Wearable technology for spine movement assessment: A systematic review

Preliminary Validity and Acceptability of Motion Tape for Measuring Low Back Movement: Mixed Methods Study

BACKGROUND

Low back pain (LBP) is a significant public health problem that can result in physical disability and financial burden for the individual and society. Physical therapy is effective for managing LBP and includes evaluation of posture and movement, interventions directed at modifying posture and movement, and prescription of exercises. However, physical therapists have limited tools for objective evaluation of low back posture and movement and monitoring of exercises, and this evaluation is limited to the time frame of a clinical encounter. There is a need for a valid tool that can be used to evaluate low back posture and movement and monitor exercises outside the clinic. To address this need, a fabric-based, wearable sensor, Motion Tape (MT), was developed and adapted for a low back use case. MT is a low-profile, disposable, self-adhesive, skin-strain sensor developed by spray coating piezoresistive graphene nanocomposites directly onto commercial kinesiology tape.

OBJECTIVE

The objectives of this study were to (1) validate MT for measuring low back posture and movement and (2) assess the acceptability of MT for users.

METHODS

A total of 10 participants without LBP were tested. A 3D optical motion capture system was used as a reference standard to measure low back kinematics. Retroreflective markers and a matrix of MTs were placed on the low back to measure kinematics (motion capture) and strain (MT) simultaneously during low back movements in the sagittal, frontal, and axial planes. Cross-correlation coefficients were calculated to evaluate the concurrent validity of MT strain in reference motion capture kinematics during each movement. The acceptability of MT was assessed using semistructured interviews conducted with each participant after laboratory testing. Interview data were analyzed using rapid qualitative analysis to identify themes and subthemes of user acceptability.

RESULTS

Visual inspection of concurrent MT strain and kinematics of the low back indicated that MT can distinguish between different movement directions. Cross-correlation coefficients between MT strain and motion capture kinematics ranged from -0.915 to 0.983, and the strength of the correlations varied across MT placements and low back movement directions. Regarding user acceptability, participants expressed enthusiasm toward MT and believed that it would be helpful for remote interventions for LBP but provided suggestions for improvement.

CONCLUSIONS

MT was able to distinguish between different low back movements, and most MTs demonstrated moderate to high correlation with motion capture kinematics. This preliminary laboratory validation of MT provides a basis for future device improvements, which will also involve testing in a free-living environment. Overall, users found MT acceptable for use in physical therapy for managing LBP.

Reliability and validity of estimated angles information assessed using inertial measurement unit-based motion sensors

BACKGROUND

Inertial measurement unit (IMU)-based motion sensors are affordable, and their use is appropriate for rehabilitation. However, regarding the accuracy of estimated angle information obtained from this sensor, it is reported that it is likely affected by velocity.

OBJECTIVE

The present study investigated the reliability and validity of the angle information obtained using IMU-based sensors compared with a three-dimensional (3D) motion analyzer.

METHODS

The Euler angle obtained using the 3D motion analyzer and the angle obtained using the IMU-based sensor (IMU angle) were compared. Reliability was assessed by comparing the Bland-Altman analysis, intra-class correlation coefficient (ICC) (1,1), and cross-correlation function. The root mean square (RMS) error, ICC (2,1), and cross-correlation function were used to compare data on the Euler and IMU angles to evaluate the validity.

RESULTS

Regarding reliability, the Bland-Atman analysis indicated no fixed or proportional bias in the angle measurements. The measurement errors ranged from 0.2° to 3.2°. In the validity, the RMS error ranged from 0.3° to 2.2°. The ICCs (2,1) were 0.9. The cross-correlation functions were >0.9, which indicated a high degree of agreement.

CONCLUSION

The IMU-based sensor had a high reliability and validity. The IMU angle may be used in rehabilitation.

Assessment of the Acute Effects of Wearable Sensor Derived Auditory Biofeedback on Gross Lumbar Proprioception

Lower back disorders (LBDs) affect a large proportion of the population, and treatment for LBDs have been shifting toward individualized, patient-centered approaches. LBDs are typically associated with poor proprioception. Therefore, there has been a recent uptake in the utilization of wearable sensors that can administer biofeedback in various industrial, clinical, and performance-based settings to improve lumbar proprioception. The aim of this study was to investigate whether wearable sensor-derived acute auditory biofeedback can be used to improve measures of gross lumbar proprioception. To assess this, healthy participants completed an active target repositioning protocol, followed by a training period where lumbar-spine posture referenced auditory feedback was provided for select targets. Target re-matching abilities were captured before and after acute auditory biofeedback training to extract measures related to accuracy and precision across spine flexion targets (i.e., 20%, 40%, 60%, 80% maximum). Results suggest a heterogenous response to proprioceptive training whereby certain individuals and spine flexion targets experienced positive effects (i.e., improved accuracy and precision). Specifically, results suggest that mid-range flexion targets (i.e., 40-60% maximum flexion) benefited most from the acute auditory feedback training. Further, individuals with poorer repositioning abilities in the pre-training assessment showed the greatest improvements from the auditory feedback training.

Validity and reliability of inertial measurement units used to measure motion of the lumbar spine: A systematic review of individuals with and without low back pain

Low back pain (LBP) is a leading cause of disability, resulting in aberrant movement. This movement is difficult to measure accurately in clinical practice and gold standard methods, such as optoelectronic systems involve the use of expensive laboratory equipment. Inertial measurement units (IMU) offer an alternative method of quantifying movement that is accessible in most environments. However, there is no consensus around the validity and reliability of IMUs for quantifying lumbar spine movements compared with gold standard measures. The aim of this systematic review was to establish concurrent validity and repeated measures reliability of using IMUs for the measurement of lumbar spine movements in individuals with and without LBP. A systematic search of electronic databases, incorporating PRISMA guidelines was completed, limited to the English language. 503 studies were identified where 15 studies met the inclusion criteria. Overall, 305 individuals were included, and 109 of these individuals had LBP. Weighted synthesis of the results demonstrated root mean squared differences of <2.4° compared to the gold standard and intraclass correlations >0.84 for lumbar spine movements. IMUs offer clinicians and researchers valid and reliable measurement of motion in the lumbar spine, comparable to laboratory methods, such as optoelectronic motion capture for individuals with and without LBP.

Digital Phenotyping, Wearables, and Outcomes

There is a significant need for robust and objective outcome assessments in spine surgery. Constant monitoring via smartphones and wearable devices has the potential to fill this role by providing an in-depth picture of human well-being, creating an unprecedented amount of objective data to augment clinical decision-making. The metrics obtained from continuous patient monitoring increase the amount and ecological validity of data relevant to spine surgery. This can provide physicians with patient and disease-specific medical information, facilitating personalized patient care.

