Investigation of muscle activation during kinetic chain based exercises in individuals with and without forward head posture.

BACKGROUND: The Band Pull-Apart (BPA) exercise is used to strengthen the periscapular muscles. It was recently stated that the lower extremity and trunk movements should be included in the shoulder rehabilitation programs to optimize an effective energy transfer throughout the kinetic chain. OBJECTIVE: The aim of this study is to investigate the effects of kinetic chain based BPA exercise on the muscle activations of the sternocleidomasteideous (SCM) and the trapezius muscles in individuals with and without forward head posture (FHP). METHODS: Eighteen individuals with FHP and 18 individuals without FHP were included. Photographic measurements were made to identify individuals with FHP. The muscle activations of SCM, Upper Trapezius (UT), Middle Trapezius (MT), and Lower Trapezius (LT) were measured with surface EMG. BPA exercise was performed in the standing, unipedal standing, squat, unipedal squat, and Bulgarian split squat (BSS). RESULTS: There was no Group × Exercise interaction for the SCM, UT, MT, LT muscle activations, or for the UT/MT and UT/LT ratios (p> 0.05). While there was a difference in the activation of all muscles between individuals with and without FHP (p< 0.05), both ratios were similar (p> 0.05). There was a statistically significant difference between exercises for SCM, MT, and LT muscle activations (p< 0.000 for these muscles), UT/MT (p< 0.000) and UT/LT ratios (p= 0.004). SCM muscle activation in squat was lower than activation in standing (Mean Difference (MD) = 2.5% Maximal Voluntary Isometric Contractions (MVIC); p= 0.004) and in unipedal standing (MD = 2.1% MVIC; p= 0.002). MT muscle activation in squat was higher than activation in standing (MD = 9.7% MVIC), unipedal standing (MD = 7.8% MVIC), unipedal squat (MD = 6.9% MVIC) and BSS (MD = 9.4% MVIC; p< 0.000 for these positions). LT muscle activation in the squat was higher than activation in the standing (MD = 8.5% MVIC) and unipedal squat (MD = 8.1% MVIC; p< 0.004 for these positions). UT/MT ratio in the squat was lower than standing (MD = 0.3), unipedal standing (MD = 0.2) and BSS (MD = 0.3; p< 0.000 for these positions). UT/LT ratio in squat was lower than unipedal squat (MD = 0.5) and BSS (MD = 0.6; p= 0.002; for these positions). CONCLUSION: Performing the BPA exercise in the squat position is suggested in cases where lower SCM and UT muscle activation, lower UT/MT, and UT/LT ratios and higher MT and LT muscle activations are needed for individuals with and without FHP.

Relationship between Abnormal Spontaneous Brain Activity and Altered Neuromuscular Activation of Lumbar Paraspinal Muscles in Chronic Low Back Pain.

OBJECTIVE: To investigate the neural mechanism underlying functional reorganization and motor coordination strategies in patients with chronic low back pain (cLBP). DESIGN: A case-control study based on data collected during routine clinical practice. SETTING: This study was conducted at the the First Affiliated Hospital of Sun Yat-sen University. PARTICIPANTS: Fifteen patients with cLBP and fifteen healthy controls. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Whole brain blood oxygen level-dependent signals were measured using functional magnetic resonance imaging and amplitude of low-frequency fluctuation (ALFF) method to identify pain-induced changes in regional spontaneous brain activity. A novel approach based on the surface electromyography (EMG) system and fine-wire electrodes was used to record EMG signals in the deep multifidus, superficial multifidus, and erector spinae. RESULTS: In cLBP, compared with healthy groups, ALFF was higher in the medial prefrontal, primary somatosensory, primary motor, and inferior temporal cortices, whereas it was lower in the cerebellum and anterior cingulate and posterior cingulate cortices. Furthermore, the decrease in the average EMG activity of three lumbar muscles in the cLBP group was positively correlated with the ALFF values of the primary somatosensory cortex, motor cortex, precuneus, and middle temporal cortex but significantly negatively correlated with the ALFF values of the medial prefrontal and inferior temporal cortices. Interestingly, the correlation between the functional activity in the cerebellum and the EMG activity varied in the lumbar muscles. CONCLUSIONS: These findings suggest a functional association between changes in spontaneous brain activity and altered voluntary neuromuscular activation patterns of the lumbar paraspinal muscles, providing new insights into the mechanisms underlying pain chronicity as well as important implications for developing novel therapeutic targets of cLBP.

