stationary, and one foot is moving. When each of the feet is in motion, the ground reaction force is assumed to be zero. The motion planning of the robot is designed so that the velocity and acceleration of each of the robot's rigid bodies are zero at the beginning and end of each movement phase. A 3D-printed prototype of the robot has been manufactured, and initial testing has shown that the foot spike design successfully allows the inchworm to shuffle forward. Testing the turning capabilities of this robot is ongoing.

Markerless motion capture provides repeatable gait outcomes in patients with knee osteoarthritis

Motion analysis has seen minimal adoption for orthopaedic clinical assessments. Markerless motion capture solutions, namely Theia3D, address limitations of previous methods and provide gait outcomes that are robust to clothing choice and repeatable in healthy adults. Repeatability in orthopaedic populations has not been investigated and is important for clinical utility and adoption. The purpose of this study was to evaluate the repeatability of Theia3D for gait analysis in a knee osteoarthritis population. Ten orthopaedic patients with knee osteoarthritis underwent gait analysis on three visits, with an average of 8 days between. Participants were recorded during one-minute overground walking trials at self-selected typical and fast speeds by 8 synchronized video cameras. Video data were processed using Theia3D. Intraclass correlations were used to examine the repeatability of temporal distance metrics as well as segment lengths of the underlying kinematic model. Inter-trial and inter-session variability of lower extremity joint angles were estimated for each point of the gait cycle. Intraclass correlations were greater than 0.98 for all temporal distance metrics for both speeds. Lower body segment lengths had intraclass correlations above 0.90. Participant average joint angle waveforms displayed consistent patterns between visits. The average inter-trial and inter-session variability in joint angles across speeds were 1.17 and 1.45 degrees, respectively. The variability in joint angles between visits was less than typically reported for marker-based methods. Gait outcomes measured with Theia3D were highly repeatable in patients with knee osteoarthritis providing further validation for its use in clinical assessment and longitudinal studies.

Deep multimodal spatio-temporal Harris Hawk Optimized Pose Recognition framework for self-learning fitness exercises

Human pose recognition from videotapes has become an emerging research topic for tracking human movements. The objective of this work is to develop a deep multimodal Spatio-Temporal Harris Hawk Optimized Pose Recognition (STHHO-PR) framework for self-learning fitness exercises. The presented STHHO-PR framework uses audio modality and visual modality to classify the different poses. In audio modality, the VGG-16 network paradigm is used to extract the audio traits for fitness pose recognition. In visual modality, Harris Hawks Optimization (HHO) along with the Minimum Cross Entropy (MCE) method is employed to find out the optimum threshold values for body parts segmentation. These segmented body parts highlight the human joint points that are connected through the skeletonization process to extract the skeletal information. The extracted spatio-temporal features from audio modality and visual modality are optimally fused and used in the classification process. Weighted Majority Voting Ensemble (WMVE) classifier is adopted to build the classification model. This work is experimented with yoga videos acquired from publicly available datasets. The results show that the presented STHHO-PR framework outperforms other state-of-art procedures in terms of prediction accuracy.

Inter- and intra-athlete technique variability of conventional new ball swing bowling in elite and pre-elite Australian male fast bowlers

ABSTRACT This study aimed to investigate inter- and intra-athlete technique variability in pre-elite and elite Australian fast bowlers delivering new ball conventional swing bowling. Ball grip angle and pelvis, torso, shoulder, elbow, wrist, upper arm, forearm, and hand kinematics were investigated at the point of ball release for inswing and outswing deliveries. Descriptive evaluations of group and individual data and k-means cluster analyses were used to assess inter- and intra-bowler technique variability. Inter-athlete technique and ball grip variability were identified, demonstrating that skilled bowlers use individualised strategies to generate swing. Functional movement variability was demonstrated by intra-athlete variability in successful swing bowling trials. Bowlers demonstrated stable technique parameters in large proximal body segments of the pelvis and torso, providing a level of repeatability to their bowling action. Greater variation was observed in bowling arm kinematics, allowing athletes to manipulate the finger and ball position to achieve the desired seam orientation at the point of ball release. This study demonstrates that skilled bowlers use individualised techniques and grips to generate swing and employ technique variations in successive deliveries. Coaches should employ individualised training strategies and use constraints-led approaches in training environments to encourage bowlers to seek adaptive movement solutions to generate swing.