Lumbo-Pelvic Rhythm Monitoring Using Wearable Technology with Sensory Biofeedback: A Systematic Review

As an essential lower-back movement pattern, lumbo-pelvic rhythm (LPR) during forward trunk flexion and backward return has been investigated on a large scale. It has been suggested that abnormalities in lumbo-pelvic coordination are related to the risk of developing low back disorders. However, considerable differences in the approaches used to monitor LPR make it challenging to integrate findings from those investigations for future research. Therefore, the aim of this systematic review was to summarize the use of wearable technology for kinematic measurement with sensory biofeedback for LPR monitoring by assessing these technologies' specific capabilities and biofeedback capacities and exploring their practical viability based on sensor outcomes. The review was developed following the PRISMA guidelines, and the risk of bias was analyzed using the PREDro and STROBE scales. PubMed, Web of Science, Scopus, and IEEEXPLORE databases were searched for relevant studies, initially returning a total of 528 articles. Finally, we included eight articles featuring wearable devices with audio or vibration biofeedback. Differences in protocols and limitations were also observed. This novel study presents a review of wearable tracking devices for LPR motion-mediated biofeedback for the purpose of correcting lower back posture. More research is needed to determine the long-term effectiveness of these devices, as well as their most appropriate corresponding methodologies.

Usability of a visual feedback system to assess and improve movement disorders related to neck pain: Perceptions of physical therapists and patients

A prototype visual feedback system has been developed to assess and improve movement disorders related to neck pain. The aim of this study was to assess the usability of the prototype in a rehabilitation setting. Twelve physical therapists integrated the device into their regular therapy programs for 24 neck pain patients with movement disorders. Each patient performed three individual therapy sessions with the device under physical therapist supervision. Usability was assessed by the physical therapists and patients using therapy diaries, the System Usability Scale, and focus group or personal interviews. Based on an overall usability rating of marginally acceptable, the visual feedback system was generally found to be a device with the potential to assess and train neck pain patients but needs improvement. To become a useful adjunct to regular physical therapy, improvements in the hardware and software, and further system developments are required.

How Movement Is Assessed Matters. Changes in Forward Bending During Cognitive Functional Therapy Treatment for People With Chronic Low Back Pain

OBJECTIVE: To investigate forward bending range of motion (ROM) and velocity in patients with low back pain who were receiving Cognitive Functional Therapy and determine (1) the amount and timing of change occurring at the trunk and pelvis (global angles), and lumbar spine (intersensor angle), and (2a) differences in changes between participants with and without sensor biofeedback, and (2b) participants with and without baseline movement limitation. DESIGN: Observational study. METHODS: Two hundred sixty-one participants attended Cognitive Functional Therapy treatment and wore sensors at the T12 and S2 spine levels while performing forward bending. Measures included ROM and velocity from both sensors, and the intersensor angle. Regression models estimated changes over time. Time-group interactions tested participants who were subgrouped by treatment and baseline movement. RESULTS: During the 90-day evaluation period, most change occurred in the first 21 days. Changes in ROM observed at T12 (3.3°, 95% CI: 1.0°, 5.5°; P = .001) and S2 (3.3°, 95% CI: 1.2°, 5.4°; P = .002) were similar. Intersensor angle remained similar (0.2°, 95% CI: -2.0°, -1.6°; P = .81). Velocity measured at T12 and S2, and the intersensor angle increased 8.5°/s (95% CI: 6.7°/s, 10.3°/s; P<.0001), 5.3°/s (95% CI: 4.0°/s, 6.5°/s; P<.0001), and 3.4°/s (95% CI: 2.4°/s, 4.5°/s; P<.0001), respectively, for 0 to 21 days. There were minimal differences in participants who received biofeedback. Larger increases occurred in participants with restricted ROM and slower velocity at baseline. CONCLUSION: During 0 to 21 days, we observed changes at the trunk and pelvis (especially in people with reduced ROM), and velocity changes across all measures (especially in people with baseline movement limitations). Biofeedback did not augment the changes. When targeting forward bending in people with low back pain, clinicians should monitor changes in velocity and global ROM. J Orthop Sports Phys Ther 2024;54(3):1-13. Epub 19 December 2023. doi:10.2519/jospt.2023.12023.

Physical Therapists' Acceptance of a Wearable, Fabric-Based Sensor System (Motion Tape) for Use in Clinical Practice: Qualitative Focus Group Study

BACKGROUND

Low back pain (LBP) is a costly global health condition that affects individuals of all ages and genders. Physical therapy (PT) is a commonly used and effective intervention for the management of LBP and incorporates movement assessment and therapeutic exercise. A newly developed wearable, fabric-based sensor system, Motion Tape, uses novel sensing and data modeling to measure lumbar spine movements unobtrusively and thus offers potential benefits when used in conjunction with PT. However, physical therapists' acceptance of Motion Tape remains unexplored.

OBJECTIVE

The primary aim of this research study was to evaluate physical therapists' acceptance of Motion Tape to be used for the management of LBP. The secondary aim was to explore physical therapists' recommendations for future device development.

METHODS

Licensed physical therapists from the American Physical Therapy Association Academy of Leadership Technology Special Interest Group participated in this study. Overall, 2 focus groups (FGs; N=8) were conducted, in which participants were presented with Motion Tape samples and examples of app data output on a poster. Informed by the Technology Acceptance Model, we conducted semistructured FGs and explored the wearability, usefulness, and ease of use of and suggestions for improvements in Motion Tape for PT management of LBP. FG data were transcribed and analyzed using rapid qualitative analysis.

RESULTS

Regarding wearability, participants perceived that Motion Tape would be able to adhere for several days, with some variability owing to external factors. Feedback was positive for the low-profile and universal fit, but discomfort owing to wires and potential friction with clothing was of concern. Other concerns included difficulty with self-application and potential skin sensitivity. Regarding usefulness, participants expressed that Motion Tape would enhance the efficiency and specificity of assessments and treatment. Regarding ease of use, participants stated that the app would be easy, but data management and challenges with interpretation were of concern. Physical therapists provided several recommendations for future design improvements including having a wireless system or removable wires, customizable sizes for the tape, and output including range of motion data and summary graphs and adding app features that consider patient input and context.

CONCLUSIONS

Several themes related to Motion Tape's wearability, usefulness, and ease of use were identified. Overall, physical therapists expressed acceptance of Motion Tape's potential for assessing and monitoring low back posture and movement, both within and outside clinical settings. Participants expressed that Motion Tape would be a valuable tool for the personalized treatment of LBP but highlighted several future improvements needed for Motion Tape to be used in practice.