Advancing clinical understanding of surface electromyography biofeedback: bridging research, teaching, and commercial applications.

INTRODUCTION: Expanding the use of surface electromyography-biofeedback (EMG-BF) devices in different therapeutic settings highlights the gradually evolving role of visualizing muscle activity in the rehabilitation process. This review evaluates their concepts, uses, and trends, combining evidence-based research. AREAS COVERED: This review dissects the anatomy of EMG-BF systems, emphasizing their transformative integration with machine-learning (ML) and deep-learning (DL) paradigms. Advances such as the application of sophisticated DL architectures for high-density EMG data interpretation, optimization techniques for heightened DL model performance, and the fusion of EMG with electroencephalogram (EEG) signals have been spotlighted for enhancing biomechanical analyses in rehabilitation. The literature survey also categorizes EMG-BF devices based on functionality and clinical usage, supported by insights from commercial sectors. EXPERT OPINION: The current landscape of EMG-BF is rapidly evolving, chiefly propelled by innovations in artificial intelligence (AI). The incorporation of ML and DL into EMG-BF systems augments their accuracy, reliability, and scope, marking a leap in patient care. Despite challenges in model interpretability and signal noise, ongoing research promises to address these complexities, refining biofeedback modalities. The integration of AI not only predicts patient-specific recovery timelines but also tailors therapeutic interventions, heralding a new era of personalized medicine in rehabilitation and emotional detection.

Enhanced nerve function recovery in radial nerve palsy patients with humerus shaft fracture: a randomized study of low-frequency pulse electrical stimulation combined with exercise therapy.

Objective: To evaluate the effect of low-frequency pulse electrical stimulation plus exercise therapy on nerve function recovery in patients with radial nerve palsy after humerus shaft fracture. Methods: A total of 110 patients with humerus shaft fracture and radial nerve injury admitted to our hospital from January 2017 to December 2021 were recruited. They were randomized to receive either conventional exercise therapy (control group) or conventional exercise therapy plus low-frequency pulse electrical stimulation (study group) according to the random number table method, with 55 cases in each. Clinical efficacy, muscle strength recovery, nerve conduction velocity (MCV), amplitude, wrist joint, and elbow joint activities of patients were analyzed and compared. Results: Patients with low frequency stimulation (LFS) showed significantly higher treatment effectiveness (89.09%) than those with exercise therapy only (69.09%). The incorporation of LFS with exercise therapy provided more enhancement in the muscle strength of wrist extensor and total finger extensor in patients when compared with a mere exercise intervention, suggesting better muscle function recovery of patients produced by LFS. Moreover, a significant increase in MCV and its amplitude was observed in all included patients, among which those receiving LFS showed a greater escalation of MCV and its amplitude. Following a treatment duration of 6 months, more patients in the LFS cohort were reported to achieve a wrist extension and elbow extension with an angle over 45° than the controls. There was no notable variance in adverse responses noted between the two patient groups. Conclusion: In patients afflicted with humerus shaft fracture and radial nerve injury, the amalgamation of exercise therapy with low-frequency pulse electrical stimulation can significantly improve clinical efficacy, promote nerve function, and muscle strength recovery, and features a high safety profile. Relevance to clinical practice: The combination of exercise therapy and low-frequency pulsed electrical stimulation can notably improve the promotion of neurologic function and muscle strength recovery in patients with humerus shaft fractures and radial nerve injuries with a high degree of safety.Clinical trial registration:https://www.researchregistry.com, identifier researchregistry9461.

Cyclostationary analysis of uterine EMG measurements for the prediction of preterm birth.