Association between Urinary Sodium Excretion and Body Fat in School-Aged Children: Insights from the ARIA Study.

Childhood obesity has been associated with increased sodium intake. Nonetheless, evidence linking sodium intake to Body Mass Index (BMI) and Body Fat Mass Percentage (%BF) remains limited, especially in the pediatric age group. Therefore, this study aims to investigate whether there is an association between 24 h urinary sodium excretion with BMI and %BF in a sample group of children from the ARIA study. This cross-sectional analysis included 303 children aged 7 to 12 from across 20 public schools in Porto, Portugal. Weight and %BF were assessed using the Tanita™ BC-418 Segmental Body Analyzer. Children's Total Energy Intake (TEI) was estimated through a single 24 h Recall Questionnaire, and urinary sodium and potassium excretion was estimated by a 24 h urine collection. The association of %BF and BMI with 24 h sodium excretion was estimated by a binary logistic regression adjusted for sex, age, physical activity, total energy intake, parental education, and 24 h urinary excreted potassium. There was a significant positive association between higher levels of urinary sodium excretion and higher %BF values, even after adjusting for confounders. However, the same was not observed for BMI. Our findings suggest that higher sodium intake is associated with higher values of %BF among children, regardless of TEI and potassium intake.

Cross-sectional study on the impact of adverse childhood experiences on coronary flow reserve in male physicians with and without occupational burnout

ObjectivePhysicians face documented challenges to their mental and physical well-being, particularly in the forms of occupational burnout and cardiovascular disease. This study examined the previously under-researched intersection of early life stressors, prolonged occupational stress, and cardiovascular health in physicians. MethodsParticipants were 60 practicing male physicians, 30 with clinical burnout, defined by the Maslach Burnout Inventory, and 30 non-burnout controls. They completed the Adverse Childhood Experiences (ACE) Questionnaire asking about abuse, neglect and household dysfunctions before the age of 18, and the Perceived Stress Scale to rate thoughts and feelings about stress in the past month. Endothelium-independent (adenosine challenge) coronary flow reserve (CFR) and endothelium-dependent CFR (cold pressor test) were assessed by positron emission tomography-computed tomography. The segment stenosis score was determined by coronary computed tomography angiography. ResultsTwenty-six (43%) participants reported at least one ACE and five (8%) reported ≥4 ACEs. A higher ACEs sum score was associated with lower endothelium-independent CFR (r partial (rp) = −0.347, p = .01) and endothelium-dependent CFR (rp = −0.278, p = .04), adjusting for age, body mass index, perceived stress and segment stenosis score. In exploratory analyses, participants with ≥4 ACEs had lower endothelium-independent CFR (rp = −0.419, p = .001) and endothelium-dependent CFR (rp = −0.278, p = .04), than those with <4 ACEs. Endothelium-dependent CFR was higher in physicians with burnout than in controls (rp = 0.277, p = .04). No significant interaction emerged between burnout and ACEs for CFR. ConclusionThe findings suggest an independent association between ACEs and CFR in male physicians and emphasize the nuanced relationship between early life stressors, professional stress, and cardiovascular health.

Limb Volume Measurements: A Comparison of Circumferential Techniques and Optoelectronic Systems against Water Displacement.

Accurate measurements of limb volumes are important for clinical reasons. We aimed to assess the reliability and validity of two centimetric and two optoelectronic techniques for limb volume measurements against water volumetry, defined as the gold standard. Five different measurement methods were executed on the same day for each participant, namely water displacement, fixed-height (circumferences measured every 5 (10) cm for the upper (lower limb) centimetric technique, segmental centimetric technique (circumferences measured according to proportional height), optoelectronic plethysmography (OEP, based on a motion analysis system), and IGOODI Gate body scanner technology (which creates an accurate 3D avatar). A population of 22 (15 lower limbs, 11 upper limbs, 8 unilateral upper limb lymphoedema, and 6 unilateral lower limb lymphoedema) participants was selected. Compared to water displacement, the fixed-height centimetric method, the segmental centimetric method, the OEP, and the IGOODI technique resulted in mean errors of 1.2, 0.86, -16.0, and 0.71%, respectively. The corresponding slopes (and regression coefficients) of the linear regression lines were 1.0002 (0.98), 1.0047 (0.99), 0.874 (0.94) and 0.9966 (0.99). The centimetric methods and the IGOODI system are accurate in measuring limb volume with an error of <2%. It is important to evaluate new objective and reliable techniques to improve diagnostic and follow-up possibilities.