Wearables for Monitoring and Postural Feedback in the Work Context: A Scoping Review

Wearables offer a promising solution for simultaneous posture monitoring and/or corrective feedback. The main objective was to identify, synthesise, and characterise the wearables used in the workplace to monitor and postural feedback to workers. The PRISMA-ScR guidelines were followed. Studies were included between 1 January 2000 and 22 March 2023 in Spanish, French, English, and Portuguese without geographical restriction. The databases selected for the research were PubMed®, Web of Science®, Scopus®, and Google Scholar®. Qualitative studies, theses, reviews, and meta-analyses were excluded. Twelve studies were included, involving a total of 304 workers, mostly health professionals (n = 8). The remaining studies covered workers in the industry (n = 2), in the construction (n = 1), and welders (n = 1). For assessment purposes, most studies used one (n = 5) or two sensors (n = 5) characterised as accelerometers (n = 7), sixaxial (n = 2) or nonaxialinertial measurement units (n = 3). The most common source of feedback was the sensor itself (n = 6) or smartphones (n = 4). Haptic feedback was the most prevalent (n = 6), followed by auditory (n = 5) and visual (n = 3). Most studies employed prototype wearables emphasising kinematic variables of human movement. Healthcare professionals were the primary focus of the study along with haptic feedback that proved to be the most common and effective method for correcting posture during work activities.

The utility of behavioral biometrics in user authentication and demographic characteristic detection: a scoping review

BACKGROUND

Objective measures of screen time are necessary to better understand the complex relationship between screen time and health outcomes. However, current objective measures of screen time (e.g., passive sensing applications) are limited in identifying the user of the mobile device, a critical limitation in children's screen time research where devices are often shared across a family. Behavioral biometrics, a technology that uses embedded sensors on modern mobile devices to continuously authenticate users, could be used to address this limitation.

OBJECTIVE

The purpose of this scoping review was to summarize the current state of behavioral biometric authentication and synthesize these findings within the scope of applying behavioral biometric technology to screen time measurement.

METHODS

We systematically searched five databases (Web of Science Core Collection, Inspec in Engineering Village, Applied Science & Technology Source, IEEE Xplore, PubMed), with the last search in September of 2022. Eligible studies were on the authentication of the user or the detection of demographic characteristics (age, gender) using built-in sensors on mobile devices (e.g., smartphone, tablet). Studies were required to use the following methods for authentication: motion behavior, touch, keystroke dynamics, and/or behavior profiling. We extracted study characteristics (sample size, age, gender), data collection methods, data stream, model evaluation metrics, and performance of models, and additionally performed a study quality assessment. Summary characteristics were tabulated and compiled in Excel. We synthesized the extracted information using a narrative approach.

RESULTS

Of the 14,179 articles screened, 122 were included in this scoping review. Of the 122 included studies, the most highly used biometric methods were touch gestures (n = 76) and movement (n = 63), with 30 studies using keystroke dynamics and 6 studies using behavior profiling. Of the studies that reported age (47), most were performed exclusively in adult populations (n = 34). The overall study quality was low, with an average score of 5.5/14.

CONCLUSION

The field of behavioral biometrics is limited by the low overall quality of studies. Behavioral biometric technology has the potential to be used in a public health context to address the limitations of current measures of screen time; however, more rigorous research must be performed in child populations first.

SYSTEMATIC REVIEW REGISTRATION

The protocol has been pre-registered in the Open Science Framework database ( https://doi.org/10.17605/OSF.IO/92YCT ).

Concurrent Validity of the Ergotex Device for Measuring Low Back Posture

Highlighting the crucial role of monitoring and quantifying lumbopelvic rhythm for spinal curvature, the Ergotex IMU, a portable, lightweight, cost-effective, and energy-efficient technology, has been specifically designed for the pelvic and lumbar area. This study investigates the concurrent validity of the Ergotex device in measuring sagittal pelvic tilt angle. We utilized an observational, repeated measures design with healthy adult males (mean age: 39.3 ± 7.6 y, body mass: 82.2 ± 13.0 kg, body height: 179 ± 8 cm), comparing Ergotex with a 3D optical tracking system. Participants performed pelvic tilt movements in anterior, neutral, and posterior conditions. Statistical analysis included paired samples t-tests, Bland-Altman plots, and regression analysis. The findings show minimal systematic error (0.08° overall) and high agreement between the Ergotex and optical tracking, with most data points falling within limits of agreement of Bland-Altman plots (around ±2°). Significant differences were observed only in the anterior condition (0.35°, p < 0.05), with trivial effect sizes (ES = 0.08), indicating that these differences may not be clinically meaningful. The high Pearson's correlation coefficients across conditions underscore a robust linear relationship between devices (r > 0.9 for all conditions). Regression analysis showed a standard error of estimate (SEE) of 1.1° with small effect (standardized SEE < 0.26 for all conditions), meaning that the expected average deviation from the true value is around 1°. These findings validate the Ergotex as an effective, portable, and cost-efficient tool for assessing sagittal pelvic tilt, with practical implications in clinical and sports settings where traditional methods might be impractical or costly.

Measuring Outcomes in Spinal Deformity Surgery

Outcome assessment in adult spinal deformity has evolved from radiographic analysis of curve correction to patient-centered perception of health-related quality-of-life. Oswestry Disability Index and the Scoliosis Research Society-22 Patient Questionnaire are the predominantly used patient-reported outcome (PRO) measurements for deformity surgery. Correction of sagittal alignment correlates with improved PRO. Functional outcomes and accelerometer measurements represent newer methods of measuring outcomes but have not yet been widely adopted or validated. Further adoption of a minimum set of core outcome domains will help facilitate international comparisons and benchmarking, and ultimately enhance value-based healthcare.

Digital Biomarkers and the Evolution of Spine Care Outcomes Measures: Smartphones and Wearables

Over the past generation, outcome measures in spine care have evolved from a reliance on clinician-reported assessment toward recognizing the importance of the patient's perspective and the wide incorporation of patient-reported outcomes (PROs). While patient-reported outcomes are now considered an integral component of outcomes assessments, they cannot wholly capture the state of a patient's functionality. There is a clear need for quantitative and objective patient-centered outcome measures. The pervasiveness of smartphones and wearable devices in modern society, which passively collect data related to health, has ushered in a new era of spine care outcome measurement. The patterns emerging from these data, so-called "digital biomarkers," can accurately describe characteristics of a patient's health, disease, or recovery state. Broadly, the spine care community has thus far concentrated on digital biomarkers related to mobility, although the researcher's toolkit is anticipated to expand in concert with advancements in technology. In this review of the nascent literature, we describe the evolution of spine care outcome measurements, outline how digital biomarkers can supplement current clinician-driven and patient-driven measures, appraise the present and future of the field in the modern era, as well as discuss present limitations and areas for further study, with a focus on smartphones (see Supplemental Digital Content , http://links.lww.com/NEU/D809 , for a similar appraisal of wearable devices).