Preterm birth (gestational age < 37 weeks) is a public health concern that causes fetal and maternal mortality and morbidity. When this condition is detected early, suitable treatment can be prescribed to delay labour. Uterine electromyography (uEMG) has gained a lot of attention for detecting preterm births in advance. However, analyzing uEMG is challenging due to the complexities associated with inter and intra-subject variations. This work aims to investigate the applicability of cyclostationary characteristics in uEMG signals for predicting premature delivery. The signals under term and preterm situations are considered from two online datasets. Preprocessing is carried out using a Butterworth bandpass filter, and spectral correlation density function is adapted using fast Fourier transform-based accumulation method (FAM) to compute the cyclostationary variations. The cyclic frequency spectral density (CFSD) and degree of cyclostationarity (DCS) are quantified to assess the existence of cyclostationarity. Features namely, maximum cyclic frequency, bandwidth, mean cyclic frequency (MNCF), and median cyclic frequency (MDCF) are extracted from the cyclostationary spectrum and analyzed statistically. uEMG signals exhibit cyclostationarity property, and these variations are found to distinguish preterm from term conditions. All the four extracted features are noted to decrease from term to preterm conditions. The results indicate that the cyclostationary nature of the signals can provide better characterization of uterine muscle contractions and could be helpful in detecting preterm birth. The proposed method appears to aid in detecting preterm birth, as analysis of uterine contractions under preterm conditions is imperative for timely medical intervention.

Analysis of induced dynamic biceps EMG signal complexity using Markov transition networks.

Purpose: Surface electromyography (sEMG) is a non-invasive technique to characterize muscle electrical activity. The analysis of sEMG signals under muscle fatigue play a crucial part in the branch of neurorehabilitation, sports medicine, biomechanics, and monitoring neuromuscular pathologies. In this work, a method to transform sEMG signals to complex networks under muscle fatigue conditions using Markov transition field (MTF) is proposed. The importance of normalization to a constant Maximum voluntary contraction (MVC) is also considered. Methods: For this, dynamic signals are recorded using two different experimental protocols one under constant load and another referenced to 50% MVC from Biceps brachii of 50 and 45 healthy subjects respectively. MTF is generated and network graph is constructed from preprocesses signals. Features such as average self-transition probability, average clustering coefficient and modularity are extracted. Results: All the extracted features showed statistical significance for the recorded signals. It is found that during the transition from non-fatigue to fatigue, average clustering coefficient decreases while average self-transition probability and modularity increases. Conclusion: The results indicate higher degree of signal complexity during non-fatigue condition. Thus, the MTF approach may be used to indicate the complexity of sEMG signals. Although both datasets showed same trend in results, sEMG signals under 50% MVC exhibited higher separability for the features. The inter individual variations of the MTF features is found to be more for the signals recorded using constant load. The proposed study can be adopted to study the complex nature of muscles under various neuromuscular conditions.

[Tumor-Like Primary Central Nervous System Vasculitis With Spina Involvement:Report of One Case].

Primary central nervous system vasculitis (PACNS) is a vasculitic disorder affecting small to medium-sized blood vessels primarily in the central nervous system,involving the brain,spinal cord,and meninges.Tumor-like PNCAS,a rare subtype of PACNS,is often misdiagnosed as intracranial malignancy,and that with spinal cord involvement is even more uncommon.The lack of specific clinical symptoms and imaging manifestations poses a challenge to the diagnosis of PACNS.This report presents a case of tumor-like PACNS with spinal cord involvement based on the pathological evidence,aiming to enrich the knowledge about this condition.

[Research progress on electromyographic methods for sustained low-intensity muscle fatigue detection].

Sustained low-intensity muscle fatigue (SULMF) refers to the phenomenon that skeletal muscle continues to contract at less than 10% of maximum voluntary contraction during work activities, resulting in decreased muscle contractile function, which is one of the main causes of occupational neck, shoulder, waist and back discomfort and pain symptoms. Although surface electromyography is a key physiological technique for assessing the efficiency of neuromuscular activity, its effectiveness in objectively detecting SULMF remains controversial. Therefore, this paper describes the neurophysiological mechanism and related hypotheses of SULMF, and reviews the research progress of electromyography detection indicators and detection methods of SULMF, which is of great significance for the early prevention and accurate detection of work-related musculoskeletal disorders.

How much does clinical prediagnosis correlate with electrophysiological findings?: a retrospective study.

