Recent developments in biofeedback for neuromotor rehabilitation

Effects of Haptic Feedback Interventions in Post-Stroke Gait and Balance Disorders: A Systematic Review and Meta-Analysis

Background: Haptic feedback is an established method to provide sensory information (tactile or kinesthetic) about the performance of an activity that an individual can not consciously detect. After a stroke, hemiparesis usually leads to gait and balance disorders, where haptic feedback can be a promising approach to promote recovery. The aim of the present study is to understand its potential effects on gait and balance impairments, both after interventions and in terms of immediate effects. Methods: This research was carried out using the following scientific databases: Embase, Scopus, Web of Science, and Medline/PubMed from inception to May 2024. The Checklist for Measuring quality, PEDro scale, and the Cochrane collaboration tool were used to assess the methodological quality and risk of bias of the studies. Results: Thirteen articles were chosen for qualitative analysis, with four providing data for the meta-analysis. The findings did not yield definitive evidence on the effectiveness of haptic feedback for treating balance and gait disorders following a stroke. Conclusions: Further research is necessary in order to determine the effectiveness of haptic feedback mechanisms, with larger sample sizes and more robust methodologies. Longer interventions and pre-post design in gait training with haptic feedback are necessary.

Feedback Interventions in Motor Recovery of Lateropulsion after Stroke: A Literature Review and Case Series

Lateropulsion is a post-stroke phenomenon marked by an active push of the body across the midline towards the more affected side and/or a resistance of the weight shift towards the less affected side. Within the mechanisms of treatment, feedback systems have been shown to be effective. The aim of the present study was to create a body of knowledge by performing a literature review on the use of feedback mechanisms in the treatment of lateropulsion and to report two cases of lateropulsion patients who had undergone feedback-based treatment.

METHODS

The review was performed across five different databases (Embase, Medline/PubMed, Scopus, Web of Science, and PEDro) up to February 2024, and haptic feedback intervention was incorporated into the case series (with lateropulsion and ambulation capacity as the main variables).

RESULTS

In total, 211 records were identified and 6 studies were included after the review of the literature. The most used feedback modality was visual feedback. In the case series, positive results were observed from the intervention, particularly in the recovery of lateropulsion and balance, as well as in the improvement of gait for one patient. Patients demonstrated good adherence to the intervention protocol without adverse effects.

CONCLUSIONS

Visual feedback is the most commonly used feedback modality in lateropulsion patients but other mechanisms such as haptic feedback also are feasible and should be taken into account. Larger sample sizes, extended follow-up periods, and the isolation of feedback mechanisms must be established to clarify evidence.

Proportional sway-based electrotactile feedback improves lateral standing balance

Introduction

Plantar cutaneous augmentation is a promising approach in balance rehabilitation by enhancing motion-dependent sensory feedback. The effect of plantar cutaneous augmentation on balance has been mainly investigated in its passive form (e.g., textured insole) or on lower-limb amputees. In this study, we tested the effect of plantar cutaneous augmentation on balance in its active form (i.e., electrical stimulation) for individuals with intact limbs.

Methods

Ten healthy subjects participated in the study and were instructed to maintain their balance as long as possible on the balance board, with or without electrotactile feedback evoked on the medial side of the heel, synched with the lateral board sway. Electrotactile feedback was given in two different modes: 1) Discrete-mode E-stim as the stimulation on/off by a predefined threshold of lateral board sway and 2) Proportional-mode E-stim as the stimulation frequency proportional to the amount of lateral board sway. All subjects were distracted from the balancing task by the n-back counting task, to test subjects' balancing capability with minimal cognitive involvement.

Results

Proportional-mode E-stim, along with the n-back counting task, increased the balance time from 1.86 ± 0.03 s to 1.98 ± 0.04 s (p = 0.010). However, discrete-mode E-stim did not change the balance time (p = 0.669). Proportional-mode E-stim also increased the time duration per each swayed state (p = 0.035) while discrete-mode E-stim did not (p = 0.053).

Discussion

These results suggest that proportional-mode E-stim is more effective than discrete-mode E-stim on improving standing balance. It is perhaps because the proportional electrotactile feedback better mimics the natural tactile sensation of foot pressure than its discrete counterpart.

Efficacy of telerehabilitation with digital and robotic tools for the continuity of care of people with chronic neurological disorders: The TELENEURO@REHAB protocol for a randomized controlled trial

Context

Chronic Neurological Disorders (CNDs) are among the leading causes of disability worldwide, and their contribution to the overall need for rehabilitation is increasing. Therefore, the identification of new digital solutions to ensure early and continuous care is mandatory.

Objective

This protocol proposes to test the usability, acceptability, safety, and efficacy of Telerehabilitation (TR) protocols with digital and robotic tools in reducing the perceived level of disability in CNDs including Parkinson's Disease (PD), Multiple Sclerosis (MS), and post-stroke patients.

Design Setting and Subjects

This single-blinded, multi-site, randomized, two-treatment arms controlled clinical trial will involve PD (N = 30), MS (N = 30), and post-stroke (N = 30). Each participant will be randomized (1:1) to the experimental group (20 sessions of motor telerehabilitation with digital and robotic tools) or the active control group (20 home-based motor rehabilitation sessions according to the usual care treatment). Primary and secondary outcome measures will be obtained at the baseline (T0), post-intervention (T1, 5 weeks after baseline), and at follow-up (T2, 2 months after treatment).

Main Outcome Measures

a multifaceted evaluation including quality of life, motor, and clinical/functional measures will be conducted at each time-point of assessment. The primary outcome measures will be the change in the perceived level of disability as measured by the World Health Organization Disability Assessment Schedule 2.0.

Conclusion

The implementation of TR protocols will enable a more targeted and effective response to the growing need for rehabilitation linked to CNDs, ensuring accessibility to rehabilitation services from the initial stages of the disease.

A deep learning system to monitor and assess rehabilitation exercises in home-based remote and unsupervised conditions

In the domain of physical rehabilitation, the progress in machine learning and the availability of cost-effective motion capture technologies have paved the way for innovative systems capable of capturing human movements, automatically analyzing recorded data, and evaluating movement quality. This study introduces a novel, economically viable system designed for monitoring and assessing rehabilitation exercises. The system enables real-time evaluation of exercises, providing precise insights into deviations from correct execution. The evaluation comprises two significant components: range of motion (ROM) classification and compensatory pattern recognition. To develop and validate the effectiveness of the system, a unique dataset of 6 resistance training exercises was acquired. The proposed system demonstrated impressive capabilities in motion monitoring and evaluation. Notably, we achieved promising results, with mean accuracies of 89% for evaluating ROM-class and 98% for classifying compensatory patterns. By complementing conventional rehabilitation assessments conducted by skilled clinicians, this cutting-edge system has the potential to significantly improve rehabilitation practices. Additionally, its integration in home-based rehabilitation programs can greatly enhance patient outcomes and increase access to high-quality care.

Monitoring Active Patient Participation During Robotic Rehabilitation: Comparison Between a Robot-Based Metric and an EMG-Based Metric

While rehabilitation robots present a much-needed solution to improving early mobilization therapy in demanding clinical settings, they also present new challenges and opportunities in patient monitoring. Aside from the fundamental challenge of quantifying a patient's voluntary contribution during robot-led therapy motion, many sensors cannot be used in clinical settings due to time and space limitations. In this paper, we present and compare two metrics for monitoring a patient's active participation in the motion. The two metrics, each derived from first principles, have the same biomechanical interpretability, i.e., active work by the patient during the robotic mobilization therapy, but are calculated in two different spaces (Cartesian vs. muscle space). Furthermore, the sensors used to quantify these two metrics are fully independent from each other and the associated measurements are unrelated. Specifically, the robot-based work metric utilizes robot-integrated force sensors, while the EMG-based work metric requires electrophysiological sensors. We then apply the two metrics to therapy performed using a clinically certified, commercially available robotic system and compare them against the specific instructions given to the healthy subjects as well as against each other. Both metric outputs qualitatively match the expected behavior of the healthy subjects. Additionally, strong correlations (median [Formula: see text]) are shown between the two metrics, not only for healthy subjects (n = 12) but also for patients (n = 2), providing solid evidence for their validity and translatability. Importantly, the robot-based work metric does not rely on any sensors outside of those integrated into the robot, thus making it ideal for application in clinical settings.