The Use of Sensors to Prevent, Predict Transition to Chronic and Personalize Treatment of Low Back Pain: A Systematic Review

Non-specific low back pain (NSLBP) is a highly prevalent condition that implies substantial expenses and affects quality of life in terms of occupational and recreational activities, physical and psychological health, and general well-being. The diagnosis and treatment are challenging processes due to the unknown underlying causes of the condition. Recently, sensors have been included in clinical practice to implement its management. In this review, we furthered knowledge about the potential benefits of sensors such as force platforms, video systems, electromyography, or inertial measure systems in the assessment process of NSLBP. We concluded that sensors could identify specific characteristics of this population like impaired range of movement, decreased stability, or disturbed back muscular activation. Sensors could provide sufferers with earlier diagnosis, prevention strategies to avoid chronic transition, and more efficient treatment approaches. Nevertheless, the review has limitations that need to be considered in the interpretation of results.

Mechanism, application and effect evaluation of nerve mobilization in the treatment of low back pain: A narrative review

Lower back pain is a prevalent condition affecting people across all age groups and causing significant personal and societal burdens. While numerous treatments exist, nerve mobilization has emerged as a promising approach for managing lower back pain. Nerve mobilization involves applying gentle and rhythmic movements to the affected nerves, promoting normal nerve function and releasing tension. It has been well documented that nerve mobilization can be effective in reducing pain and improving function in patients with lower back pain, but the underlying mechanisms have not been clarified. This study aims to review the mechanisms of nerve mobilization in the management of lower back pain, its application, and effectiveness evaluation, and provide a potential solution for managing lower back pain.

Validity of an inertial measurement unit for the assessment of range and quality of movement during head and thoracic spine movements

BACKGROUND

Patients with spinal pain often exhibit movement limitations and altered motor control, which can be challenging to measure accurately in clinical practice. Inertial measurement sensors present a promising new opportunity to develop valid, low-cost, and easy-to-use methods for assessing and monitoring spinal motion in a clinical setting.

AIM

This study aimed to investigate the agreement of an inertial sensor and a 3D camera system for assessing the range of motion (ROM) and quality of movement (QOM) in head and trunk single-plane movements.

METHODS

Thirty-three healthy, pain-free volunteers were included. Each participant performed movements of the head (cervical flexion, extension, and lateral flexion) and trunk (trunk flexion, extension, rotation, and lateral flexion), which were simultaneously recorded by a 3D camera system and an inertial measurement unit (MOTI, Aalborg, Denmark). Agreement and consistency were analyzed for ROM and QOM by determining intraclass correlation coefficients (ICC), mean bias, and with Bland-Altman plots.

RESULTS

The agreement between systems was excellent for all movements (ICC between 0.91 and 1.00) for ROM and good to excellent for the QOM (ICC between 0.84 and 0.95). The mean bias for all movements (0.1-0.8°) was below the minimum acceptable difference between devices. The Bland-Altman plot indicated that MOTI systematically measured a slightly greater ROM and QOM than the 3D camera system for all neck and trunk movements.

CONCLUSION

This study showed that MOTI is a feasible and potentially applicable option to assess ROM and QOM for head and trunk movements in experimental and clinical settings.

Effect of neglecting passive spinal structures: a quantitative investigation using the forward-dynamics and inverse-dynamics musculoskeletal approach

Purpose: Inverse-dynamics (ID) analysis is an approach widely used for studying spine biomechanics and the estimation of muscle forces. Despite the increasing structural complexity of spine models, ID analysis results substantially rely on accurate kinematic data that most of the current technologies are not capable to provide. For this reason, the model complexity is drastically reduced by assuming three degrees of freedom spherical joints and generic kinematic coupling constraints. Moreover, the majority of current ID spine models neglect the contribution of passive structures. The aim of this ID analysis study was to determine the impact of modelled passive structures (i.e., ligaments and intervertebral discs) on remaining joint forces and torques that muscles must balance in the functional spinal unit. Methods: For this purpose, an existing generic spine model developed for the use in the demoa software environment was transferred into the musculoskeletal modelling platform OpenSim. The thoracolumbar spine model previously used in forward-dynamics (FD) simulations provided a full kinematic description of a flexion-extension movement. By using the obtained in silico kinematics, ID analysis was performed. The individual contribution of passive elements to the generalised net joint forces and torques was evaluated in a step-wise approach increasing the model complexity by adding individual biological structures of the spine. Results: The implementation of intervertebral discs and ligaments has significantly reduced compressive loading and anterior torque that is attributed to the acting net muscle forces by -200% and -75%, respectively. The ID model kinematics and kinetics were cross-validated against the FD simulation results. Conclusion: This study clearly shows the importance of incorporating passive spinal structures on the accurate computation of remaining joint loads. Furthermore, for the first time, a generic spine model was used and cross-validated in two different musculoskeletal modelling platforms, i.e., demoa and OpenSim, respectively. In future, a comparison of neuromuscular control strategies for spinal movement can be investigated using both approaches.

Recognizing Human Activity of Daily Living Using a Flexible Wearable for 3D Spine Pose Tracking

The World Health Organization recognizes physical activity as an influencing domain on quality of life. Monitoring, evaluating, and supervising it by wearable devices can contribute to the early detection and progress assessment of diseases such as Alzheimer's, rehabilitation, and exercises in telehealth, as well as abrupt events such as a fall. In this work, we use a non-invasive and non-intrusive flexible wearable device for 3D spine pose measurement to monitor and classify physical activity. We develop a comprehensive protocol that consists of 10 indoor, 4 outdoor, and 8 transition states activities in three categories of static, dynamic, and transition in order to evaluate the applicability of the flexible wearable device in human activity recognition. We implement and compare the performance of three neural networks: long short-term memory (LSTM), convolutional neural network (CNN), and a hybrid model (CNN-LSTM). For ground truth, we use an accelerometer and strips data. LSTM reached an overall classification accuracy of 98% for all activities. The CNN model with accelerometer data delivered better performance in lying down (100%), static (standing = 82%, sitting = 75%), and dynamic (walking = 100%, running = 100%) positions. Data fusion improved the outputs in standing (92%) and sitting (94%), while LSTM with the strips data yielded a better performance in bending-related activities (bending forward = 49%, bending backward = 88%, bending right = 92%, and bending left = 100%), the combination of data fusion and principle components analysis further strengthened the output (bending forward = 100%, bending backward = 89%, bending right = 100%, and bending left = 100%). Moreover, the LSTM model detected the first transition state that is similar to fall with the accuracy of 84%. The results show that the wearable device can be used in a daily routine for activity monitoring, recognition, and exercise supervision, but still needs further improvement for fall detection.