Soft skeletons transmit force with variable gearing.

A hydrostatic skeleton allows a soft body to transmit muscular force via internal pressure. A human's tongue, an octopus' arm and a nematode's body illustrate the pervasive presence of hydrostatic skeletons among animals, which has inspired the design of soft engineered actuators. However, there is a need for a theoretical basis for understanding how hydrostatic skeletons apply mechanical work. We therefore modeled the shape change and mechanics of natural and engineered hydrostatic skeletons to determine their mechanical advantage (MA) and displacement advantage (DA). These models apply to a variety of biological structures, but we explicitly consider the tube feet of a sea star and the body segments of an earthworm, and contrast them with a hydraulic press and a McKibben actuator. A helical winding of stiff, elastic fibers around these soft actuators plays a critical role in their mechanics by maintaining a cylindrical shape, distributing forces throughout the structure and storing elastic energy. In contrast to a single-joint lever system, soft hydrostats exhibit variable gearing with changes in MA generated by deformation in the skeleton. We found that this gearing is affected by the transmission efficiency of mechanical work (MA×DA) or, equivalently, the ratio of output to input work. The transmission efficiency changes with the capacity to store elastic energy within helically wrapped fibers or associated musculature. This modeling offers a conceptual basis for understanding the relationship between the morphology of hydrostatic skeletons and their mechanical performance.

Body composition assessment by artificial intelligence can be a predictive tool for short-term postoperative complications in Hartmann’s reversals

BackgroundHartmann's reversal, a complex elective surgery, reverses and closes the colostomy in individuals who previously underwent a Hartmann's procedure due to colonic pathology like cancer or diverticulitis. It demands careful planning and patient optimisation to help reduce postoperative complications. Preoperative evaluation of body composition has been useful in identifying patients at high risk of short-term postoperative outcomes following colorectal cancer surgery. We sought to explore the use of our in-house derived Artificial Intelligence (AI) algorithm to measure body composition within patients undergoing Hartmann’s reversal procedure in the prediction of short-term postoperative complications.MethodsA retrospective study of all patients who underwent Hartmann's reversal within a single tertiary referral centre (Western) in Melbourne, Australia and who had a preoperative Computerised Tomography (CT) scan performed. Body composition was measured using our previously validated AI algorithm for body segmentation developed by the Department of Surgery, Western Precinct, University of Melbourne. Sarcopenia in our study was defined as a skeletal muscle index (SMI), calculated as Skeletal Muscle Area (SMA) /height2 < 38.5 cm2/m2 in women and < 52.4 cm2/m2 in men.ResultsBetween 2010 and 2020, 47 patients (mean age 63.1 ± 12.3 years; male, n = 28 (59.6%) underwent body composition analysis. Twenty-one patients (44.7%) were sarcopenic, and 12 (25.5%) had evidence of sarcopenic obesity. The most common postoperative complication was surgical site infection (SSI) (n = 8, 17%). Sarcopenia (n = 7, 87.5%, p = 0.02) and sarcopenic obesity (n = 5, 62.5%, p = 0.02) were significantly associated with SSIs. The risks of developing an SSI were 8.7 times greater when sarcopenia was present.ConclusionSarcopenia and sarcopenic obesity were related to postoperative complications following Hartmann’s reversal. Body composition measured by a validated AI algorithm may be a beneficial tool for predicting short-term surgical outcomes for these patients.

