Improved stability of long-duration sitting in spatial neglect after a single session of prism adaptation.

Spatial neglect after right brain stroke affects balance, and improvements in sitting balance after prism adaptation have been demonstrated using short-duration center of pressure (CoP) data. We present long-duration (5 min) CoP and trunk muscles electromyography recordings of a 61-year-old man with left-sided spatial neglect, before and after a single session of prism adaptation. His CoP-derived measures showed improved balance and postural stability in both the anterior-posterior and medial-lateral directions after prism adaptation. Concurrently, asymmetry in neuromuscular activations was reduced. The findings suggest that improved sitting balance may be associated with more symmetrical activation of trunk muscles after prism adaptation.

Cyclogram based Joint Symmetry Assessment after Utilization of a Foot Drop Stimulator during Post Stroke Hemiplegic Gait.

In the absence of standardized symmetry assessments, quantifying symmetry based on the kinematic evolution of lower extremity joints can elucidate gait irregularities. The objective was to develop a novel cyclogram based symmetry (CBS) method to quantify lower extremity joints' symmetry and assess the effect of 6-month utilization of foot drop stimulator (FDS) on CBS of the lower limbs during hemiplegic gait post stroke. Twenty-four participants (13 stroke and 11 healthy controls (HC)) performed 10 walking trials at a free cadence on level ground. Symmetry values were computed using geometric properties of bilateral cyclograms obtained from normalized sagittal ankle, knee and hip kinematics. CBS and traditional temporospatial symmetry values were compared between the two groups using independent sample t-test. Effect of FDS utilization on symmetry was assessed by paired sample t- test computed at baseline and 6-month follow up. The CBS method successfully showed that the HC group was significantly more symmetrical at the ankle (p=0.001), knee (p=0.001) and hip (p<0.005) compared with the stroke group. The stroke group showed significant increment in hip symmetry with FDS at baseline but did not show any significant CBS changes at follow up. Pearson correlations revealed that hip and knee CBS had a significant influence on overall walking speed. The CBS method presents a unique approach to calculate symmetry based on the kinematics of lower extremities during gait.

Relationship between Timed Up and Go performance and quantitative biomechanical measures of balance.

Traumatic brain injury (TBI) impairs sensory-motor functions, with debilitating consequences on postural control and balance, which persist during the chronic stages of recovery. The Timed Up and Go (TUG) test is a reliable, safe, time-efficient, and one of the most widely used clinical measures to assess gait, balance, and fall risk in TBI patients and is extensively used in inpatient and outpatient settings. Although the TUG test has been used extensively due to its ease of performance and excellent reliability, limited research has been published that investigates the relationship between TUG performance and quantitative biomechanical measures of balance. The objective of this paper was to quantify the relationship between biomechanical variables of balance and the TUG scores in individuals with chronic TBI. Regression models were constructed using six biomechanical variables to predict TUG scores. The model that conservatively removed gait speed (i.e., TUG-1/GS) gave the best results, achieving a root-mean-square error of ∼±2 s and explaining over 69% of the variability.

Enhancing Anticipatory and Compensatory Postural Responses to Improve Balance in Individuals with TBI.

Traumatic Brain Injury (TBI) is one of the leading causes of sensorimotor deficits in adults and often results in balance impairments. Two types of postural mechanisms are employed to achieve balance during perturbations: Anticipatory Postural Adjustments (APA) and Compensatory Postural Adjustments (CPA). People with TBI have reduced APA/CPA responses due to sensory-motor deficits from the injury. The objective of this feasibility study was to evaluate a Perturbation-based Balance Training program with visual cues (PBTvc) to target both APA/CPA responses to improve balance. The evaluation included biomechanical (reactive balance during random perturbation) and functional (Berg Balance Scale, Timed Up and Go and Falls Efficacy Scale) metrics. Preliminary data is presented for two participants with chronic TBI who received 16 sessions of PBTvc. The results show an improved range of trunk oscillation and time to stability during random perturbation tasks with corresponding improvements in Berg Balance Scale, Timed Up & Go, and Falls Efficacy Scale. The results suggest that PBTvc has the potential to improve APA/CPA mechanisms for functional recovery.Clinical Relevance- Preliminary data provides initial evidence for PBTvc as a therapeutic intervention for balance rehabilitation in adults with TBI.