A Systematic Review of the Long-Term Effects of Using Smartphone- and Tablet-Based Rehabilitation Technology for Balance and Gait Training and Exercise Programs

Recent advances in wearable motion sensors, mobile devices, the Internet of Things, and telecommunications have created new potential for telerehabilitation. Recognizing that there is no systematic review of smartphone- or tablet-based balance and gait telerehabilitation technology for long-term use (i.e., four weeks or more), this systematic review summarizes the effects of smartphone- or tablet-based rehabilitation technology on balance and gait exercise and training in balance and gait disorders. The review examined studies written in English published from 2013 to 2023 in Web of Science, Pubmed, Scopus, and Google Scholar. Of the 806 studies identified, 14 were selected, and the National Institutes of Health Quality Assessment Tool for Observational Cohort and Cross-sectional Studies was applied to evaluate methodological quality. The systematic review concluded that all 14 studies found balance and gait performance improvement after four weeks or more of balance and gait telerehabilitation. Ten of the 14 studies found that carry-over effects (improved functional movements, muscle strength, motor capacity, cognition, and reduced fear of falling and anxiety levels) were maintained for weeks to months. The results of the systematic review have positive technical and clinical implications for the next-generation design of rehabilitation technology in balance and gait training and exercise programs.

Biofeedback interventions for short term upper limb function following stroke: A systematic review with meta-analysis

BACKGROUND

Biofeedback has been used by rehabilitation professionals in the treatment of poststroke function impairments.

PURPOSE

Investigate the efficacy of any type of biofeedback intervention for the treatment of upper limb function in individuals following stroke.

STUDY DESIGN

Systematic review of literature with meta-analysis.

METHODS

Literature searches were conducted using MESH terms and text words in PubMed, Lilacs, Scielo, Scopus, PEDro, and Web of Science databases. The main outcome was improvement in upper limb's motor function and motor function in activities of daily living. We calculated the Mean Difference and Standardized Mean Difference for the assessment scales reported as primary outcome. The methodological quality of included studies was assessed using PEDro scale. The overall quality of the evidence was assessed using GRADE system.

RESULTS

From 1360 articles identified, 16 were included in the review (09 in the meta-analysis). Three forest plots of hemiparesis and one of hemiplegia showed that biofeedback therapy associated with conventional therapy has a greater improvement in participants upper limb motor function when compared to isolated conventional therapy. Two forest plots of hemiparesis and one of hemiplegia showed no superiority in participants improvement for biofeedback associated with conventional therapy when compared to isolated conventional therapy.

CONCLUSION

Biofeedback therapy associated with conventional therapy showed a small clinical effect when associated to conventional therapy and very low quality of evidence. Although further research with higher quality evidence is needed.

Compare the Effect of Traditional and Virtual Reality Training on Subjective-sense of Instability and Balance in Basketball-players with Functional Ankle Instability: Matched Randomized Clinical Trial

Background

Functional ankle instability (FAI) is a common injury. Traditional training improved the reported balance impairment and subjective sense of instability in athletes with FAI.

Objective

This study aims to compare the effects of traditional and virtual reality training on a subjective sense of instability and balance in athlete with FAI.

Material and Methods

In this single-blinded matched randomized clinical trial design, Fifty-four basketball players were randomly assigned in the virtual reality (n=27) or control (n=27) groups. All athletes performed 12 sessions Wii exercises or traditional training in the virtual reality and the control group, respectively, for three days a week. To assess the subjective-sense of instability and balance, we used Cumberland Ankle Instability Tool (CAIT) and Star Excursion Balance Test (SEBT), respectively. Measures were taken at pre- and post-test and one month after training as a follow-up. The between-group comparisons were done by the analysis of Covariance.

Results

At the pre-test, the CAIT score was 22.37, 22.04 in the control and virtual reality groups, respectively and at the post-test, these scores increased to 26.63, 27.26. The involved limb showed significant differences in posteromedial and posterior directions of the SEBT and CAIT score in the post-test and in the posterior direction and CAIT score in the follow-up. The virtual reality group had better performance than the control group but the effect size is small (cohen's d<0.2).

Conclusion

Based on our results, both training protocols were effective in reducing the subjective-sense of instability and improved balance in athletes with FAI. Moreover, virtual reality training was very attractive for the participants.

Motor control complexity can be dynamically simplified during gait pattern exploration using motor control-based biofeedback

Understanding how the central nervous system coordinates diverse motor outputs has been a topic of extensive investigation. Although it is generally accepted that a small set of synergies underlies many common activities, such as walking, whether synergies are equally robust across a broader array of gait patterns or can be flexibly modified remains unclear. Here, we evaluated the extent to which synergies changed as nondisabled adults (n = 14) explored gait patterns using custom biofeedback. Secondarily, we used Bayesian additive regression trees to identify factors that were associated with synergy modulation. Participants explored 41.1 ± 8.0 gait patterns using biofeedback, during which synergy recruitment changed depending on the type and magnitude of gait pattern modification. Specifically, a consistent set of synergies was recruited to accommodate small deviations from baseline, but additional synergies emerged for larger gait changes. Synergy complexity was similarly modulated; complexity decreased for 82.6% of the attempted gait patterns, but distal gait mechanics were strongly associated with these changes. In particular, greater ankle dorsiflexion moments and knee flexion through stance, as well as greater knee extension moments at initial contact, corresponded to a reduction in synergy complexity. Taken together, these results suggest that the central nervous system preferentially adopts a low-dimensional, largely invariant control strategy but can modify that strategy to produce diverse gait patterns. Beyond improving understanding of how synergies are recruited during gait, study outcomes may also help identify parameters that can be targeted with interventions to alter synergies and improve motor control after neurological injury.NEW & NOTEWORTHY We used a motor control-based biofeedback system and machine learning to characterize the extent to which nondisabled adults can modulate synergies during gait pattern exploration. Results revealed that a small library of synergies underlies an array of gait patterns but that recruitment from this library changes as a function of the imposed biomechanical constraints. Our findings enhance understanding of the neural control of gait and may inform biofeedback strategies to improve synergy recruitment after neurological injury.

Current developments in surface electromyography

Background/aim

Surface electromyography (surface EMG) is a primary technique to detect the electrical activities of muscles through surface electrodes. In recent years, surface EMG applications have grown from conventional fields into new fields. However, there is a gap between the progress in the research of surface EMG and its clinical acceptance, characterized by the translational knowledge and skills in the widespread use of surface EMG among the clinician community. To reduce this gap, it is necessary to translate the updated surface EMG applications and technological advances into clinical research. Therefore, we aimed to present a perspective on recent developments in the application of surface EMG and signal processing methods.

Materials and methods

We conducted this scoping review following the Joanna Briggs Institute (JBI) method. We conducted a general search of PubMed and Web of Science to identify key search terms. Following the search, we uploaded selected articles into Rayyan and removed duplicates. After prescreening 133 titles and abstracts, we assessed 91 full texts according to the inclusion criteria.

Results

We concluded that surface EMG has made innovative technological progress and has research potential for routine clinical applications and a wide range of applications, such as neurophysiology, sports and art performances, biofeedback, physical therapy and rehabilitation, assessment of physical exercises, muscle strength, fatigue, posture and postural control, movement analysis, muscle coordination, motor synergies, modelling, and more. Novel methods have been applied for surface EMG signals in terms of time domain, frequency domain, time-frequency domain, statistical methods, and nonlinear methods.

Conclusion

Translating innovations in surface EMG and signal analysis methods into routine clinical applications can be a helpful tool with a growing and valuable role in muscle activation measurement in clinical practices. Thus, researchers must build many more interfaces that give opportunities for continuing education and research with more contemporary techniques and devices.

Interaction with a Hand Rehabilitation Exoskeleton in EMG-Driven Bilateral Therapy: Influence of Visual Biofeedback on the Users' Performance

The effectiveness of EMG biofeedback with neurorehabilitation robotic platforms has not been previously addressed. The present work evaluates the influence of an EMG-based visual biofeedback on the user performance when performing EMG-driven bilateral exercises with a robotic hand exoskeleton. Eighteen healthy subjects were asked to perform 1-min randomly generated sequences of hand gestures (rest, open and close) in four different conditions resulting from the combination of using or not (1) EMG-based visual biofeedback and (2) kinesthetic feedback from the exoskeleton movement. The user performance in each test was measured by computing similarity between the target gestures and the recognized user gestures using the L2 distance. Statistically significant differences in the subject performance were found in the type of provided feedback (p-value 0.0124). Pairwise comparisons showed that the L2 distance was statistically significantly lower when only EMG-based visual feedback was present (2.89 ± 0.71) than with the presence of the kinesthetic feedback alone (3.43 ± 0.75, p-value = 0.0412) or the combination of both (3.39 ± 0.70, p-value = 0.0497). Hence, EMG-based visual feedback enables subjects to increase their control over the movement of the robotic platform by assessing their muscle activation in real time. This type of feedback could benefit patients in learning more quickly how to activate robot functions, increasing their motivation towards rehabilitation.