Background: Electrodiagnostic testing (EDX) is important in the diagnosis and follow-up of neuropathic and myopathic diseases. This study aimed to demonstrate the compatibility between clinical prediagnosis and electrophysiological findings. Methods: EDX results from 2004 to 2020 at the physical medicine and rehabilitation (PM&R) clinic were screened. Tests with missing data, reevaluation studies, and cases of peripheral facial paralysis were excluded. The clinical prediagnosis and EDX results were recorded, and their compatibility was evaluated. Results: A total of 2,153 tests were included in this study. The mean age was 49.0±13.9 years and 1,533 of them (71.2%) were female. The most frequently referred clinic was the PM&R clinic (90.0%). Numbness (73.6%) was the most common complaint, followed by pain (15.3%) and weakness (13.9%). The most common prediagnosis was entrapment neuropathy (55.3%), radiculopathy (16.1%), and polyneuropathy (15.7%). Carpal tunnel syndrome was the most frequently identified type of entrapment neuropathy (78.3%). Six hundred and seventy EDX results (31.1%) were within normal limits. While the EDX results were consistent with the prediagnosis in 1,328 patients (61.7%), a pathology different from the prediagnosis was detected in 155 patients (7.2%). In the discrepancy group, the most common pathologies were entrapment neuropathy (51.7%), polyneuropathy (17.3%), and radiculopathy (15.1%). The most common neuropathy type was carpal tunnel syndrome (79.3%). Conclusion: After adequate anamnesis and physical and neurological examinations, requesting further appropriate tests will increase the prediagnosis accuracy and prevent unnecessary expenditure of time and labor.

The effect of biofeedback on nonneurological dysfunctional voiding in children: A meta-analysis and systematic review.

OBJECTIVE: This study was conducted to investigate the effect of biofeedback (BF) on the rehabilitation of children with nonneurological dysfunctional voiding (NDV). METHODS: RCTs were retrieved from various databases (published from inception to February 29, 2024). The effects of the BF and non-BF treatments were compared. A random-effects model was used to evaluate the combined data. RESULTS: Meta-analysis revealed that BF increased the maximum urinary flow rate (SMD = 3.78, 95% CI 1.33∼6.22), improved urination time (SMD = 5.88, 95% CI 3.75∼8.01), and reduced the postvoid residual (SMD = -19.18, 95% CI -27.03∼-11.33) and urinary tract infection incidence (RR = 0.43, 95% CI 0.21∼0.87). Electromyogram activity (RR = 0.46, 95% CI 0.25∼0.84) and abnormal urination patterns (RR = 0.51, 95% CI 0.35∼0.74) improved, with effects persisting for more than 1 year. However, the effect of BF on the mean urinary flow rate in children with NDV was significant only after 1 year of follow-up (SMD = 1.90, 95% CI 0.87∼2.92). CONCLUSION: Existing evidence indicates that BF can enhance urinary parameters and patterns in children with NDV. However, its effectiveness in addressing constipation, daytime urinary incontinence, and nocturnal urinary incontinence is not substantial. High-quality randomized controlled trials can offer additional insights.

Investigating the effects of ankle foot orthoses on electromyography in impaired populations: a systematic review.

PURPOSE: Despite ample evidence supporting ankle foot orthoses (AFOs) for enhancing ambulation in those with neuromuscular impairment, a prevalent belief among rehabilitation professionals is that AFO use may lead to disuse and reduced muscle activity of the lower leg. To determine the effects of AFO intervention on electromyography (EMG) activity during walking in individuals with neuromuscular impairment. MATERIALS AND METHODS: Five databases were searched for studies that met the predefined inclusion criteria and were published any time through April 2024. AFO design characteristics, muscle groups measured, study design, experimental comparisons, and EMG parameters were extracted from each study. Methodological quality of the included studies was assessed using the modified PEDro scale. RESULTS: Twenty studies met the inclusion criteria. AFO interventions utilized, EMG outcomes utilized, and result interpretations varied widely. In situations of hypertonicity, reduced EMG activity was deemed a positive outcome, while other studies viewed it negatively. Seven longitudinal studies found no adverse long-term impact on EMG activity. CONCLUSION: The results of this review challenge the clinical belief that AFOs cause muscle disuse over time; however, the heterogeneity of AFO designs prevents broad statements related to which orthoses optimize muscle activity.