Systematic analysis of different low-pass filter cut-off frequencies on lumbar spine kinematics data and the impact on the agreement between accelerometers and an optoelectronic system

A necessary step in the validation of accelerometers for the measurement of spine angles is to determine the levels of agreement with current gold standard methods. However, agreement may be a function of filtering parameters. We aimed to (1) systematically determine the effect of different filter frequency cut-offs on the peak range of motion (ROM) during forward bending as measured by accelerometers and an optoelectronic (OE) system, (2) explore the influence of filtering on agreement between systems, and (3) determine the difference in peak ROM measurement between these systems. Accelerometers and OE sensors were attached at L2, L4, and S1 of 20 asymptomatic female participants for a guided flexion trial. Signals were then iteratively low-pass filtered with cut-off frequencies ranging from 14 Hz to 1 Hz and peak range of motion outcome measures were compared between systems. Peak ROM was minimally affected by filter cut-off frequency for both accelerometer and OE system. The difference in peak ROM between difference cut-off frequencies were maximum 0.66°, median 0.18° and minimum 0.06° for accelerometer derived values and maximum 0.23°, median 0.08° and minimum 0.03° for the OE system. The maximum difference across the filtering frequencies was 0.62° and the largest difference between the two systems (with outliers removed) was 0.82°. Cut-off frequencies ranging from 14 to 1 Hz had little effect of peak lumbar spine ROM during low velocity (6°/s) forward bending, regardless of motion capture method. Filtering cut-off frequency had little effect on the differences between the accelerometer and OE system and similar measurements can be achieved using accelerometers compared to OE systems.

Progress in Data Acquisition of Wearable Sensors

Wearable sensors have demonstrated wide applications from medical treatment, health monitoring to real-time tracking, human-machine interface, smart home, and motion capture because of the capability of in situ and online monitoring. Data acquisition is extremely important for wearable sensors, including modules of probes, signal conditioning, and analog-to-digital conversion. However, signal conditioning, analog-to-digital conversion, and data transmission have received less attention than probes, especially flexible sensing materials, in research on wearable sensors. Here, as a supplement, this paper systematically reviews the recent progress of characteristics, applications, and optimizations of transistor amplifiers and typical filters in signal conditioning, and mainstream analog-to-digital conversion strategies. Moreover, possible research directions on the data acquisition of wearable sensors are discussed at the end of the paper.

Concurrent validity of DorsaVi wireless motion sensor system Version 6 and the Vicon motion analysis system during lifting

Background

Wearable sensor technology may allow accurate monitoring of spine movement outside a clinical setting. The concurrent validity of wearable sensors during multiplane tasks, such as lifting, is unknown. This study assessed DorsaVi Version 6 sensors for their concurrent validity with the Vicon motion analysis system for measuring lumbar flexion during lifting.

Methods

Twelve participants (nine with, and three without back pain) wore sensors on T12 and S2 spinal levels with Vicon surface markers attached to those sensors. Participants performed 5 symmetrical (lifting from front) and 20 asymmetrical lifts (alternate lifting from left and right). The global-T12-angle, global-S2-angle and the angle between these two sensors (relative-lumbar-angle) were output in the sagittal plane. Agreement between systems was determined through-range and at peak flexion, using multilevel mixed-effects regression models to calculate root mean square errors and standard deviation. Mean differences and limits of agreement for peak flexion were calculated using the Bland Altman method.

Results

For through-range measures of symmetrical lifts, root mean squared errors (standard deviation) were 0.86° (0.78) at global-T12-angle, 0.90° (0.84) at global-S2-angle and 1.34° (1.25) at relative-lumbar-angle. For through-range measures of asymmetrical lifts, root mean squared errors (standard deviation) were 1.84° (1.58) at global-T12-angle, 1.90° (1.65) at global-S2-angle and 1.70° (1.54) at relative-lumbar-angle. The mean difference (95% limit of agreement) for peak flexion of symmetrical lifts, was − 0.90° (-6.80 to 5.00) for global-T12-angle, 0.60° (-2.16 to 3.36) for global-S2-angle and − 1.20° (-8.06 to 5.67) for relative-lumbar-angle. The mean difference (95% limit of agreement) for peak flexion of asymmetrical lifts was − 1.59° (-8.66 to 5.48) for global-T12-angle, -0.60° (-7.00 to 5.79) for global-S2-angle and − 0.84° (-8.55 to 6.88) for relative-lumbar-angle.

Conclusion

The root means squared errors were slightly better for symmetrical lifts than they were for asymmetrical lifts. Mean differences and 95% limits of agreement showed variability across lift types. However, the root mean squared errors for all lifts were better than previous research and below clinically acceptable thresholds. This research supports the use of lumbar flexion measurements from these inertial measurement units in populations with low back pain, where multi-plane lifting movements are assessed.

The deer play in Wuqinxi and four-point hand−knee kneeling positions for training core muscle function and spinal mobility

The four-point kneeling exercise is a core stabilization exercise that provides the spine with dynamic stability and neuromuscular control. In the traditional Chinese exercise Wuqinxi, deer play is performed in a hand−foot kneeling (HFK) position, which is remarkably similar to the four-point hand−knee kneeling (HKK) position. However, the differences in spinal function promotion between these two positions are poorly understood. The aim of this study was to investigate muscle activation patterns and spinal kinematics during specific core stabilization training to provide evidence for selecting specific exercises. A total of 19 healthy adults were recruited to perform HFK and HKK. The rotation angle of the C7–T4 vertebra and the surface EMG signals of abdominal and lumbar muscles on both sides were collected. The paired t-test showed that the vertebral rotation angles were significantly higher during HKK than HFK, and the intra-group differences mainly occurred at the level of the thoracic vertebra. The muscle activation of both sides of the rectus abdominis and external oblique in HFK was significantly higher than in HKK when the upper limb was lifted (p < 0.05). The activation of the ipsilateral lumbar multifidus and erector spinae muscles was significantly higher during the HKK position than during HFK when the lower limb was lifted (p < 0.05). HFK provided more training for strengthening abdominal muscles, while HKK could be recommended for strengthening lumbar muscles and increasing spine mobility. These findings can be used to help physiotherapists, fitness coaches, and others to select specific core exercises and develop individualized training programs.

Lower Limbs Wearable Sports Garments for Muscle Recovery: An Umbrella Review

This review aims to understand the different technologies incorporated into lower limbs wearable smart garments and their impact on post-exercise recovery. Electronic searches were conducted in the PubMed, Web of Science, and Cochrane electronic databases. Eligibility criteria considered meta-analyses that examined the effects of wearable smart garments on physical fitness in healthy male and female adults. Seven meta-analyses were considered in the current umbrella review, indicating small effects on delayed-onset muscle soreness ([0.40–0.43]), rate of perceived exertion (0.20), proprioception (0.49), anaerobic performance (0.27), and sprints ([0.21–0.37]). The included meta-analyses also indicated wearable smart garments have trivial to large effects on muscle strength and power ([0.14–1.63]), creatine kinase ([0.02–0.44]), lactate dehydrogenase (0.52), muscle swelling (0.73), lactate (0.98) and aerobic pathway (0.24), and endurance (0.37), aerobic performance (0.60), and running performance ([0.06–6.10]). Wearing wearable smart garments did not alter the rate of perceived exertion and had a small effect on delayed-onset muscle soreness. Well-fitting wearable smart garments improve comfort and kinesthesia and proprioception and allow a reduction in strength loss and muscle damage after training and power performance following resistance training or eccentric exercise.