Does Cueing Need Attention? A Pilot Study in People with Parkinson's Disease

We previously showed that both open-loop (beat of a metronome) and closed-loop (phase-dependent tactile feedback) cueing may be similarly effective in reducing Freezing of Gait (FoG), assessed with a quantitative FoG Index, while turning in place in the laboratory in a group of people with Parkinson's disease (PD). Despite the similar changes on the FoG Index, it is not known whether both cueing responses require attentional control, which would explain FoG Index improvement. The mechanisms underlying cueing responses are poorly understood. Here, we tested the hypothesis that the salience network would predict responsiveness (i.e., FoG Index improvement) to open-loop and closed-loop cueing in people with and without FoG of PD, as salience network contributes to tasks requiring attention to external stimuli in healthy adults. Thirteen people with PD with high-quality imaging data were analyzed to characterize relationships between resting-state MRI functional connectivity and responses to cues. The interaction of the salience network and retrosplenial-temporal networks was the best predictor of responsiveness to open-loop cueing, presenting the largest effect size (d = 1.16). The interaction between the salience network and subcortical as well as cingulo-parietal and subcortical networks were the strongest predictors of responsiveness to closed-loop cueing, presenting the largest effect sizes (d = 1.06 and d = 0.84, respectively). Salience network activity was a common predictor of responsiveness to both cueing, which suggests that auditory and proprioceptive stimuli during turning may require some level of cognitive and insular activity, anchored within the salience network, which explain FoG Index improvements in people with PD.

Robotic Biofeedback for Post-Stroke Gait Rehabilitation: A Scoping Review

This review aims to recommend directions for future research on robotic biofeedback towards prompt post-stroke gait rehabilitation by investigating the technical and clinical specifications of biofeedback systems (BSs), including the complementary use with assistive devices and/or physiotherapist-oriented cues. A literature search was conducted from January 2019 to September 2022 on Cochrane, Embase, PubMed, PEDro, Scopus, and Web of Science databases. Data regarding technical (sensors, biofeedback parameters, actuators, control strategies, assistive devices, physiotherapist-oriented cues) and clinical (participants' characteristics, protocols, outcome measures, BSs' effects) specifications of BSs were extracted from the relevant studies. A total of 31 studies were reviewed, which included 660 stroke survivors. Most studies reported visual biofeedback driven according to the comparison between real-time kinetic or spatiotemporal data from wearable sensors and a threshold. Most studies achieved statistically significant improvements on sensor-based and clinical outcomes between at least two evaluation time points. Future research should study the effectiveness of using multiple wearable sensors and actuators to provide personalized biofeedback to users with multiple sensorimotor deficits. There is space to explore BSs complementing different assistive devices and physiotherapist-oriented cues according to their needs. There is a lack of randomized-controlled studies to explore post-stroke stage, mental and sensory effects of BSs.

Combined spatial and frequency encoding for electrotactile feedback of myoelectric signals

Electrotactile stimulation has been commonly used in human–machine interfaces to provide feedback to the user, thereby closing the control loop and improving performance. The encoding approach, which defines the mapping of the feedback information into stimulation profiles, is a critical component of an electrotactile interface. Ideally, the encoding will provide a high-fidelity representation of the feedback variable while being easy to perceive and interpret by the subject. In the present study, we performed a closed-loop experiment wherein discrete and continuous coding schemes are combined to exploit the benefits of both techniques. Subjects performed a muscle activation-matching task relying solely on electrotactile feedback representing the generated myoelectric signal (EMG). In particular, we investigated the performance of two different coding schemes (spatial and spatial combined with frequency) at two feedback resolutions (low: 3 and high: 5 intervals). In both schemes, the stimulation electrodes were placed circumferentially around the upper arm. The magnitude of the normalized EMG was divided into intervals, and each electrode was associated with one interval. When the generated EMG entered one of the intervals, the associated electrode started stimulating. In the combined encoding, the additional frequency modulation of the active electrode also indicated the momentary magnitude of the signal within the interval. The results showed that combined coding decreased the undershooting rate, variability and absolute deviation when the resolution was low but not when the resolution was high, where it actually worsened the performance. This demonstrates that combined coding can improve the effectiveness of EMG feedback, but that this effect is limited by the intrinsic variability of myoelectric control. Our findings, therefore, provide important insights as well as elucidate limitations of the information encoding methods when using electrotactile stimulation to convey a feedback signal characterized by high variability (EMG biofeedback).

The influence of a vibrotactile biofeedback system on postural dynamics during single-leg standing in healthy older adults

The effectiveness of sensory substitution technology, such as haptic-based vibrotactile biofeedback (VBF), has been verified for balance training and rehabilitation. However, whether VBF training changes postural dynamics in older people remains unknown. This study investigated the influence of VBF training on postural dynamics during single-leg standing in older adults, using detrended fluctuation analysis (DFA). Twenty older adults participated in this study. Measurement of postural sway comprised three phases: first measurement session as a baseline test, postural training (day 1), and second measurement session (day 2). The BF group received BF training during the balance training session, while the control group practiced single-leg stance without BF. The center of pressure (CoP) trajectory was recorded in the first measurement session (pre) and second measurement session (post) at 50 Hz. DFA revealed the presence of two linear scaling regions in the CoP, indicating the presence of fast- and slow-scale fluctuations. For the BF group, slow-scale postural dynamics revealed more anti-persistent behavior after training in the anterior-posterior direction. However, the control group showed a change toward more random dynamics after training. These different influences suggest that the BF system might improve error correction strategies during single-leg standing for older adults, while single-leg standing training without the BF system might cause the loss of controllability in single-leg standing. Further, the results of the DFA are discussed in the context of balance training using VBF.

Preliminary Study of Vibrotactile Feedback during Home-Based Balance and Coordination Training in Individuals with Cerebellar Ataxia

Intensive balance and coordination training is the mainstay of treatment for symptoms of impaired balance and mobility in individuals with hereditary cerebellar ataxia. In this study, we compared the effects of home-based balance and coordination training with and without vibrotactile SA for individuals with hereditary cerebellar ataxia. Ten participants (five males, five females; 47  ±  12 years) with inherited forms of cerebellar ataxia were recruited to participate in a 12-week crossover study during which they completed two six-week blocks of balance and coordination training with and without vibrotactile SA. Participants were instructed to perform balance and coordination exercises five times per week using smartphone balance trainers that provided written, graphic, and video guidance and measured trunk sway. The pre-, per-, and post-training performance were assessed using the Scale for the Assessment and Rating of Ataxia (SARA), SARAposture&gait sub-scores, Dynamic Gait Index, modified Clinical Test of Sensory Interaction in Balance, Timed Up and Go performed with and without a cup of water, and multiple kinematic measures of postural sway measured with a single inertial measurement unit placed on the participants’ trunks. To explore the effects of training with and without vibrotactile SA, we compared the changes in performance achieved after participants completed each six-week block of training. Among the seven participants who completed both blocks of training, the change in the SARA scores and SARAposture&gait sub-scores following training with vibrotactile SA was not significantly different from the change achieved following training without SA (p>0.05). However, a trend toward improved SARA scores and SARAposture&gait sub-scores was observed following training with vibrotactile SA; compared to their pre-vibrotacile SA training scores, participants significantly improved their SARA scores (mean=−1.21, p=0.02) and SARAposture&gait sub-scores (mean=−1.00, p=0.01). In contrast, no significant changes in SARA scores and SARAposture&gait sub-scores were observed following the six weeks of training without SA compared to their pre-training scores immediately preceding the training block without vibrotactile SA (p>0.05). No significant changes in trunk kinematic sway parameters were observed as a result of training (p>0.05). Based on the findings from this preliminary study, balance and coordination training improved the participants’ motor performance, as captured through the SARA. Vibrotactile SA may be a beneficial addition to training regimens for individuals with hereditary cerebellar ataxia, but additional research with larger sample sizes is needed to assess the significance and generalizability of these findings.

Effects of Vibrotactile Biofeedback Providing Real-Time Pressure Information on Static Balance Ability and Weight Distribution Symmetry Index in Patients with Chronic Stroke

Training with visual and auditory biofeedback, in patients with stroke, improved balance ability and asymmetric posture. We developed a new biofeedback training device to prevent falls and improve balance ability in patients with stroke. This device corrects motion errors by collecting the pressure information of patients in real-time. This randomized crossover study aimed to investigate the effect of this biofeedback training on the static balance ability and weight distribution symmetry index in 24 patients with chronic stroke. Pressure sensor-based vibrotactile biofeedback, visual biofeedback providing posture information, and standing without biofeedback were randomly applied for 1 d each with 24 h washout intervals to minimize adaptation. The static balance ability was measured for each biofeedback training type, and the weight distribution symmetry index was calculated using the collected weight-bearing rate data. The static balance ability and weight distribution symmetry index differed significantly according to the type of biofeedback training used. Post-hoc analysis revealed significant differences in the order of newly developed vibrotactile biofeedback, visual biofeedback, and standing without biofeedback. These findings provide evidence that pressure sensor-based vibrotactile biofeedback improves static balance ability and weight support rates by proposing better intervention for patients with chronic stroke in the clinical environment.