40 years of actigraphy in sleep medicine and current state of the art algorithms.

For the last 40 years, actigraphy or wearable accelerometry has provided an objective, low-burden and ecologically valid approach to assess real-world sleep and circadian patterns, contributing valuable data to epidemiological and clinical insights on sleep and sleep disorders. The proper use of wearable technology in sleep research requires validated algorithms that can derive sleep outcomes from the sensor data. Since the publication of the first automated scoring algorithm by Webster in 1982, a variety of sleep algorithms have been developed and contributed to sleep research, including many recent ones that leverage machine learning and / or deep learning approaches. However, it remains unclear how these algorithms compare to each other on the same data set and if these modern data science approaches improve the analytical validity of sleep outcomes based on wrist-worn acceleration data. This work provides a systematic evaluation across 8 state-of-the-art sleep algorithms on a common sleep data set with polysomnography (PSG) as ground truth. Despite the inclusion of recently published complex algorithms, simple regression-based and heuristic algorithms demonstrated slightly superior performance in sleep-wake classification and sleep outcome estimation. The performance of complex machine learning and deep learning models seem to suffer from poor generalization. This independent and systematic analytical validation of sleep algorithms provides key evidence on the use of wearable digital health technologies for sleep research and care.

A Novel Core Strengthening Intervention for Improving Trunk Function, Balance and Mobility after Stroke.

This paper a novel core-strengthening intervention (CSI) delivered using the AllCore360°, a device that targets trunk muscles through a systematic, high-intensity rotating-plank exercise. Three individuals (age: 61.7 ± 3.2 years; range: 58-64 years) with post-stroke hemiplegia participated in 12-sessions of the CSI. The participants completed up to 142 rotating planks at inclination angles (IAs) that ranged from 40° to 65°, over 12 sessions. The interventional effects on the functional outcomes of trunk performance, balance and mobility were assessed using the Trunk Impairment Scale (TIS), the Berg Balance Scale (BBS), the Timed-Up and Go (TUG) test, the 10-m walk test (10MWT), and the 6-min walk test (6MWT). Postural outcomes were assessed using the center of pressure (CoP) data recorded during quiet standing on a balance platform, and neuromuscular outcomes were assessed using electromyography (EMG) during AllCore360° rotations. All participants completed the CSI (minimum of 120 rotations), demonstrating the feasibility of the CSI in chronic stroke. The CoP data suggested improved lateral control of posture during standing across participants (averaging an over 30% reduction in lateral sway), while the EMG data revealed the ability of the CSI to systematically modulate trunk muscle responses. In summary, the current investigation presents the feasibility of a novel delivery method for core strengthening to maximize rehabilitation outcomes in the chronic phase of stroke.

Wearable devices for tracking physical activity in the community after an acquired brain injury: A systematic review.

OBJECTIVE: The application of wearable devices in individuals with acquired brain injury (ABI) resulting from stroke or traumatic brain injury (TBI) for monitoring physical activity (PA) has been relatively recent. The current systematic review aims to provide insights into the adaption of these devices, the outcome metrics, and their transition from the laboratory to the community for PA monitoring of individuals with ABI. LITERATURE SURVEY: The PubMed and Google Scholar databases were systematically reviewed using appropriate search terms. A total of 20 articles were reviewed from the last 15 years. METHODOLOGY: Articles were classified into three categories: PA measurement studies, PA classification studies, and validation studies. The quality of studies was assessed using a quality appraisal checklist. SYNTHESIS: It was found that the transition of wearable devices from in-lab to community-based studies in individuals with stroke has started but is not widespread. The transition of wearable devices in the community has not yet started for individuals with TBI. Accelerometer-based devices were more frequently chosen than pedometers and inertial measurement units. No consensus on a preferred wearable device (make or model) or wear location could be identified, although step count was the most common outcome metric. The accuracy and validity of most outcome metrics used in the community were not reported for many studies. CONCLUSIONS: To facilitate future studies using wearable devices for PA measurement in the community, we recommend that researchers provide details on the accuracy and validity of the outcome metrics specific to the study environment. Once the accuracy and validity are established for a specific population, wearable devices and their derived outcomes can provide objective information on mobility impairment as well as the effect of rehabilitation in the community.