Movement Analysis Could Help in the Assessment of Chronic Low Back Pain Patients: Results from a Preliminary Explorative Study

Introduction: This study aimed to assess the reliability of a qualitative scoring system based on the movement analysis of the spine in different populations and after usual care rehabilitative intervention. If proven true, the results could further future research development in quantitative indexes, leading to a possible subclassification of chronic low back pain (cLBP). Methods: This was a preliminary exploratory observational study. Data of an optoelectronic spine movement analysis from a pathological population (cLBP population, 5 male, 5 female, age 58 ± 16 years) were compared to young healthy participants (5M, 5F, age 22 ± 1) and were analysed via a new qualitative score of the pattern of movement. Internal consistency was calculated. Two independent assessors (experienced and inexperienced) assessed the blinded data, and we calculated inter- and intrarater reliability. We performed an analysis for cLBP pre and post a ten session group rehabilitation program between and within groups. Results: Internal consistency was good for all movements (α = 0.84-0.88). Intra-rater reliability (Intraclass correlation coefficient-ICC) was excellent for overall scores of all movements (ICC_(1,k) = 0.95-0.99), while inter-rater reliability was poor to moderate (ICC_(1,k) = 0.39-0.78). We found a significant difference in the total movement scores between cLBP and healthy participants (p = 0.001). Within-group comparison (cLBP) showed no significant difference in the total movement score in pre and post-treatment. Conclusion: The perception of differences between normal and pathological movements has been confirmed through the proposed scoring system, which proved to be able to distinguish different populations. This study has many limitations, but these results show that movement analysis could be a useful tool and open the door to quantifying the identified parameters through future studies.

Design considerations for piezocomposite materials for electrical stimulation in medical implants

Incidence of non-union following long bone fracture fixation and spinal fusion procedures is increasing, and very costly for patients and the medical system. Direct current (DC) electrical stimulation has shown success as an adjunct therapy to stimulate bone healing and increase surgery success rates, though drawbacks of current devices and implantable battery packs have limited widespread use. Energy harvesting utilising piezoelectric materials has been widely studied for powering devices without a battery, and a preclinical animal study has shown efficacy of a piezocomposite spinal fusion implant resulting in faster, more robust fusion. Most piezoelectric energy harvesters operate most effectively at high frequencies, limiting power generation from loads experienced by orthopaedic implants during human motion. This work characterises the efficient power generation capability of a novel composite piezoelectric material under simulated walking loads. Building on compliant layer adaptive composite stacks (CLACS), the power generation of mixed-mode CLACS (MMCLACS) is defined. Utilising poling direction to capitalise on in-plane strain generation due to compliant layer expansion, MMCLACS significantly increased power output compared to a standard piezo stack. The combination of radial and through-thickness poled piezoelectric elements within a stack to create MMCLACS significantly increases power generation under low-frequency dynamic loads. This technology can be adapted to a variety of architectures and assembled as a load-bearing energy harvester within current implants. MMCLACS integrated with implants would provide enough power to deliver bone healing electrical stimulation directly to the fusion site, decreasing non-union rates, and also could provide quantitative assessment of healing progression through load sensing.

Use of accelerometry to investigate standing and dynamic body balance in people with cerebral palsy: A systematic review

BACKGROUND

People with cerebral palsy (CP) often have difficulties related to maintaining body balance in their daily living activities. Accelerometers are low-cost wearable devices with potential use to objectively assess balance.

RESEARCH QUESTION

What are the main characteristics and findings from protocols used in research aiming to investigate standing or dynamic body balance stability through trunk accelerometry in people with CP?

METHOD

We searched in December 2021 seven databases, Pubmed, Embase, Cochrane, Science Direct, Scopus, PEDro, and Lilacs, with descriptors related to cerebral palsy, accelerometer, and balance.

RESULTS

Ten studies were included, with a total of 197 evaluated people with CP. These studies were classified as moderate or high methodological quality. We found convergence on the use of the sensor at the lumbar region (L3), with sampling frequency at 100 Hz. For balance assessment, 60 % of the reviewed studies used the 10-m walk test, while the other studies used different walking distances, or the quiet standing test. For data processing, the low-pass filter at 20 Hz has been used predominantly, and the most commonly used variable to evaluate balance stability has been root mean square of trunk acceleration. Children and adolescents with CP had higher acceleration values and greater gait complexity than typically developing children. Individuals with bilateral impairment had greater anteroposterior and mediolateral trunk accelerations than those with unilateral impairment. Trunk acceleration was shown to be sensitive to improvement in gait stability from interventions, and acceleration-based measures have been found to correlate with qualitative balance assessment tools.

SIGNIFICANCE

Trunk accelerometry in quiet posture and dynamic tasks was shown to be a valid and sensitive measurement to evaluate balance stability in children and adolescents with CP. It is a small, light, low-cost and easy-to-handle tool that is effective for measuring body balance on different tasks in this population.

Detecting Low Back Physiotherapy Exercises and Postures with Inertial Sensors and Machine Learning (Preprint)

Background

Objective

Methods

Results

Conclusions

The Stoop-Squat-Index: a simple but powerful measure for quantifying whole-body lifting behavior

Background

Most of the studies evaluating lifting behavior only focus on very localized parameters such as lumbar spine flexion, while evaluations of whole-body strategies are largely lacking. To enable relatively simple evaluations of whole-body strategies, this study aimed at developing a novel index for quantifying the stoop-squat behavior, and to establish normative values of the index for healthy pain-free adults.

Methods

A novel index, the Stoop-Squat-Index, was developed, which describes the proportion between trunk forward lean and lower extremity joint flexion, with possible values ranging from 0 (full squat lifting) to 100 (full stoop lifting). To enable the interpretation of the index in a real-life setting, normative values for lifting a moderately-weighted object (15-kg-box) with a full squat and a full stoop technique were established using motion capture data from 30 healthy pain-free individuals that underwent motion analysis of squat and stoop lifting in the context of a previously conducted study.

Results

The results showed mean index values of lower than 30 and higher than 90 for the most relevant phases of the squat and stoop movements, respectively, with mean index values differing significantly from each other for the full duration of the lifting phases.