Somesthetic, Visual, and Auditory Feedback and Their Interactions Applied to Upper Limb Neurorehabilitation Technology: A Narrative Review to Facilitate Contextualization of Knowledge

Reduced hand dexterity is a common component of sensorimotor impairments for individuals after stroke. To improve hand function, innovative rehabilitation interventions are constantly developed and tested. In this context, technology-based interventions for hand rehabilitation have been emerging rapidly. This paper offers an overview of basic knowledge on post lesion plasticity and sensorimotor integration processes in the context of augmented feedback and new rehabilitation technologies, in particular virtual reality and soft robotic gloves. We also discuss some factors to consider related to the incorporation of augmented feedback in the development of technology-based interventions in rehabilitation. This includes factors related to feedback delivery parameter design, task complexity and heterogeneity of sensory deficits in individuals affected by a stroke. In spite of the current limitations in our understanding of the mechanisms involved when using new rehabilitation technologies, the multimodal augmented feedback approach appears promising and may provide meaningful ways to optimize recovery after stroke. Moving forward, we argue that comparative studies allowing stratification of the augmented feedback delivery parameters based upon different biomarkers, lesion characteristics or impairments should be advocated (e.g., injured hemisphere, lesion location, lesion volume, sensorimotor impairments). Ultimately, we envision that treatment design should combine augmented feedback of multiple modalities, carefully adapted to the specific condition of the individuals affected by a stroke and that evolves along with recovery. This would better align with the new trend in stroke rehabilitation which challenges the popular idea of the existence of an ultimate good-for-all intervention.

The Application of Biological Feedback in the Rehabilitation of Patients after Ischemic Stroke

Balance disorders are the main concern for patients after an ischemic stroke. They are caused by an abnormal force on the affected side or paresis, which causes uneven loading and visuospatial disorders. Minimizing the effects of stroke is possible through properly conducted rehabilitation. One of the known ways to achieve this objective is biological feedback. The lack of proper muscle tone on one side of the body is manifested by the uneven pressure of the lower extremities on the ground. The study and control groups were composed of two equal groups of 92 people each, in which the same set of kinesiotherapeutic exercises were applied. Patients in the study group, in addition to standard medical procedures, exercised five days a week on a Balance Trainer for four weeks. The examination and training with the device were recorded on the first day of rehabilitation, as well as after two and four weeks of training. The assessment was performed using the following functional tests and scales: Brunnström, Rankin, Barthel, Ashworth, and VAS. Patients in the control group started exercising on the Balance Trainer two weeks after the first day of rehabilitation using traditional methods. The study results reveal statistically significant reductions in the time the body’s center of gravity (COG) spent in the tacks, outside the tracks and in the COG distance, lower COG excursions in all directions. Post-stroke patients that received biofeedback training presented significantly better results than patients that did not receive such training.

Comparison of the effects of Wii and conventional training on functional abilities and neurocognitive function in basketball-players with functional ankle instability: Matched randomized clinical trial

OBJECTIVE

To compare the effects of Wii and conventional training on functional abilities and neurocognitive function in basketball-players with Functional Ankle Instability (FAI).

DESIGN

Single-blind matched randomized clinical trial study.

SETTING

Outpatients setting.

PARTICIPANTS

Fifty-four basketball-players were randomly assigned to the Wii and control group.

INTERVENTIONS

All athletes in the Wii group (n = 27) performed Wii Fit Plus games; and in the control group (n = 27), they performed conventional training three days a week for 12 sessions.

MAIN OUTCOME MEASURES

To assess functional performance and neurocognitive function, we used hop tests (8-hop, side hop, and single hop) and Deary-Liewald Reaction Time Task (DLRT), respectively. DLRT measured simple and choice reaction time and error rate. Measures were taken at baseline, four weeks, and eight weeks after baseline.

RESULTS

In all 54 athletes completed the study. The results showed no significant differences for all hop tests in between-group comparison but the neurocognitive function showed significant improvements in the Wii group compared to the control group (P < 0.05). Mean (SD) for 8-hop and side hop tests for the involved limb, and simple and choice reaction time four weeks after baseline in the control group were 10.15 (1.02), 12.36 (1.31), and 339.10 (41.57), 530.52 (53.36), respectively and in the Wii group, were 10.46 (1.23), 12.40 (1.31), and 295.25 (13.16), 431.19 (33.46), respectively.

CONCLUSION

Based on our results, both training protocols were equal to positively affect functional abilities. Besides, Wii training improved neurocognitive function and can be applied in FAI rehabilitation protocols.

Acute Vibration Feedback During Gait Reduces Mechanical Ankle Joint Loading in Chronic Ankle Instability Patients

BACKGROUND

Individuals with chronic ankle instability (CAI) exhibit altered vertical ground reaction forces (vGRF), a laterally shifted center of pressure, and an inverted foot position during walking. These neuromechanical alterations are linked with altered ankle joint loading in this population. Vibration-based gait retraining improves center of pressure positioning but effects on neuromechanical variables influencing joint loading remains unknown.

RESEARCH QUESTION

Do patients with CAI exhibit altered vGRF and ankle joint contact forces (JCF) after receiving a single session of vibration-based gait retraining?

METHODS

Ten individuals with CAI underwent a single session of vibration-based gait retraining. Kinematic and kinetic data were collected during walking on an instrumental treadmill with force plates embedded in it. Following a baseline gait assessment without feedback, participants walked at a self-selected speed for 10 minutes while receiving feedback. Data was collected during an early (1 st and 2 nd minute) and late adaptation phase (9 th and 10 th minute) and, compared to baseline values. Impact and propulsive vGRF variables (i.e. peak, time to peak, and loading rate) were obtained. Musculoskeletal modeling was used to calculate ankle JCF variables (peak, impulse, and loading rate) during stance phase.

RESULTS

Propulsive vGRF and ankle JCF outcomes were significantly reduced during the early and late adaptation phases (p ≤ 0.039).

SIGNIFICANCE

These results indicate that vibration-based gait retraining can immediately reduce propulsive vGRF and ankle JCF and may represent a modality that could help restore appropriate ankle joint loading patterns in those with CAI.

How adaptation, training, and customization contribute to benefits from exoskeleton assistance

Exoskeletons can enhance human mobility, but we still know little about why they are effective. For example, we do not know the relative importance of training, how much is required, or what type is most effective; how people adapt with the device; or the relative benefits of customizing assistance. We conducted experiments in which naïve users learned to walk with ankle exoskeletons under one of three training regimens characterized by different levels of variation in device behavior. Assistance was also customized for one group. After moderate-variation training, the benefits of customized assistance were large; metabolic rate was reduced by 39% compared with walking with the exoskeleton turned off. Training contributed about half of this benefit and customization about one-quarter; a generic controller reduced energy cost by 10% before training and 31% afterward. Training required much more exposure than typical of exoskeleton studies, about 109 minutes of assisted walking. Type of training also had a strong effect; the low-variation group required twice as long as the moderate-variation group to become expert, and the high-variation group never acquired this level of expertise. Curiously, all users adapted in a way that resulted in less mechanical power from the exoskeleton as they gained expertise. Customizing assistance required less time than training for all parameters except peak torque magnitude, which grew slowly over the study, suggesting a longer time scale adaptation in the person. These results underscore the importance of training to the benefits of exoskeleton assistance and suggest the topic deserves more attention.

A new integrated behavioural intervention for knee osteoarthritis: development and pilot study

Background

Exercise-based approaches have been a cornerstone of physiotherapy management of knee osteoarthritis for many years. However, clinical effects are considered small to modest and the need for continued adherence identified as a barrier to clinical efficacy. While exercise-based approaches focus on muscle strengthening, biomechanical research has identified that people with knee osteoarthritis over activate their muscles during functional tasks. Therefore, we aimed to create a new behavioural intervention, which integrated psychologically informed practice with biofeedback training to reduce muscle overactivity, and which was suitable for delivery by a physiotherapist.

Methods

Through literature review, we created a framework linking theory from pain science with emerging biomechanical concepts related to overactivity of the knee muscles. Using recognised behaviour change theory, we then mapped a set of intervention components which were iteratively developed through ongoing testing and consultation with patients and physiotherapists.