Effects of Computerized Biofeedback-based Balance Intervention on the Muscle Coactivation Patterns during Dynamic Postural Control in Traumatic Brain Injury.

Balance Dysfunction (BDF) is a severe conse-quence of Traumatic Brain Injury (TBI) that significantly increases the falls risk. However, the neuromuscular mecha-nisms of the BDF are not adequately researched. Therefore, in this study, our objective was to investigate the effects of a Computerized Biofeedback-based Balance Intervention (CBBI) on the muscle coactivation patterns in a group of TBI participants. This study presents the findings from 13 TBI individuals randomized into the Intervention group (TBI - INT, N=6) and Control group (TBI-CTL, N=7). Using a computerized posturography platform (Neurocom Balance Master) during baseline and follow-up assessment visits, the participant's pos-tural response to anterior-posterior balance perturbations were recorded in a multimodal setup including electroencephalogra-phy (EEG), electromyography (EMG), and the platform sway in terms of center of pressure (COP). The muscle responses were recorded from lower-limb muscles, including tibialis an-terior (TA) and gastrocnemius (GAST), whose coactivation was computed using a metric called Co-Contraction Index (CCI). Clinical outcome measures such as Berg Balance Scale (BBS), 10 Meter Walk Test (10MWT), and Timed Up-and-Go (TUG) tests were used to evaluate functional balance and mobility. The comparison of CCI values across time points (baseline and follow-up) revealed a significant decrease (p<0.01) in the TBI-INT group but not TBI-CTL. The intervention-related changes in CCI correlated with the changes in BBS score (from baseline to follow-up). These preliminary findings demonstrate that the CBBI training may help postural stability by facilitating the coactivation between muscles involved in postural control. Clinical relevance- The current knowledge of changes in the neuromuscular response to balance perturbation in TBI is limited. Our study opens the possibility of using the muscle CCI metric to evaluate the muscle response in individuals with impaired balance.

Spinal Cord Transcutaneous Stimulation Enables Volitional Knee Extension in Motor-complete SCI.

Non-invasive spinal cord transcutaneous stimulation (scTS) is often applied to one or multiple spinal segments and may improve motor control after spinal cord injury (SCI). The purpose of this pilot study was to apply tonic scTS to an individual with motor-complete spinal cord injury (SCI) in order to initiate and maintain volitional control during a specific lower-extremity motor task. The participant's legs were placed in a gravity-neutral position, and he was asked to extend his knee, with and without the presence of tonic scTS. Our results show intentional voluntary control of knee extension with scTS (with no assistance). Our preliminary findings highlight how scTS neuromodulation of the spinal circuitry has the potential to restore motor function for people with motor-complete SCI. Clinical Relevance- This investigation is critical to better understand the neuromodulatory effects of tonic scTS for augmentation of voluntary-induced muscle activations in individuals with motor-complete SCI.

Objective evaluation of the risk of falls in individuals with traumatic brain injury: feasibility and preliminary validation.