Ankle foot Orthosis (AFO) intervention demonstrates diverse effects on the timing and amplitude of electromyography (EMG) measures, with significant variability in direction, magnitude, and interpretation across studies, necessitating personalized approaches.Longitudinal studies refute concerns about adverse effects on EMG activity with prolonged AFO use, challenging the notion of decreased muscle activation and supporting the safety of extended AFO utilization.Clinicians are advised to differentiate between peripheral and central nervous system disorders when considering AFO intervention, emphasizing the need to align AFO goals with the patient's clinical presentation and carefully weigh the known advantages associated with AFO utilization.

Diagnostic accuracy of voluntary and stimulated neuromuscular jitter studies in ocular myasthenia gravis.

INTRODUCTION/AIMS: There is a lack of studies comparing the accuracy of neuromuscular jitter analysis during voluntary activation (v-jitter study) versus axonal stimulation (s-jitter study). The study aimed to compare these two techniques in the same population of patients with suspected ocular myasthenia gravis (OMG). METHODS: Fourteen control subjects (mean age: 55.5 ± 15.2 years) and 34 patients with suspected OMG (mean age: 59 ± 13.9 years) were prospectively evaluated. Twenty spike pairs and 30 individual spikes were analyzed during v-jitter and s-jitter study, respectively. Two different criteria for abnormal individual jitter values were evaluated: ≥ or > than 10% values exceeding the upper normal limit. RESULTS: OMG was diagnosed in 19 patients based on clinical and laboratory findings, without considering jitter measurements. In most patients, v-jitter and s-jitter analyses provided comparable results. The maximum sensitivity (89%) was achieved with s-jitter study using the ≥10% criterion, while the maximum specificity (93%) was found with v-jitter study using the >10% criterion. DISCUSSION: Both v-jitter and s-jitter studies showed good to very good accuracy for the diagnosis of OMG, in the absence of any statistically significant difference. Therefore, the patient's cooperation level and examiner's experience should guide the choice of performing v-jitter or s-jitter analysis in patients with suspected OMG.

Influence of restricted mastication on swallowing function.

BACKGROUND: Oral food processing is an important part of daily food intake. A major part of this process is mastication, which prepares a bolus of food for swallowing by mechanically crushing and grinding ingested food between the teeth using rhythmic movements. Masticatory dysfunction is common in the elderly and in some neurological disorders and can have serious negative health consequences. OBJECTIVE: This study investigated the effect of restricted mastication, achieved by experimentally reducing the duration of mastication, on masticatory patterns and subsequent swallowing function. METHODS: Thirty healthy men (25 ± 3 years old) were instructed to chew gum jelly with a free mastication duration (G100), a half and a quarter duration of G100. Masseter and digastric electromyographic (EMG) activity was recorded to assess mastication and swallowing activity, respectively. In addition, the acceleration of the thyroid cartilage ridge was measured with an accelerometer. The root mean square (RMS) of muscle EMG activity in the masseter and digastric muscles, the number of masseter EMG bursts, time to peak and total duration of each masseter EMG burst, swallowing duration and laryngeal elevation latency were analysed. RESULTS: Restricting masticatory duration reduced the number of mastication cycles (p < .001), prolonged the time to peak (p < .001) and total duration of masseter EMG bursts (p < .001) and resulted in an overall increased RMS score of masseter muscle activity (p = .017). Furthermore, restricted masticatory duration led to a decrease in both swallowing duration (p = .001) and laryngeal elevation latency (p = .012), with a significant increase in the RMS score of digastric muscle activity (p < .001). CONCLUSIONS: Under the experimental conditions of restricted mastication, several adaptation features were observed, including changes in masticatory cycle characteristics and swallowing duration. Thus, although the overall masticatory efficiency was reduced, these adaptations allowed healthy individuals to still swallow safely.

Role of neuromuscular blocking agents in the development of polyneuropathy and myopathy in critically ill patients. / Rol de los bloqueantes neuromusculares en el desarrollo de polineuropatía y miopatía del enfermo crítico.