Results

The underlying framework incorporated ideas related to central sensitisation, motor responses to pain and also focused on the idea that increased knee muscle overactivity could result from postural compensation. Building on these ideas, we created an intervention with five components: making sense of pain, general relaxation, postural deconstruction, responding differently to pain and functional muscle retraining. The intervention incorporated a range of animated instructional videos to communicate concepts related to pain and biomechanical theory and also used EMG biofeedback to facilitate visualization of muscle patterns. User feedback was positive with patients describing the intervention as enabling them to “create a new normal” and to be “in control of their own treatment.” Furthermore, large reductions in pain were observed from 11 patients who received a prototype version of the intervention.

Conclusion

We have created a new intervention for knee osteoarthritis, designed to empower individuals with capability and motivation to change muscle activation patterns and beliefs associated with pain. We refer to this intervention as Cognitive Muscular Therapy. Preliminary feedback and clinical indications are positive, motivating future large-scale trials to understand potential efficacy. It is possible that this new approach could bring about improvements in the pain associated with knee osteoarthritis without the need for continued adherence to muscle strengthening programmes.

Trial registration

ISRCTN51913166 (Registered 24-02-2020, Retrospectively registered).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04389-0.

Effect of Deep Cervical Flexor Muscle Training Using Pressure Biofeedback on Pain and Forward Head Posture in School Teachers with Neck Pain: An Observational Study

BACKGROUND

Teaching is one of the professions where incidence and prevalence of neck pain is high. Prolonged use of computers, which has further increased due to online teaching amid pandemic, is known to cause neck pain and alter posture, while people with forward head posture (FHP) are prone to develop neck pain and related disability. Research has shown that impairment of deep cervical flexor (DCF) muscles leads to insufficiency in coordination, activation, overload, and poor support on cervical structures that further lead to development of neck pain and altered neck posture. The objective of this study was to see the effect of DCF muscle training using pressure biofeedback on pain and FHP in school teachers with neck pain.

METHODS

This observational study was conducted at medical center in school premises. Fifty-five school teachers aged between 25 and 40 years with experience of more than 5 years were invited to participate in this study. Subjects were divided in two groups. Both the groups received conventional exercises while in experimental group DCF muscle training using pressure biofeedback was given additionally. Pain and FHP were assessed using NPRS and cranio-vertebral angle using digital photograph technique, respectively, at baseline and end of four weeks of treatment.

RESULTS

Although pain and FHP improved in both the groups, mean improvement in both the measures was more in the group that also received DCF training using pressure biofeedback.

CONCLUSIONS

This study shows that although pain and FHP improved following conventional exercises in school teachers with neck pain, mean improvement was more significant among those who received additional DCF muscle training using pressure biofeedback.

Sitting Posture during Prolonged Computer Typing with and without a Wearable Biofeedback Sensor

Prolonged sitting combined with an awkward posture might contribute to the increased risks of developing spinal pain. Maintaining an upright sitting posture is thus often suggested, especially nowadays when people spend longer periods in the sitting posture for occupational or leisure activities. Many types of assistive devices are commercially available to help computer users maintain an upright sitting posture. As the technology advances, wearable sensors that use microelectromechanical technology are designed to provide real-time biofeedback and promote adjusting posture actively. However, whether such wearable biofeedback sensors could assist adjusting sitting posture in computer users during prolonged typing remains unknown. This study aimed to investigate the effects of a wearable biofeedback sensor on maintaining an upright sitting posture. Twenty-one healthy young adults were recruited and performed a 1-h computer typing task twice, with and without using the active biofeedback device. The sagittal spinal posture during computer typing was measured using a three-dimensional motion analysis system. Using the wearable biofeedback sensor significantly decreased the neck flexion (p < 0.001), thoracic kyphotic (p = 0.033), and pelvic plane (p = 0.021) angles compared with not using the sensor. Computer users and sedentary workers may benefit from using wearable biofeedback sensors to actively maintain an upright sitting posture during prolonged deskwork.

Differentiation among bio- and augmented- feedback in technologically assisted rehabilitation

Introduction: In rehabilitation practice, the term 'feedback' is often improperly used, with augmented feedback and biofeedback frequently confused, especially when referring to the human-machine interaction during technologically assisted training. The absence of a clear differentiation between these categories represents an unmet need for rehabilitation, emphasized by the advent of new technologies making extensive use of video feedback, exergame, and virtual reality.Area covered: In this review we tried to present scientific knowledge about feedback, biofeedback, augmented feedback and neurofeedback, and related differences in rehabilitation settings, for a more proper use of this terminology. Despite the continuous expansion of the field, few researches clarify the differences among these terms. This scoping review was conducted through the searching of current literature up to May 2020, using following databases: PUBMED, EMBASE and Web of Science. After literature search a classification system, distinguishing feedback, augmented feedback, and biofeedback, was applied.Expert opinion: There is a need for clear definitions of feedback, biofeedback, augmented feedback, and neurofeedback in rehabilitation, especially in the technologically assisted one based on human-machine interaction. In fact, the fast development of new technologies requires to be based on solid concepts and on a common terminology shared among bioengineers and clinicians.

Wearable Devices for Biofeedback Rehabilitation: A Systematic Review and Meta-Analysis to Design Application Rules and Estimate the Effectiveness on Balance and Gait Outcomes in Neurological Diseases

Wearable devices are used in rehabilitation to provide biofeedback about biomechanical or physiological body parameters to improve outcomes in people with neurological diseases. This is a promising approach that influences motor learning and patients' engagement. Nevertheless, it is not yet clear what the most commonly used sensor configurations are, and it is also not clear which biofeedback components are used for which pathology. To explore these aspects and estimate the effectiveness of wearable device biofeedback rehabilitation on balance and gait, we conducted a systematic review by electronic search on MEDLINE, PubMed, Web of Science, PEDro, and the Cochrane CENTRAL from inception to January 2020. Nineteen randomized controlled trials were included (Parkinson's n = 6; stroke n = 13; mild cognitive impairment n = 1). Wearable devices mostly provided real-time biofeedback during exercise, using biomechanical sensors and a positive reinforcement feedback strategy through auditory or visual modes. Some notable points that could be improved were identified in the included studies; these were helpful in providing practical design rules to maximize the prospective of wearable device biofeedback rehabilitation. Due to the current quality of the literature, it was not possible to achieve firm conclusions about the effectiveness of wearable device biofeedback rehabilitation. However, wearable device biofeedback rehabilitation seems to provide positive effects on dynamic balance and gait for PwND, but higher-quality RCTs with larger sample sizes are needed for stronger conclusions.

Lower limb biomechanics in individuals with chronic ankle instability during gait: a case-control study

Background

Individuals with chronic ankle instability (CAI) exhibit many biomechanical changes to lower limbs during walking. However, only a few studies have investigated the differences in lower limb biomechanics of individuals with CAI compared to healthy controls using a comprehensive approach including kinematic, kinetic and electromyography (EMG) measures. Consequently, the theoretical framework explaining the biomechanical adaptations in individuals with CAI is mostly based on the results of studies including heterogenous methods and participants’ specificities (e.g., level of disability). More studies using a comprehensive approach are needed to better understand the biomechanical adaptations associated with CAI. The objective of this case-control study was to identify the kinematic, kinetic and EMG differences between individuals with CAI and healthy controls during walking.

Methods

Twenty-eight individuals with CAI and 26 healthy controls were recruited to walk at a self-selected speed during which lower limb kinematics, kinetics and EMG were analysed. Ankle and knee angles and moments as well as gluteus medius, vastus lateralis, gastrocnemius lateralis, peroneus longus and tibialis anterior muscles activity were compared between the CAI and control groups using one-dimensional statistical parametric mapping.

Results

The CAI group exhibited greater ankle inversion angles from 14 to 48% of the stance phase (%SP) (p = 0.008), ankle eversion moments from 40 to 78%SP (p < 0.001), knee abduction moments from 3 to 6%SP and peroneus longus muscle activity from 0 to 15%SP (p = 0.003) and 60 to 76%SP (p = 0.003) compared to the control group. No significant between-group differences in ankle sagittal and transverse angles and moments, knee angles, knee sagittal and transverse moments as well as gluteus medius, vastus lateralis, gastrocnemius lateralis and tibialis anterior muscles activity were found.

Conclusions

During the first half of the stance phase, individuals with CAI could be at more risk of sustaining recurrent LAS mostly due to greater ankle inversion angles. However, the greater ankle eversion moments and peroneus longus muscle activity during the second half of the stance phase were an efficient mechanism to correct this maladaptive gait pattern and allowed to attenuate the faulty ankle movements during the pre-swing phase.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13047-021-00476-6.