Falls are a significant health concern for individuals with traumatic brain injury (TBI). For developing effective preemptive strategies to reduce falls, it is essential to get an accurate and objective assessment of fall-risk. The current investigation evaluates the feasibility of a robotic, posturography-based fall-risk assessment to objectively quantify the risk of falls in individuals with TBI. Five individuals with chronic TBI (age: 56.2 ± 4.7 years, time since injury: 13.09±11.95 years) performed the fall-risk assessment on hunova- a commercial robotic platform for assessing and training balance. The unique assessment considers multifaceted fall-driving components, including static and dynamic balance, sit-to-stand, limits of stability, responses to perturbations, gait speed, and history of previous falls and provides a composite score for risk of falls, called silver index (SI), a number between 0 (no risk) and 100 (high risk) based on a machine learning-based predictive model. The SI score for individuals with TBI was 66±32.1 (min: 32, max: 100) - categorized as medium-to-high risk of falls. The construct validity of SI outcome was performed by evaluating its relationship with clinical outcomes of functional balance and mobility (Berg Balance Scale (BBS), Timed-Up and Go (TUG), and gait speed) as well as posturography outcomes (Center of Pressure (CoP) area and velocity). The bivariate Pearson correlation coefficient, although not statistically significant, suggested the presence of linear relationships (0.52 > r > 0.84) between SI and functional and posturography outcomes, supporting the construct validity of SI. A large sample is needed to further prove the validity of the SI outcome before it is used for meaningful interpretations of the risk of falls in individuals with TBI.Clinical Relevance- Clinical assessments of risk of falls are traditionally based on questionnaires that may lack objectivity, consistency, and accuracy. The current work tests the feasibility of using a robotic platform-based assessment to objectively quantify the risk of falls in individuals with TBI.

A Novel Core-Strengthening Program for Improving Trunk Function, Balance and Mobility after Stroke: a Case Study.

The objective of the current investigation was to evaluate the feasibility of a core-strengthening program delivered to a chronic stroke participant using a novel robotic device, AllCore360°, which targets trunk muscles through a systematic, consistent, high-intensity exercise. A 58-year old male with hemiplegia post stroke (time since injury: 18 years) was enrolled and performed 12-sessions of the core-strengthening program on AllCore360°. The participant completed a total of 142 360°-rotating-planks (called as 'spins') at four inclination angles, over 12 sessions. Assessments at baseline and follow up included posturography during quiet standing, electromyography (EMG) during AllCore360° spins, and assessments for trunk function (Trunk Impairment Scale (TIS)), balance (Berg Balance Scale (BBS) and mobility (Timed-Up and Go (TUG), 10-meter Walk test (10MWT), 6-minute Walk Test (6MWT)). Clinically meaningful improvements were observed in the TIS (73%), the BBS (45.2%), and the TUG test (22.7%). Medial-lateral Center of Pressure (MLCoP) data showed reduced RMS and range by 32.3% and 29.2%, respectively. EMG data from left and right rectus abdominis (RAB) muscles showed increased levels of activations for both inclination angles, 65° (LRAB: 74%, RRAB: 48.4%) and 55° (LRAB: 22.3%, RRAB: 28.7%). The participant rated the core-strengthening program 71 (scale: 0-126) on Physical ACtivity Enjoyment Scale at the follow up, showing a high level of satisfaction and engagement toward the training program. The preliminary results suggest that the novel robotic design and enhanced engagement of neuromuscular mechanisms features of AllCore360° core-strengthening program could facilitate improvements in trunk function, balance and mobility post stroke. A study with a large sample and an appropriate control group needs to be performed in the future.Clinical Relevance- The majority of clinical programs include core-stability exercises for improving trunk function. The current investigation presents a novel robotic-device based core-strengthening program that can provide systematic, consistent, and repetitive practice for optimal functional gains.

Balance Control Strategies during Perturbed Standing after a Traumatic Brain Injury: Kinematic Analysis.