Conclusions

The main advantages of the index are that it is simple to calculate and can not only be derived from motion capture data but also from conventional video recordings, which enables large-scale in-field measurements with relatively low expenditure. When used in combination with lumbar spine flexion measurements, the index can contribute important information, which is necessary for comprehensively evaluating whole-body lifting strategies and to shed more light on the debate over the connection between lifting posture and back complaints.

A vision for the future of wearable sensors in spine care and its challenges: narrative review

OBJECTIVE

This review aimed to: (I) provide a brief overview of some topical areas of current literature regarding applications of wearable sensors in the management of low back pain (LBP); (II) present a vision for a future comprehensive system that integrates wearable sensors to measure multiple parameters in the real world that contributes data to guide treatment selection (aided by artificial intelligence), uses wearables to aid treatment support, adherence and outcome monitoring, and interrogates the response of the individual patient to the prescribed treatment to guide future decision support for other individuals who present with LBP; and (III) consider the challenges that will need to be overcome to make such a system a reality.

BACKGROUND

Advances in wearable sensor technologies are opening new opportunities for the assessment and management of spinal conditions. Although evidence of improvements in outcomes for individuals with LBP from the use of sensors is limited, there is enormous future potential.

METHODS

Narrative review and literature synthesis.

CONCLUSIONS

Substantial research is underway by groups internationally to develop and test elements of this system, to design innovative new sensors that enable recording of new data in new ways, and to fuse data from multiple sources to provide rich information about an individual's experience of LBP. Together this system, incorporating data from wearable sensors has potential to personalise care in ways that were hitherto thought impossible. The potential is high but will require concerted effort to develop and ultimately will need to be feasible and more effective than existing management.

A Wearable System Based on Multiple Magnetic and Inertial Measurement Units for Spine Mobility Assessment: A Reliability Study for the Evaluation of Ankylosing Spondylitis

Spinal mobility assessment is essential for the diagnostic of patients with ankylosing spondylitis. BASMI is a routine clinical evaluation of the spine; its measurements are made with goniometers and tape measures, implying systematic errors, subjectivity, and low sensitivity. Therefore, it is crucial to develop better mobility assessment methods. The design, implementation, and evaluation of a novel system for assessing the entire spine’s motion are presented. It consists of 16 magnetic and inertial measurement units (MIMUs) communicated wirelessly with a computer. The system evaluates the patient’s movements by implementing a sensor fusion of the triaxial gyroscope, accelerometer, and magnetometer signals using a Kalman filter. Fifteen healthy participants were assessed with the system through six movements involving the entire spine to calculate continuous kinematics and maximum range of motion (RoM). The intrarater reliability was computed over the observed RoM, showing excellent reliability levels (intraclass correlation >0.9) in five of the six movements. The results demonstrate the feasibility of the system for further clinical studies with patients. The system has the potential to improve the BASMI method. To the best of our knowledge, our system involves the highest number of sensors, thus providing more objective information than current similar systems.

Detection of Typical Compensatory Movements during Autonomously Performed Exercises Preventing Low Back Pain (LBP)

With the growing number of people seeking medical advice due to low back pain (LBP), individualised physiotherapeutic rehabilitation is becoming increasingly relevant. Thirty volunteers were asked to perform three typical LBP rehabilitation exercises (Prone-Rocking, Bird-Dog and Rowing) in two categories: clinically prescribed exercise (CPE) and typical compensatory movement (TCM). Three inertial sensors were used to detect the movement of the back during exercise performance and thus generate a dataset that is used to develop an algorithm that detects typical compensatory movements in autonomously performed LBP exercises. The best feature combinations out of 50 derived features displaying the highest capacity to differentiate between CPE and TCM in each exercise were determined. For classifying exercise movements as CPE or TCM, a binary decision tree was trained with the best performing features. The results showed that the trained classifier is able to distinguish CPE from TCM in Bird-Dog, Prone-Rocking and Rowing with up to 97.7% (Head Sensor, one feature), 98.9% (Upper back Sensor, one feature) and 80.5% (Upper back Sensor, two features) using only one sensor. Thus, as a proof-of-concept, the introduced classification models can be used to detect typical compensatory movements in autonomously performed LBP exercises.

Wearable Technology to Increase Self-Awareness of Low Back Pain: A Survey of Technology Needs among Health Care Workers

Low back pain (LBP) is a leading contributor to musculoskeletal injury worldwide and carries a high economic cost. The healthcare industry is the most burdened, with nurses, in particular, being highly prone to LBP. Wearable technologies have the potential to address the challenges of monitoring postures that contribute to LBP and increase self-awareness of workplace postures and movements. We aimed to gain insight into workers’ perceptions of LBP and whether they would consider using wearable monitoring technologies to reduce injury risks. We conducted a cross-sectional survey to gather information from a selected population of nurses. Sixty-four participants completed the survey, and data were analyzed with the support of Machine Learning techniques. Findings from this study indicate that the surveyed population (64 nurses) is interested in these new approaches to monitor movement and posture in the workplace. This technology can potentially change the way ergonomic guidelines are implemented in this population.

Classification of Single-Axis Spinal Motion Using a Wearable System of Stretch Sensors for At-home Physical Therapy

Physical therapy (PT) has demonstrated therapeutic effectiveness for treating low back pain, a prevalent health condition. However, it is challenging to achieve such effectiveness through at-home PT without supervision of a therapist. Towards enabling realtime biofeedback for ensuring correct execution of PT exercises at home, we are building a wearable system that employs light-weight stretch sensors for estimating the spinal posture of a patient performing PT exercises. A basic task is to detect single-axis spinal motions from the sensor measurements. This work presents the design and evaluation of our approach for this task. Three subjects of different body shapes were recruited to wear the system and perform sequences of arbitrary single-axis spinal exercises. The collected data were used to train and test an SVM-based classification algorithm. Experimental results demonstrate that it is feasible to rely on only a small number of stretch sensors to estimate the spinal motion. The results also suggest the existence of strong inter-person variability and thus a practical system should include calibration for ensuring high accuracy.

Survey of Human Gait Analysis and Recognition for Medical and Forensic Applications

Gait is a behavioural biometric which sometimes changes due to diseases but it is still a strong identification metric that is widely used in forensic works, state biometric preserve sectors, and medical laboratories. Gait analysis sometimes helps to identify person’s present mental state which reflects on physiological therapy for improved biological system. There are various gait measurement forms which expand the research area from crime detection to medical enhancement. Many research works have been done so far for gait recognition. Many researchers focused on skeleton image of people to extract gait features and many worked on stride length. Various sensors have been used to detect gait in various light forms. This paper is a brief survey of works on gait recognition, collected from various sources of science and technology literature. We have discussed few efficient models that worked best as well as we have discussed about few data sets available.