Multi-Session Influence of Two Modalities of Feedback and Their Order of Presentation on MI-BCI User Training

By performing motor-imagery tasks, for example, imagining hand movements, Motor-Imagery based Brain-Computer Interfaces (MI-BCIs) users can control digital technologies, for example, neuroprosthesis, using their brain activity only. MI-BCI users need to train, usually using a unimodal visual feedback, to produce brain activity patterns that are recognizable by the system. The literature indicates that multimodal vibrotactile and visual feedback is more effective than unimodal visual feedback, at least for short term training. However, the multi-session influence of such multimodal feedback on MI-BCI user training remained unknown, so did the influence of the order of presentation of the feedback modalities. In our experiment, 16 participants trained to control a MI-BCI during five sessions with a realistic visual feedback and five others with both a realistic visual feedback and a vibrotactile one. training benefits from a multimodal feedback, in terms of performances and self-reported mindfulness. There is also a significant influence of the order presentation of the modality. Participants who started training with a visual feedback had higher performances than those who started training with a multimodal feedback. We recommend taking into account the order of presentation for future experiments assessing the influence of several modalities of feedback.

Converging Robotic Technologies in Targeted Neural Rehabilitation: A Review of Emerging Solutions and Challenges

Recent advances in the field of neural rehabilitation, facilitated through technological innovation and improved neurophysiological knowledge of impaired motor control, have opened up new research directions. Such advances increase the relevance of existing interventions, as well as allow novel methodologies and technological synergies. New approaches attempt to partially overcome long-term disability caused by spinal cord injury, using either invasive bridging technologies or noninvasive human-machine interfaces. Muscular dystrophies benefit from electromyography and novel sensors that shed light on underlying neuromotor mechanisms in people with Duchenne. Novel wearable robotics devices are being tailored to specific patient populations, such as traumatic brain injury, stroke, and amputated individuals. In addition, developments in robot-assisted rehabilitation may enhance motor learning and generate movement repetitions by decoding the brain activity of patients during therapy. This is further facilitated by artificial intelligence algorithms coupled with faster electronics. The practical impact of integrating such technologies with neural rehabilitation treatment can be substantial. They can potentially empower nontechnically trained individuals-namely, family members and professional carers-to alter the programming of neural rehabilitation robotic setups, to actively get involved and intervene promptly at the point of care. This narrative review considers existing and emerging neural rehabilitation technologies through the perspective of replacing or restoring functions, enhancing, or improving natural neural output, as well as promoting or recruiting dormant neuroplasticity. Upon conclusion, we discuss the future directions for neural rehabilitation research, diagnosis, and treatment based on the discussed technologies and their major roadblocks. This future may eventually become possible through technological evolution and convergence of mutually beneficial technologies to create hybrid solutions.

Comparison of the effects of real-time propulsive force versus limb angle gait biofeedback on gait biomechanics

BACKGROUND

Reduced forward propulsion during gait, measured as the anterior component of the ground reaction force (AGRF), may contribute to slower walking speeds in older adults and gait dysfunction in individuals with neurological impairments. Trailing limb angle (TLA) is a clinically important gait parameter that is associated with AGRF generation. Real-time gait biofeedback can induce modifications in targeted gait parameters, with potential to modulate AGRF and TLA. However, the effects of real-time TLA biofeedback on gait biomechanics have not been studied thus far.

RESEARCH QUESTION

What are the effects of unilateral, real-time, audiovisual trailing limb angle biofeedback on gait biomechanics in able-bodied individuals?

METHODS

Ten able-bodied adults participated in one session of treadmill-based gait analyses comprising 60-second walking trials under three conditions: no biofeedback, AGRF biofeedback, and TLA biofeedback. Biofeedback was provided unilaterally to the right leg. Dependent variables included AGRF, TLA, ankle moment, and ankle power. One-way repeated measures ANOVA with post-hoc tests were conducted to determine the effect of the biofeedback conditions on gait parameters.

RESULTS

Compared to no biofeedback, both AGRF and TLA biofeedback induced significant increases in targeted leg AGRF without concomitant changes to the non-targeted leg AGRF. Targeted leg TLA was significantly larger during TLA biofeedback compared to AGRF biofeedback. Only AGRF biofeedback induced significant increases in ankle power; and only the TLA biofeedback condition induced increases in the non-targeted leg TLA.

SIGNIFICANCE

Our novel findings provide support for the feasibility and promise of TLA as a gait biofeedback target. Our study demonstrates that comparable magnitudes of feedback-induced increases in AGRF in response to AGRF and TLA biofeedback may be achieved through divergent biomechanical strategies. Further investigation is needed to uncover the effects of TLA biofeedback on gait parameters in individuals with neuro-pathologies such as spinal cord injury or stroke.

Investigating the Effect of Vibrotactile Feedback in Transfemoral Amputee With and Without Movable Ankle Joint

The loss of somatosensory feedback after transfemoral amputation imposes a serious challenge in achieving postural stability. In the recent past, weight shifting exercises with fixed ankle joint have been reported useful in boosting the limit of stability (LOS) only in the sound limb; the LOS on the prosthetic limb did not improve. A fixed ankle joint restricts movement in the anterior-posterior direction at the ankle level. Thus, it may suppress the ability to move forward LOS despite awareness of center of pressure (COP) due to vibrotactile feedback. Therefore, it could have limited the improvement in the LOS of a prosthetic limb in previous studies. This article investigates this hypothesis by evaluating the effect of vibrotactile feedback in the LOS of transfemoral amputees with fixed as well as movable ankle joints. This evaluation is done during weight shifting exercises. Firstly, we developed an in-house COP guided vibrotactile sensory feedback system. Next, we recruited five transfemoral amputees to perform a weight-shifting exercise with a) fixed ankle joint (single-axis cushion heel (SACH) foot) and b) movable ankle joint (single-axis foot). Finally, we analyzed the recorded center of pressure trajectory signals for the limit of stability. The findings of repeated measures ANOVA showed a marginally significant interaction ( [Formula: see text], [Formula: see text], [Formula: see text]) between ankle joint and feedback conditions during backward shifting in weight shifting exercise. Further analysis showed that during the backward shifting fixed ankle joint did not improve in the presence of vibrotactile feedback, while a marginally significant ( [Formula: see text]) improved LOS was observed in the movable ankle joint with feedback. The findings conclude that the vibrotactile feedback is more effective in transfemoral amputees with movable ankle joint compared with fixed ankle joint.

Exploring public attitude toward biofeedback technologies: Knowledge, preferences and personality tendencies

Background: Biofeedback is increasingly used in the clinical area and in daily health monitoring through wearable devices (e.g. smart watches). Nevertheless, it remains rather unknown. This study aimed to assess, in a sample of Italian citizens, the level of knowledge, attitudes, perceived efficacy and personality tendencies which could affect the uptake of biofeedback technologies.

Design and Methods: Participants were recruited by advertising the survey on the social networks, from March to May 2019. 160 subjects filled in an ad hoc online questionnaire assessing socio-demographic variables, clinical status, physical activity, knowledge and attitude towards biofeedback, psychological tendencies toward health.

Results: Data showed a good level of interest in biofeedback training in spite of poor knowledge about such technologies. Sport and chronic diseases were not correlated to a greater use of biofeedback. People informed about biofeedback technologies were more interested in undergoing biofeedback training and had higher scores in the Health Locus of Control. Finally, people who showed a positive perception of their own health (Health Esteem) did not rely on these technologies.

Discussion: Despite the huge spread of biofeedback technologies, our results disconfirmed the expectation that people having an active lifestyle or a disease were more familiar with biofeedback systems. The attitude toward such technologies seems to depend on individual tendencies.

Conclusions: This study suggests the importance to improve general public literacy on biofeedback technologies, tailor tools on their needs and characteristics, empower people’s sense of internal health control for promoting a valid use and a proper knowledge of biofeedback.

Segmentation of shoulder rehabilitation exercises for single and multiple inertial sensor systems

Introduction

Digital home rehabilitation systems require accurate segmentation methods to provide appropriate feedback on repetition counting and exercise technique. Current segmentation methods are not suitable for clinical use; they are not highly accurate or require multiple sensors, which creates usability problems. We propose a model for accurately segmenting inertial measurement unit data for shoulder rehabilitation exercises. This study aims to use inertial measurement unit data to train and test a machine learning segmentation model for single- and multiple-inertial measurement unit systems and to identify the optimal single-sensor location.

Methods

A focus group of specialist physiotherapists selected the exercises, which were performed by participants wearing inertial measurement units on the wrist, arm and scapula. We applied a novel machine learning based segmentation technique involving a convolutional classifier and Finite State Machine to the inertial measurement unit data. An accuracy score was calculated for each possible single- or multiple-sensor system.