The objective of the current investigation was to examine the presence, absence or alteration of fundamental postural control strategies in individuals post traumatic brain injury (TBI) in response to base of support perturbations in the anterior-posterior (AP) direction. Four age-matched healthy controls (age: 46.50 ± 5.45 years) and four individuals diagnosed with TBI (age: 48.50 ± 9.47 years, time since injury: 6.02 ± 4.47 years) performed standing on instrumented balance platform with integrated force plates while 3D motion capture data was collected at 60 Hz. The platform was programmed to move in the AP direction, during a sequence of 5 perturbations delivered in a sinusoidal pattern at a frequency of 1 Hz, with decreasing amplitudes of 10, 8, 6, 4, and 2 mm respectively. The sagittal plane peak-to-peak range and root mean square (RMS) of the hip, knee, and ankle joint angles during the 5 seconds of perturbation were computed from optical motion capture data. The TBI group had a higher mean range (5.17 ± 1.91°) about the ankle compared to the HC group (4.17 ± 0.81°) for the 10mm perturbation, but their mean range was smaller than the HCs for the other 4 conditions. About the hip, the TBI group's mean range was larger than the HC's for all conditions. For both groups, the mean range decreased with perturbation amplitude for all conditions. The TBI group showed larger changes in mean range and RMS values as the amplitude of the perturbation changed, while the HC group showed smaller intertrial changes. The results suggest that the TBI group was substantially more reliant on the hip strategy to maintain balance during the perturbations and this reliance was well linked with perturbation amplitude.Clinical Relevance- Existing information regarding changes in postural control strategies in individuals post TBI is limited. The current work demonstrates lower limb kinematic differences between HC and TBI and some preliminary evidence on increased hip movement in the TBI group.

Accuracy comparison of machine learning algorithms at various wear-locations for activity identification post stroke: A pilot analysis.

Objective and accurate activity identification of physical activities in everyday life is an important aspect in assessing the impact of various post-stroke rehabilitation therapies and interventions. Since post-stroke hemiparesis affects gait and balance in individuals with stroke, activity identification algorithms that consider stroke-specific movement irregularities are needed. While wearable physical activity monitors provide the means to detect activities in the free-living, algorithms using their data are specific to the wear location of the device. This pilot study builds, validates, and compares three machine learning algorithms (linear support vector machine, Random Forest, and RUSBoosted trees) at three popular wear locations (wrist, waist, and ankle) to identify and accurately distinguish mobility-related activities (sitting, standing and walking) in individuals with chronic stroke. A total of 102 minutes of data from two lab visits of three-stroke participants was used to build the classifiers. A 5-fold cross-validation technique was used to validate and compare the accuracy of classifiers. RUSBoosted trees using data from waist and ankle activity monitors, with an accuracy of 99.1%, outperformed other classifiers in detecting three activities of interest.Clinical Relevance- One of the major aims of post-stroke rehabilitation is improving mobility, which may be facilitated by understanding the structure and pattern of everyday mobility through real-world, objective outcomes. Accurate activity identification, as shown in this pilot investigation, is an essential first step before developing objective outcomes for monitoring mobility and balance in everyday life of these individuals.

Enhancing sensory acuity and balance function using near-sensory biofeedback-based perturbation intervention for individuals with traumatic brain injury.

BACGROUND: Interventions addressing balance dysfunction after traumatic brain injury (TBI) only target compensatory aspects and do not investigate perceptual mechanisms such as sensory acuity. OBJECTIVE: To evaluate the efficacy of a novel intervention that integrates sensory acuity with a perturbation-based approach for improving the perception and functional balance after TBI. METHODS: A two-group design was implemented to evaluate the effect of a novel, perturbation-based balance intervention. The intervention group (n = 5) performed the intervention with the sinusoidal (0.33, 0.5, and 1 Hz) perturbations to the base of support with amplitudes derived using our novel outcome of sensory acuity - perturbation perception threshold (PPT). The efficacy is evaluated using changes in PPT and functional outcomes (Berg Balance Scale (BBS), Timed-up and Go (TUG), 5-meter walk test (5MWT), and 10-meter walk test (10MWT)). RESULTS: There was a significant post-intervention change in PPT for 0.33 Hz (p = 0.021). Additionally, clinically and statistically significant improvements in TUG (p = 0.03), 5MWT (p = 0.05), and 10MWT (p = 0.04) were observed. CONCLUSIONS: This study provides preliminary efficacy of a novel, near-sensory balance intervention for individuals with TBI. The use of PPT is suggested for a comprehensive understanding and treatment of balance dysfunction. The promising results support the investigation in a larger cohort.