BACKGROUND: Acquired critical illness weakness (AWCIP) is the most frequent neuromuscular disease in intensive care medicine departments. Its importance is given by the prolongation of hospital stay and the delayed recovery it causes to patients after hospitalization. The main objective of this study was to investigate the association between neuromuscular blocking agents and the development of acquired weakness in critically ill patients. MATERIAL AND METHODS: We conducted a prospective study of 103 critically ill patients who were periodically monitored with electromyography. RESULTS: The development of AWCIP was observed in 63 patients. The group of patients who developed AWCIP had a significantly higher utilization of neuromuscular blocking agents than the group who did not develop AWCIP [79.4% vs 50%, OR:3.85 (1.63-9.39), p <0.02]; likewise, this group of patients had a longer ICU stay [32 days vs 14 days, OR: 1.11 (1.06-1.17), p <0. 001] and a longer mechanical ventilation time [24 days vs 9 days, OR:1.2 (1.11-1.32), p <0.001]. CONCLUSION: Neuromuscular blocking agents are a factor associated with the occurrence of AWCIP.

An electrophysiological correlate of sleep in a shark.

Sleep is a prominent physiological state observed across the animal kingdom. Yet, for some animals, our ability to identify sleep can be masked by behaviors otherwise associated with being awake, such as for some sharks that must swim continuously to push oxygenated seawater over their gills to breathe. We know that sleep in buccal pumping sharks with clear rest/activity cycles, such as draughtsboard sharks (Cephaloscyllium isabellum, Bonnaterre, 1788), manifests as a behavioral shutdown, postural relaxation, reduced responsiveness, and a lowered metabolic rate. However, these features of sleep do not lend themselves well to animals that swim nonstop. In addition to video and accelerometry recordings, we tried to explore the electrophysiological correlates of sleep in draughtsboard sharks using electroencephalography (EEG), electromyography, and electrooculography, while monitoring brain temperature. The seven channels of EEG activity had a surprising level of (apparent) instability when animals were swimming, but also when sleeping. The amount of stable EEG signals was too low for replication within- and across individuals. Eye movements were not measurable, owing to instability of the reference electrode. Based on an established behavioral characterization of sleep in draughtsboard sharks, we offer the original finding that muscle tone was strongest during active wakefulness, lower in quietly awake sharks, and lowest in sleeping sharks. We also offer several critical suggestions on how to improve techniques for characterizing sleep electrophysiology in future studies on elasmobranchs, particularly for those that swim continuously. Ultimately, these approaches will provide important insights into the evolutionary confluence of behaviors typically associated with wakefulness and sleep.

Effect of expiratory muscle training on respiratory muscle fatigue in healthy adults: a randomized controlled trial.

[Purpose] This study examined the effects of expiratory muscle training on fatigue in individual respiratory muscles. [Participants and Methods] Healthy adult males (n=31) were randomly assigned to two groups: expiratory muscle training (n=15) and normal controls (n=16). In the expiratory muscle training group, training was performed once for 15 min at 50% load of the maximum expiratory mouth pressure twice daily for 4 weeks. Respiratory muscle fatigue indicators were measured using surface electromyography as the median power frequency of each respiratory muscle at the time of measuring the maximum inspiratory mouth pressure during 20 min of inspiratory muscle loading and maximum expiratory mouth pressure. [Results] In the expiratory muscle training group, the median power frequency values of the sternocleidomastoid, rectus abdominis, and internal oblique/external oblique before expiratory muscle training significantly decreased during inspiratory muscle loading. However, no difference was observed in the median power frequency values measured before and during inspiratory muscle loading after the expiratory muscle training. In the normal controls, the median power frequency values of the sternocleidomastoid and rectus abdominis significantly decreased during inspiratory muscle loading. [Conclusion] Expiratory muscle training increased fatigue tolerance of the sternocleidomastoid, rectus abdominis, and internal and external oblique muscles in healthy individuals.

An Embedded Electromyogram Signal Acquisition Device.