Room-scale Location Trace Tracking via Continuous Acoustic Waves

The increasing prevalence of smart devices spurs the development of emerging indoor localization technologies for supporting diverse personalized applications at home. Given marked drawbacks of popular chirp signal-based approaches, we aim at developing a novel device-free localization system via the continuous wave of the inaudible frequency. To achieve this goal, solutions are developed for fine-grained analyses, able to precisely locate moving human traces in the room-scale environment. In particular, a smart speaker is controlled to emit continuous waves at inaudible 20kHz , with a co-located microphone array to record their Doppler reflections for localization. We first develop solutions to remove potential noises and then propose a novel idea by slicing signals into a set of narrowband signals, each of which is likely to include at most one body segment’s reflection. Different from previous studies, which take original signals themselves as the baseband, our solutions employ the Doppler frequency of a narrowband signal to estimate the velocity first and apply it to get the accurate baseband frequency, which permits a precise phase measurement after I-Q (i.e., in-phase and quadrature) decomposition. A signal model is then developed, able to formulate the phase with body segment’s velocity, range, and angle. We next develop novel solutions to estimate the motion state in each narrowband signal, cluster the motion states for different body segments corresponding to the same person, and locate the moving traces while mitigating multi-path effects. Our system is implemented with commodity devices in room environments for performance evaluation. The experimental results exhibit that our system can conduct effective localization for up to three persons in a room, with the average errors of 7.49 cm for a single person, with 24.06 cm for two persons, with 51.15 cm for three persons.

Sagittal balance parameters measurement on cervical spine MR images based on superpixel segmentation.

Introduction: Magnetic Resonance Imaging (MRI) is essential in diagnosing cervical spondylosis, providing detailed visualization of osseous and soft tissue structures in the cervical spine. However, manual measurements hinder the assessment of cervical spine sagittal balance, leading to time-consuming and error-prone processes. This study presents the Pyramid DBSCAN Simple Linear Iterative Cluster (PDB-SLIC), an automated segmentation algorithm for vertebral bodies in T2-weighted MR images, aiming to streamline sagittal balance assessment for spinal surgeons. Method: PDB-SLIC combines the SLIC superpixel segmentation algorithm with DBSCAN clustering and underwent rigorous testing using an extensive dataset of T2-weighted mid-sagittal MR images from 4,258 patients across ten hospitals in China. The efficacy of PDB-SLIC was compared against other algorithms and networks in terms of superpixel segmentation quality and vertebral body segmentation accuracy. Validation included a comparative analysis of manual and automated measurements of cervical sagittal parameters and scrutiny of PDB-SLIC's measurement stability across diverse hospital settings and MR scanning machines. Result: PDB-SLIC outperforms other algorithms in vertebral body segmentation quality, with high accuracy, recall, and Jaccard index. Minimal error deviation was observed compared to manual measurements, with correlation coefficients exceeding 95%. PDB-SLIC demonstrated commendable performance in processing cervical spine T2-weighted MR images from various hospital settings, MRI machines, and patient demographics. Discussion: The PDB-SLIC algorithm emerges as an accurate, objective, and efficient tool for evaluating cervical spine sagittal balance, providing valuable assistance to spinal surgeons in preoperative assessment, surgical strategy formulation, and prognostic inference. Additionally, it facilitates comprehensive measurement of sagittal balance parameters across diverse patient cohorts, contributing to the establishment of normative standards for cervical spine MR imaging.

The Role of Upper Body Motions in Stationary Ball-Kicking Motion: A Systematic Review

AbstractA ball-kicking motion requires a coordinated sequencing of all body segments for maximum ball release speed. Evidence of the role of upper body rotations and motor coordination during a ball-kicking motion is inconsistent among existing evidence. This study aimed to systematically review the role of upper body rotations on all modes of ball kicking and performance metrics. A comprehensive search of seven electronic databases from the inception was conducted. Studies reporting on the relationships between upper body rotation, and ball-kicking performance were included. From 1486 potentially relevant studies, we analysed 27 studies involving 457 participants. These studies encompassed instep soccer kicks (n = 21), inside-of-the-foot soccer kicks (n = 1), rugby place kicks (n = 4) with a stationary ball, and a volley kick (n = 1). Methodological quality assessment was performed using Standard Quality Assessment Criteria. Our results provide moderate evidence that increasing thoracolumbar rotations along the longitudinal axis and the transverse plane can enhance ball-releasing velocity through a "whip-like effect" based on the kinetic link principle. However, to gain a comprehensive understanding, further research is needed to explore the effects of timing and the ranges of motion of all relevant upper and lower body segments on ball release velocity and its potential influence on ball release accuracy. The current coaching manuals do not emphasise the significance of upper body rotation, indicating a pressing requirement for revisions in training guidelines to enhance ball-kicking performance.