Results

The wrist inertial measurement unit was chosen as the optimal single-sensor location for future system development (mean overall accuracy 0.871). Flexion and abduction based exercises mostly could be segmented with high accuracy, but scapular movement exercises had poor accuracy.

Conclusion

A wrist-worn single inertial measurement unit system can accurately segment shoulder exercise repetitions; however, accuracy varies depending on characteristics of the exercise.

Evaluating Sensory Acuity as a Marker of Balance Dysfunction After a Traumatic Brain Injury: A Psychophysical Approach

There is limited research on sensory acuity i.e., ability to perceive external perturbations via body-sway during standing in individuals with a traumatic brain injury (TBI). It is unclear whether sensory acuity diminishes after a TBI and if it is a contributing factor to balance dysfunction. The objective of this investigation is to first objectively quantify the sensory acuity in terms of perturbation perception threshold (PPT) and determine if it is related to functional outcomes of static and dynamic balance. Ten individuals with chronic TBI and 11 age-matched healthy controls (HC) performed PPT assessments at 0.33, 0.5, and 1 Hz horizontal perturbations to the base of support in the anterior-posterior direction, and a battery of functional assessments of static and dynamic balance and mobility [Berg balance scale (BBS), timed-up and go (TUG) and 5-m (5MWT) and 10-m walk test (10MWT)]. A psychophysical approach based on Single Interval Adjustment Matrix Protocol (SIAM), i.e., a yes-no task, was used to quantify the multi-sensory thresholds of perceived external perturbations to calculate PPT. A mixed-design analysis of variance (ANOVA) and post-hoc analyses were performed using independent and paired t-tests to evaluate within and between-group differences. Pearson correlation was computed to determine the relationship between the PPT and functional measures. The PPT values were significantly higher for the TBI group (0.33 Hz: 2.97 ± 1.0, 0.5 Hz: 2.39 ± 0.7, 1 Hz: 1.22 ± 0.4) compared to the HC group (0.33 Hz: 1.03 ± 0.6, 0.5 Hz: 0.89 ± 0.4, 1 Hz: 0.42 ± 0.2) for all three perturbation frequencies (p < 0.006 post Bonferroni correction). For the TBI group, the PPT for 1 Hz perturbations showed significant correlation with the functional measures of balance (BBS: r = −0.66, p = 0.037; TUG: r = 0.78, p = 0.008; 5MWT: r = 0.67, p = 0.034, 10MWT: r = 0.76, p = 0.012). These findings demonstrate that individuals with TBI have diminished sensory acuity during standing which may be linked to impaired balance function after TBI.

Design and Validation of a Lower-Limb Haptic Rehabilitation Robot

Present robots for investigating lower-limb motor control and rehabilitation focus on gait training. An alternative approach is to focus on restoring precursor abilities such as motor adaptation and volitional movement, as is common in upper-limb robotic therapy. Here we describe NOTTABIKE, a one degree-of-freedom rehabilitation robot designed to probe and promote these underlying capabilities. A recumbent exercise cycle platform is powered with a servomotor and instrumented with angular encoders, force-torque sensing pedals, and a wireless EMG system. Virtual environments ranging from spring-mass-damper systems to novel foot-to-crank mechanical laws present variants of leg-reaching and pedaling tasks that challenge perception, cognition, motion planning, and motor control systems. This paper characterizes the dynamic performance and haptic rendering accuracy of NOTTABIKE and presents an example motor adaptation task to illustrate its use. Torque and velocity mode controllers showed near unity magnitude ratio and phase loss less than 60 degrees up to 10 Hz. Spring rendering demonstrated 1% mean error in stiffness, and damper rendering performed comparably at 2.5%. Virtual mass rendering was less accurate but successful in varying perceived mass. NOTTABIKE will be used to study lower-limb motor adaptation in intact and impaired persons and to develop rehabilitation protocols that promote volitional movement recovery.

Effects of auditovisual feedback on eye-hand coordination in children with cerebral palsy

BACKGROUND

Children with spastic hemiplegic cerebral palsy have deficits in eye-hand coordination. This limits manual actions performed with the affected hand, especially fine motor skills such as grasping and manipulation. Visual-motor integration, grasping skills, and visual perception are collectively involved in eye-hand coordination.

AIMS

We investigated the effects of augmented biofeedback training on eye-hand coordination in children with spastic hemiplegic cerebral palsy.

METHODS AND PROCEDURES

Forty-five spastic hemiplegic cerebral palsy children (5-8 years old) were included. Children were assigned randomly into three equal groups. One group received traditional physical therapy to facilitate visual-motor integration and grasping skills for 3 months. The second group received augmented biofeedback training. The third group received a combination of augmented biofeedback training and traditional physical therapy. Children were evaluated with the Peabody Developmental Motor Scale (2nd edition) (PDMS-2). Treatment sessions were conducted for 60 min, three times a week, for 3 consecutive months.

OUTCOMES AND RESULTS

Children that received augmented biofeedback training alongside traditional physical therapy had significantly improved scores in the Visual-Motor Integration and grasping subtests compared to children that received only one intervention.

CONCLUSIONS AND IMPLICATIONS

Augmented biofeedback training alongside physical therapy improved eye-hand coordination in children with spastic hemiplegic cerebral palsy.

Disproportionate positive feedback facilitates sense of agency and performance for a reaching movement task with a virtual hand

This study investigated the generalized effects of positive feedback (PF) versus negative feedback (NF) during training on performance and sense of agency for a reach-to-touch task with a virtual hand. Virtual reality (VR) is increasingly employed for rehabilitation after neuromuscular traumas such as stroke and spinal cord injury. However, VR methods still need to be optimized for greater effectiveness and engagement to increase rates of clinical retention. In this study, we observed that training with disproportionate PF subsequently produced greater reaching performance (minimizing path length) and greater agency (perception of control) than with disproportionate NF. During PF training, there was also progressive increase in agency, but conversely a decrease in performance. Thus, the increase in performance after training may not be due to positively bolstered learning, but rather priming higher confidence reflected in greater agency. Agency was positively measured as compression in perceived time-intervals between the action of touch to a sound consequence, as standard with intentional binding paradigms. Positive feedback desirably increased agency (~180 msec) and reduced path length (1.8 cm) compared to negative feedback, which itself showed insignificant, or neutral, effects. Future investigations into optimizing virtual reality paradigms for neuromotor rehabilitation should consider agency as a driving factor for performance. These studies may serve to optimize how feedback is better presented with performance results for complex motor learning. Investigators should also ponder how personal characteristics, both cognitive and physical, may further affect sensitivity to feedback and the rate of neuromotor rehabilitation.

Effect of augmented biofeedback for improvement of range of motion and upper extremity functionality in obstetric brachial plexus injury: a randomised control trial

Background/Aims

The loss of mobility and functional activities of the upper limb are the main longstanding complications of obstetric brachial plexus injury. The aim of this study was to investigate the effect of the augmented biofeedback system in conjunction with traditional physical therapy on the range of motion and functional activities in children with obstetric brachial plexus injury.

Methods

A total of 45 children aged from 6 to 10 years with obstetric brachial plexus injury were assigned into two groups. The control group received a traditional physical therapy programme, and the study group received the same programme with augmented biofeedback for 6 weeks. The main outcome parameters were the upper limb active range of motion, Mallet scale and Active Movement scale.

Results

The children in the study group showed greater significant improvement in all measured parameters compared with those in the control group.

Conclusions

Adding augmented biofeedback to the physical therapy programme provided greater improvement in upper limb mobility and functional activities for children with obstetric brachial plexus injury children.

The effect of short foot exercise using visual feedback on the balance and accuracy of knee joint movement in subjects with flexible flatfoot

BACKGROUND

Flexible flatfoot is a condition characterized by the deformations of the foot where the calcaneus is pronated by weight support. Flat feet can affect balance and the entire chain of motion, causing indirect problems in adjacent joints. We investigated the effects of short foot exercise (SFE) using visual feedback on the static balance and function of proximal joints in subjects with flexible flat feet.

METHOD AND ANALYSIS

This study involved 30 participants who were assigned to either of the 2 groups: the flexible flatfoot group (n = 15, 8 men and 7 women, aged 22.00 ± 2.07 years) and normal foot group (n = 15, 7 men and 8 women, aged 22.13 ± 1.55 years). All subjects performed the SFE with visual feedback. SFE programs were performed 20 minutes a day, 5 times a week, for a total of 5 weeks. The static balance and accuracy of knee joint motions were compared before and after training.

RESULTS

There was a significant difference in static balance pre- and post-exercise in the flatfoot group but not in the normal foot group. Moreover, in the flatfoot group, the accuracy of knee joint motions was significantly different between pre- and post-exercise in the closed chain but not in the open chain.