In this study, we design an embedded surface EMG acquisition device to conveniently collect human surface EMG signals, pursue more intelligent human-computer interactions in exoskeleton robots, and enable exoskeleton robots to synchronize with or even respond to user actions in advance. The device has the characteristics of low cost, miniaturization, and strong compatibility, and it can acquire eight-channel surface EMG signals in real time while retaining the possibility of expanding the channel. This paper introduces the design and function of the embedded EMG acquisition device in detail, which includes the use of wired transmission to adapt to complex electromagnetic environments, light signals to indicate signal strength, and an embedded processing chip to reduce signal noise and perform filtering. The test results show that the device can effectively collect the original EMG signal, which provides a scheme for improving the level of human-computer interactions and enhancing the robustness and intelligence of exoskeleton equipment. The development of this device provides a new possibility for the intellectualization of exoskeleton systems and reductions in their cost.

Knee Angle Estimation from Surface EMG during Walking Using Attention-Based Deep Recurrent Neural Networks: Feasibility and Initial Demonstration in Cerebral Palsy.

Accurately estimating knee joint angle during walking from surface electromyography (sEMG) signals can enable more natural control of wearable robotics like exoskeletons. However, challenges exist due to variability across individuals and sessions. This study evaluates an attention-based deep recurrent neural network combining gated recurrent units (GRUs) and an attention mechanism (AM) for knee angle estimation. Three experiments were conducted. First, the GRU-AM model was tested on four healthy adolescents, demonstrating improved estimation compared to GRU alone. A sensitivity analysis revealed that the key contributing muscles were the knee flexor and extensors, highlighting the ability of the AM to focus on the most salient inputs. Second, transfer learning was shown by pretraining the model on an open source dataset before additional training and testing on the four adolescents. Third, the model was progressively adapted over three sessions for one child with cerebral palsy (CP). The GRU-AM model demonstrated robust knee angle estimation across participants with healthy participants (mean RMSE 7 degrees) and participants with CP (RMSE 37 degrees). Further, estimation accuracy improved by 14 degrees on average across successive sessions of walking in the child with CP. These results demonstrate the feasibility of using attention-based deep networks for joint angle estimation in adolescents and clinical populations and support their further development for deployment in wearable robotics.

Facing infant cuteness: How nurturing care motivation and oxytocin system gene methylation are associated with responses to baby schema features.

Baby schema features are a specific set of physical features-including chubby cheeks, large, low-set eyes, and a large, round head-that have evolutionary adaptive value in their ability to trigger nurturant care. In this study among nulliparous women (N = 81; M age = 23.60, SD = 0.44), we examined how sensitivity to these baby schema features differs based on individual variations in nurturant care motivation and oxytocin system gene methylation. We integrated subjective ratings with measures of facial expressions and electroencephalography (EEG) in response to infant faces that were manipulated to contain more or less pronounced baby schema features. Linear mixed effects analyses demonstrated that infants with more pronounced baby schema features were rated as cuter and participants indicated greater motivation to take care of them. Furthermore, infants with more pronounced baby schema features elicited stronger smiling responses and enhanced P2 and LPP amplitudes compared to infants with less pronounced baby schema features. Importantly, individual differences significantly predicted baby schema effects. Specifically, women with low OXTR methylation and high nurturance motivation showed enhanced differentiation in automatic neurophysiological responses to infants with high and low levels of baby schema features. These findings highlight the importance of considering individual differences in continued research to further understand the complexities of sensitivity to child cues, including facial features, which will improve our understanding of the intricate neurobiological system that forms the basis of caregiving behavior.

Intuitive and versatile bionic legs: a perspective on volitional control.

Active lower limb prostheses show large potential to offer energetic, balance, and versatility improvements to users when compared to passive and semi-active devices. Still, their control remains a major development challenge, with many different approaches existing. This perspective aims at illustrating a future leg prosthesis control approach to improve the everyday life of prosthesis users, while providing a research road map for getting there. Reviewing research on the needs and challenges faced by prosthesis users, we argue for the development of versatile control architectures for lower limb prosthetic devices that grant the wearer full volitional control at all times. To this end, existing control approaches for active lower limb prostheses are divided based on their consideration of volitional user input. The presented methods are discussed in regard to their suitability for universal everyday control involving user volition. Novel combinations of established methods are proposed. This involves the combination of feed-forward motor control signals with simulated feedback loops in prosthesis control, as well as online optimization techniques to individualize the system parameters. To provide more context, developments related to volitional control design are touched on.