Isolating Transcutaneous Spinal Cord Stimulation Artifact to Identify Motor Response during Walking.

The objective of this investigation was to demonstrate the applicability of a custom-developed EMD-Notch filtering algorithm to isolate the scTS-induced artifact from sEMG signals during walking in an individual with motor-incomplete SCI. Overall, the EMD-Notch filtering algorithm provides an effective approach to isolate the scTS artifact, extract the sEMG data, and further study the modulation of the spinal neuronal networks during dynamic activities.Clinical Relevance- This investigation will help with the modification of individualized scTS parameters to achieve task-specific neuromodulatory effects.

Augmented-reality guided treadmill training as a modality to improve functional mobility post-stroke: A proof-of-concept case series.

Objective: To provide a proof-of-concept for a novel stroke-gait-specific augmented reality (AR)-guided treadmill intervention by evaluating its effect on temporospatial and functional outcomes of mobility.Methods: Two females with hemiplegia post stroke were recruited for participation in a 4-week intervention, and a single healthy control was recruited for baseline comparisons. The stroke-intervention (SI) participant (aged 54-years), completed 12 sessions of AR-guided treadmill intervention. The stroke-control (SC) participant (aged 59-years) completed 12 sessions of conventional treadmill intervention. Temporospatial and functional mobility were assessed pre-intervention, post-intervention, and at 1-month follow-up. Physical ACtivity Enjoyment Scale (PACES) was administered post-intervention.Results: The SI participant showed clinically meaningful improvements in functional outcomes post-intervention and at 1-month follow-up (Berg balance score (BBS): +6 and +10 points; Dynamic Gait Index (DGI): +2 at post-intervention only; walking speed: +0.19 and +0.24 m/s; 6-minute walk test (6MWT): +51.9 and +38.9) respectively. The SC showed clinically meaningful improvements in BBS (+3 and +3) and walking speed (+0.06 at post-intervention). The PACES scores showed that the SI participant had a significantly higher (23 points) enjoyment level during the intervention compared to the SC participant. The SI participant was more asymmetric compared to the SC participant at pre and post-intervention visits.Conclusions: The SI participant showed greater improvement in functional assessments compared to the SC participant post intervention. The AR-guided approach may have added benefits compared to traditional treadmill training, while providing better customization, patient enjoyment, and engagement. Further investigation with a larger sample is warranted.

Categorizing and comparing psychophysical detection strategies based on biomechanical responses to short postural perturbations.

BACKGROUND: A fundamental unsolved problem in psychophysical detection experiments is in discriminating guesses from the correct responses. This paper proposes a coherent solution to this problem by presenting a novel classification method that compares biomechanical and psychological responses. METHODS: Subjects (13) stood on a platform that was translated anteriorly 16 mm to find psychophysical detection thresholds through a Adaptive 2-Alternative-Forced-Choice (2AFC) task repeated over 30 separate sequential trials. Anterior-posterior center-of-pressure (APCoP) changes (i.e., the biomechanical response R(B)) were analyzed to determine whether sufficient biomechanical information was available to support a subject's psychophysical selection (R(Ψ)) of interval 1 or 2 as the stimulus interval. A time-series-bitmap approach was used to identify anomalies in interval 1 (a1) and interval 2 (a2) that were present in the resultant APCoP signal. If a1 > a2 then R(B) = Interval 1. If a1 < a2, then R(B)= Interval 2. If a2-a1 < 0.1, R(B) was set to 0 (no significant difference present in the anomaly scores of interval 1 and 2). RESULTS: By considering both biomechanical (R(B)) and psychophysical (R(Ψ)) responses, each trial run could be classified as a: 1) HIT (and True Negative), if R(B) and R(Ψ) both matched the stimulus interval (SI); 2) MISS, if R(B) matched SI but the subject's reported response did not; 3) PSUEDO HIT, if the subject signalled the correct SI, but R(B) was linked to the non-SI; 4) FALSE POSITIVE, if R(B) = R(Ψ), and both associated to non-SI; and 5) GUESS, if R(B) = 0, if insufficient APCoP differences existed to distinguish SI. Ensemble averaging the data for each of the above categories amplified the anomalous behavior of the APCoP response. CONCLUSIONS: The major contributions of this novel classification scheme were to define and verify by logistic models a 'GUESS' category in these psychophysical threshold detection experiments, and to add an additional descriptor, "PSEUDO HIT". This improved classification methodology potentially could be applied to psychophysical detection experiments of other sensory modalities.