CONCLUSION

This study examined the influence of SFE using visual feedback on the balance and accuracy of knee joint movements in subjects with flatfoot and demonstrated that this exercise, using visual feedback, improved the balance and accuracy of knee movement.

Increase in Muscle Activation during Physiotherapy with Electromyography Biofeedback for Patients with Acute Cervical Spinal Cord Injuries

Surface electromyography (sEMG) can be used as a biofeedback (BFB) parameter to provide information to participants regarding muscle activation in a variety of settings. The objective of our study is to assess whether an sEMG BFB display during physical therapy sessions for acute spinal cord injured inpatients would assist in increasing muscle use and patient engagement during therapy. In addition, we sought to assess whether the therapist and patients would find the sEMG BFB relevant and useful. To achieve this objective, we examined the effect of visual sEMG BFB system in improving muscle activation and therapeutic outcomes during experimental sessions that mimicked conventional slings therapy sessions with a research therapist providing the therapy. We recruited two inpatients with recent spinal cord injuries (SCI) that had been prescribed (clinical) slings therapy as part of their clinical standard of care at our acute rehabilitation hospital. During each experimental session there were two portions. One was the control period which required the participants to repeat elbow flexion 10 times under conventional clinical slings therapy protocols. The other was the BFB period, where the therapist guided the participant in the same movement but both therapist and the participant were provided with visual feedback of real-time sEMG signals recorded from participant's biceps brachii muscles. Our preliminary results show that both participants demonstrated statistically significant improvement of muscle activation level with the sEMG BFB system compared with conventional clinical slings therapy protocols.

Augmented Biofeedback Training with Physical Therapy Improves Visual-Motor Integration, Visual Perception, and Motor Coordination in Children with Spastic Hemiplegic Cerebral Palsy: A Randomised Control Trial

Aim: The aim of this study is to investigate the efficacy of combining augmented biofeedback training and standard therapy for improving visual-motor integration (VMI), visual perception (VP), and motor coordination (MC) in children with spastic cerebral palsy (CP).Methods: Participants were 45 children, 5-8 years of age, with spastic hemiplegic CP. They were randomized into three groups: group A followed a 3-month specially designed program physical therapy intervention to facilitate VMI and VP. Group B received augmented biofeedback training. Group C received augmented biofeedback training and the physical therapy program provided to group A. The treatment sessions lasted 60 min, three times a week for three months. The Beery-Buktenica Developmental Test of VMI and its supplemental tests were used to evaluate the children before and after the program.Results: After a 3-month treatment, standard scores and age equivalent scores for VMI, VP, and MC were significantly higher in group C compared with group A.Conclusion: The combination of augmented biofeedback and physical therapy could be used to improve VMI, VP, and MC in children with spastic hemiplegic CP.

Motor Improvement in Adolescents Affected by Ataxia Secondary to Acquired Brain Injury: A Pilot Study

Aim

To assess changes in locomotion and balance in adolescents affected by ataxia secondary to acquired brain injury after a rehabilitation treatment with physiotherapy and the Gait Real-time Analysis Interactive Lab (GRAIL), an immersive virtual reality platform.

Methods

11 ataxic adolescents (16(5) years old, 4.7(6.7) years from injury) underwent 20 45-minute sessions with GRAIL plus 20 45-minute sessions of physiotherapy in one month. Patients were assessed before and after rehabilitation with functional scales and three-dimensional multiple-step gait analysis.

Results

Results showed significant improvements in ataxia score assessed by the Scale for the Assessment and Rating of Ataxia, in dimension D and E of Gross Motor Function Measure, in walking endurance and in balance abilities. Moreover, the training fostered significant changes at hip, knee, and ankle joints, and the decrease of gait variability, toward healthy references.

Interpretation

In spite of the pilot nature of the study, data suggest that training with immersive virtual reality and physiotherapy is a promising approach for ataxic gait rehabilitation, even in chronic conditions.

Feedback Design in Targeted Exercise Digital Biofeedback Systems for Home Rehabilitation: A Scoping Review

Digital biofeedback systems (DBSs) are used in physical rehabilitation to improve outcomes by engaging and educating patients and have the potential to support patients while doing targeted exercises during home rehabilitation. The components of feedback (mode, content, frequency and timing) can influence motor learning and engagement in various ways. The feedback design used in DBSs for targeted exercise home rehabilitation, as well as the evidence underpinning the feedback and how it is evaluated, is not clearly known. To explore these concepts, we conducted a scoping review where an electronic search of PUBMED, PEDro and ACM digital libraries was conducted from January 2000 to July 2019. The main inclusion criteria included DBSs for targeted exercises, in a home rehabilitation setting, which have been tested on a clinical population. Nineteen papers were reviewed, detailing thirteen different DBSs. Feedback was mainly visual, concurrent and descriptive, frequently providing knowledge of results. Three systems provided clear rationale for the use of feedback. Four studies conducted specific evaluations of the feedback, and seven studies evaluated feedback in a less detailed or indirect manner. Future studies should describe in detail the feedback design in DBSs and consider a robust evaluation of the feedback element of the intervention to determine its efficacy.

Principles of Neurorehabilitation After Stroke Based on Motor Learning and Brain Plasticity Mechanisms

What are the principles underlying effective neurorehabilitation? The aim of neurorehabilitation is to exploit interventions based on human and animal studies about learning and adaptation, as well as to show that the activation of experience-dependent neuronal plasticity augments functional recovery after stroke. Instead of teaching compensatory strategies that do not reduce impairment but allow the patient to return home as soon as possible, functional recovery might be more sustainable as it ensures a long-term reduction in impairment and an improvement in quality of life. At the same time, neurorehabilitation permits the scientific community to collect valuable data, which allows inferring about the principles of brain organization. Hence neuroscience sheds light on the mechanisms of learning new functions or relearning lost ones. However, current rehabilitation methods lack the exact operationalization of evidence gained from skill learning literature, leading to an urgent need to bridge motor learning theory and present clinical work in order to identify a set of ingredients and practical applications that could guide future interventions. This work aims to unify the neuroscientific literature relevant to the recovery process and rehabilitation practice in order to provide a synthesis of the principles that constitute an effective neurorehabilitation approach. Previous attempts to achieve this goal either focused on a subset of principles or did not link clinical application to the principles of motor learning and recovery. We identified 15 principles of motor learning based on existing literature: massed practice, spaced practice, dosage, task-specific practice, goal-oriented practice, variable practice, increasing difficulty, multisensory stimulation, rhythmic cueing, explicit feedback/knowledge of results, implicit feedback/knowledge of performance, modulate effector selection, action observation/embodied practice, motor imagery, and social interaction. We comment on trials that successfully implemented these principles and report evidence from experiments with healthy individuals as well as clinical work.

A multimodal training with visual biofeedback in subacute stroke survivors: a randomized controlled trial

BACKGROUND

Early interventions maximizing patient's involvement are essential to promote gait restoration and motor recovery after stroke.

AIM

The aim of this study is to evaluate the effects of a multimodal biofeedback training involving cycling augmented by functional electrical stimulation (FES) and balance exercises on walking ability and motor recovery.

DESIGN

Randomized controlled trial (NCT02439515).

SETTING

Inpatient rehabilitation facility.

POPULATION

Subacute stroke survivors (less than 6 months from the first event) aged up to 90 years old.

METHODS

Sixty-eight participants were randomly allocated to an experimental group, performing 15 sessions of biofeedback FES-cycling training followed by 15 sessions of biofeedback balance training (20 minutes each) in addition to usual care (70 minutes), and a control group performing 30 sessions (90 minutes) of usual care. Participants were evaluated before training, after 15 sessions, after 30 sessions, and at 6-month follow-up through: gait speed (primary outcome), spatiotemporal gait parameters, Six-Minute Walking Test, Functional Independence Measure, Motricity Index, Trunk Control Test, Berg Balance Scale, and Fall Efficacy Scale.

RESULTS

Both groups significantly improved over time, but no group and interaction effects were found for any outcomes. The 73% of the experimental group achieved a clinically meaningful change in gait speed compared to the 38% of the control group (P=0.048). These percentages were even more unbalanced for patients with a moderate to severe gait impairment at baseline (91% versus 36%; P=0.008).

CONCLUSIONS

The multimodal biofeedback training was not statistically superior to usual care, showing only a positive trend in favor of the experimental group on locomotion recovery. Patients initially not able to walk might be the best candidates for such a training.

CLINICAL REHABILITATION IMPACT

The multimodal biofeedback training is a task-specific, repetitive and intensive training requiring a minimal supervision, which might result in a lower staff to patient ratio if organized in group sessions. Therefore, it can represent a good alternative for early stroke rehabilitation.