Arm muscle synergies enhance hand posture prediction in combination with forearm muscle synergies

Objective. We analyze and interpret arm and forearm muscle activity in relation with the kinematics of hand pre-shaping during reaching and grasping from the perspective of human synergistic motor control. Approach. Ten subjects performed six tasks involving reaching, grasping and object manipulation. We recorded electromyographic (EMG) signals from arm and forearm muscles with a mix of bipolar electrodes and high-density grids of electrodes. Motion capture was concurrently recorded to estimate hand kinematics. Muscle synergies were extracted separately for arm and forearm muscles, and postural synergies were extracted from hand joint angles. We assessed whether activation coefficients of postural synergies positively correlate with and can be regressed from activation coefficients of muscle synergies. Each type of synergies was clustered across subjects. Main results. We found consistency of the identified synergies across subjects, and we functionally evaluated synergy clusters computed across subjects to identify synergies representative of all subjects. We found a positive correlation between pairs of activation coefficients of muscle and postural synergies with important functional implications. We demonstrated a significant positive contribution in the combination between arm and forearm muscle synergies in estimating hand postural synergies with respect to estimation based on muscle synergies of only one body segment, either arm or forearm (p < 0.01). We found that dimensionality reduction of multi-muscle EMG root mean square (RMS) signals did not significantly affect hand posture estimation, as demonstrated by comparable results with regression of hand angles from EMG RMS signals. Significance. We demonstrated that hand posture prediction improves by combining activity of arm and forearm muscles and we evaluate, for the first time, correlation and regression between activation coefficients of arm muscle and hand postural synergies. Our findings can be beneficial for myoelectric control of hand prosthesis and upper-limb exoskeletons, and for biomarker evaluation during neurorehabilitation.

Neuro-Inspired Motion Control of a Soft Myriapod Robot

Centipedes exploit soft structures to move efficiently in complex environments. These abilities have promoted scientists to develop centipede-like robots with soft robot technologies. In this paper, a centipede-like robot constructed by multiple body segments connected in series is designed. Each body segment features a pair of antagonistic artificial muscles and four electro-adhesive feet, which plays the role of the basic motion unit of the centipede-like robot and can be regarded as a soft myriapod robot. To accomplish the desired movement tasks for the soft myriapod robot, this paper proposes a neuro-inspired hierarchical motion control scheme according to the functions of the centipede brain. In the proposed control scheme, a mushroom-body-inspired controller with an error-based learning mechanism is adopted for the soft actuator motion control, and a central-complex-inspired deep reinforcement learning algorithm is designed for the robot motion selection. At last, the effectiveness of the proposed motion control scheme is verified via both numerical studies and experiments.

Forearm bisection task suggests an alteration in Body Schema in patients with Motor Conversion Disorders (Functional Movement Disorders)

IntroductionMotor Conversion Disorders (also called Functional Movement Disorders, FMD) are a group of neuropsychiatric conditions characterized by neurological symptoms of altered voluntary motor function that cannot be explained by typical neurological diseases or other medical conditions. In the last decade, several hypotheses have been formulated with respect to their pathophysiology, and a major line of research, trying to integrate psychological, cognitive, and neurobiological factors, focused on the subjective experience that patients feel of their own bodies. However, no study has, so far, directly investigated their Body Schema (the implicit sensorimotor representation of one’s own body) and its plasticity.ObjectivesTo investigate the Body Schema in patients with FMD through a paradigm specifically designed to assess their perceived body metrics, through a spatial estimation of body parts length, and to compare their results with the ones obtain on a group of healthy control subjects (HC)Methods10 patients with FMD and 11 HC underwent the Forearm Bisection Task, aimed at assessing perceived body metrics, which consists in asking the subject, blindfolded, to repeatedly point at the perceived middle point of their dominant forearm with the index finger of their contralateral hand, and a psychometric assessment for anxiety, depression, alexithymia, and tendency to dissociation.ResultsFMD patients bisected their forearm more proximally (with an increased shift towards their elbow equal to 7.5%) with respect to HC; average bisection point was positively associated with anxiety levels in the whole sample, and with the tendency to dissociation in the FMD group.ConclusionsFMD patients seem to perceive their forearm as shorter than HC do, which might suggest an alteration of their Body Schema. The Body Schema can go through short- and long-term plastic changes in the life course, mainly related to the use of each body segment; we speculate that, despite FMD being a disorder of functional nature, characterized by variability and fluctuations in symptomatology, the lack of sense of agency over a body part might be interpreted by the nervous system as disuse and hence influence the Body Schema, as deficits of organic aetiology do.Disclosure of InterestNone Declared