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.

Use of Surface EMG in Clinical Rehabilitation of Individuals With SCI: Barriers and Future Considerations.

Surface electromyography (sEMG) is a widely used technology in rehabilitation research and provides quantifiable information on the myoelectric output of a muscle. In this perspective, we discuss the barriers which have restricted the wide-spread use of sEMG in clinical rehabilitation of individuals with spinal cord injury (SCI). One of the major obstacles is integrating the time-consuming aspects of sEMG in the already demanding schedule of physical therapists, occupational therapists, and other clinicians. From the clinicians' perspective, the lack of confidence to use sEMG technology is also apparent due to their limited exposure to the sEMG technology and possibly limited mathematical foundation through educational and professional curricula. Several technical challenges include the limited technology-transfer of ever-evolving knowledge from sEMG research into the off-the-shelf EMG systems, lack of demand from the clinicians for systems with advanced features, lack of user-friendly intuitive interfaces, and the need for a multidisciplinary approach for accurate handling and interpretation of data. We also discuss the challenges in the application and interpretation of sEMG that are specific to SCI, which are characterized by non-standardized approaches in recording and interpretation of EMGs due to the physiological and structural state of the spinal cord. Addressing the current barriers will require a collaborative, interdisciplinary, and unified approach. The most relevant steps could include enhancing user-experience for students pursuing clinical education through revised curricula through sEMG-based case studies/projects, hands-on involvement in the research, and formation of a common platform for clinicians and technicians for self-education and knowledge share.

Anticipatory and Compensatory Postural Responses during Perturbed Standing in Individuals with Traumatic Brain Injury.

Anticipatory postural adjustments (APA) and compensatory postural adjustments (CPA) are neuromuscular responses generated to stabilize the body and achieve balance during perturbations. The impaired sensory integration after a traumatic brain injury (TBI) can limit the ability to perceive perturbations and potentially affect the ability to generate APA and CPA responses. The main objective of this investigation is to explore the existence of APA and CPA generation in tibialis anterior (TA) and gastrocnemius (GAST) muscles during base of support perturbations in healthy controls (HC) as well as individuals with TBI. The secondary objective is to explore the effectiveness of a novel computerized biofeedback based intervention (CBBI) at improving APA and CPA responses in individuals with TBI. We observed that all three groups - HC (n=5), TBI-control (n=5), and TBI-Intervention (n=4) showed the presence of only CPA responses for the TA muscle, however, these responses were longer and variable for both TBI groups, compared to the short and consistent responses of the HC group. The GAST was involved in both APA and CPA for all groups. After the 4-week CBBI period, the TBI-I group showed increased APA responses for both TA and GAST. Further, the TBI-I group showed reduced CPA responses for both TA and GAST after the intervention. The elevated and longer CPA responses of TA and GAST and lower APA responses of GAST could suggest impaired postural control. Due to their significance and potential link to the balance dysfunction, these mechanisms need to be studied comprehensively in larger samples in order to effectively optimize the rehabilitation approaches for improving balance and avoiding falls in individuals with TBI.