Evaluating a wearable biofeedback device for reducing end-range sagittal lumbar spine flexion among home caregivers

Caregivers who work in the home environment are at risk of back injury due to the awkward postures they have to adopt while providing care. Real-time biofeedback provided by a recently developed wearable device (PostureCoach) may be able to reduce this risk. The effectiveness of a two-day training intervention (including PostureCoach and an educational video) was evaluated for its ability to decrease the amount of time spent in end-range spine flexion. Twenty novice caregivers repeated a series of simulated care tasks. Real-time auditory biofeedback was provided to the intervention group (n = 10) when participants' sagittal lumbar spine flexion exceeded a preset threshold during training trials. Participants in the control group (n = 10) received no feedback. Participants repeated the tasks again two weeks and two months post-intervention. The intervention group maintained decreased end-range (80th and 95th percentile) spine flexion compared to controls at both post-intervention time points.

Low Back Pain-Behavior Correction by Providing Haptic Feedbacks: A Preliminary Investigation

The activities performed by nurses in their daily activities involve frequent forward bending and awkward back postures. These movements contribute to the prevalence and development of low back pain (LBP). In previous studies, it has been shown that modifying their posture by education and training in proper lifting techniques decreases the prevalence of LBP. However, this education and training needs to be implemented daily. Hence, implementing the use of a wearable device to monitor the back posture with haptic feedback would be of importance to prevent LBP. This paper proposes a wearable device to monitor the back posture of the user and provide feedback when the participant is performing a possible hurtful movement. In this study, a group of participants was asked to wear the device while performing three of the most common activities performed by nurses. The study was divided into three sessions: In the first session, the participants performed the activities without feedback (baseline). During the second session, the participants received feedback from the wearable device (training) while performing the three tasks. Finally, for the third session, the participants performed the three tasks again, but the haptic feedback was turned off (validation). We found an improvement in the posture of more than 40% for the pitch (lateral bending) and roll (forward/backward bending) axes and 7% for the yaw (twisting) axis when comparing to the results from session 1 and session 2. The comparison between session 1 and session 3 showed an overall improvement of more than 50% for the pitch (lateral bending) and roll (forward/backward bending) axes and more than 20% for the yaw axis. These results hinted at the impact of the haptic feedback on the participants to correct their posture.

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, 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 past 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, though 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 use 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. This article is protected by copyright. All rights reserved.

Classification and Automated Interpretation of Spinal Posture Data Using a Pathology-Independent Classifier and Explainable Artificial Intelligence (XAI)

Clinical classification models are mostly pathology-dependent and, thus, are only able to detect pathologies they have been trained for. Research is needed regarding pathology-independent classifiers and their interpretation. Hence, our aim is to develop a pathology-independent classifier that provides prediction probabilities and explanations of the classification decisions. Spinal posture data of healthy subjects and various pathologies (back pain, spinal fusion, osteoarthritis), as well as synthetic data, were used for modeling. A one-class support vector machine was used as a pathology-independent classifier. The outputs were transformed into a probability distribution according to Platt's method. Interpretation was performed using the explainable artificial intelligence tool Local Interpretable Model-Agnostic Explanations. The results were compared with those obtained by commonly used binary classification approaches. The best classification results were obtained for subjects with a spinal fusion. Subjects with back pain were especially challenging to distinguish from the healthy reference group. The proposed method proved useful for the interpretation of the predictions. No clear inferiority of the proposed approach compared to commonly used binary classifiers was demonstrated. The application of dynamic spinal data seems important for future works. The proposed approach could be useful to provide an objective orientation and to individually adapt and monitor therapy measures pre- and post-operatively.

A Symposium on the Clinic of the Future and Telehealth: Highlights and Future Directions

Children’s National Hospital held a virtual symposium on “The Clinic of the Future and Telehealth” in December 2020. The goal of the symposium was to explore future trends in these domains. We also discussed how the coronavirus disease 2019 (COVID-19) pandemic accelerated ongoing changes in healthcare. We explored what is on the horizon in these fields and how these changes might affect care delivery in the future. Specifically, we discussed the “Clinic of the Future” with clinical teams from genetics and metabolism, orthopedic surgery, and primary care while our telehealth discussion involved genetics and metabolism, psychiatry, and telerehabilitation. As one example, wearable technology could be adopted among primary care practices and drive a shift in outpatient care from center-based care to patient-based care. We also examined technological innovations in physical exam instruments, gait analysis, imaging integration, and cast technology that could modernize the orthopedic surgery clinic. Telemedicine has rapidly expanded among all fields of medicine, especially since the COVID-19 pandemic, and has spurred innovation to improve the effectiveness of virtual physician visits. The development of technology to improve the virtual physical exam, during a telemedicine visit, further increases the utility of online appointments and increases access to care in all specialties. The incorporation of photogrammetry technology, in genetics and metabolism dysmorphology exams, will offer standardized tracking of patients that could improve diagnosis and treatment. Psychiatry has found nearly equal efficacy in diagnosis and treatment with telehealth visits and the additional benefit of gaining insight in the setting of the patients’ home. Robotics has become increasingly common in rehabilitation, which can now incorporate a gaming experience that can be remotely updated and increase engagement and adherence in pediatric patients. The continued exploration of new ideas promises to improve both in-person and virtual care options.

Measuring Spinal Mobility Using an Inertial Measurement Unit System: A Reliability Study in Axial Spondyloarthritis

The objectives of this study were to evaluate the reliability of wearable inertial motion unit (IMU) sensors in measuring spinal range of motion under supervised and unsupervised conditions in both laboratory and ambulatory settings. A secondary aim of the study was to evaluate the reliability of composite IMU metrology scores (IMU-ASMI (Amb)). Forty people with axSpA participated in this clinical measurement study. Participant spinal mobility was assessed by conventional metrology (Bath Ankylosing Spondylitis Metrology Index, linear version—BASMI_Lin) and by a wireless IMU sensor-based system which measured lumbar flexion-extension, lateral flexion and rotation. Each sensor-based movement test was converted to a normalized index and used to calculate IMU-ASMI (Amb) scores. Test-retest reliability was evaluated using intra-class correlation coefficients (ICC). There was good to excellent agreement for all spinal range of movements (ICC > 0.85) and IMU-ASMI (Amb) scores (ICC > 0.87) across all conditions. Correlations between IMU-ASMI (Amb) scores and conventional metrology were strong (Pearson correlation ≥ 0.85). An IMU sensor-based system is a reliable way of measuring spinal lumbar mobility in axSpA under supervised and unsupervised conditions. While not a replacement for established clinical measures, composite IMU-ASMI (Amb) scores may be reliably used as a proxy measure of spinal mobility.

Monitoring of Sitting Postures With Sensor Networks in Controlled and Free-living Environments: Systematic Review

BACKGROUND

A majority of employees in the industrial world spend most of their working time in a seated position. Monitoring sitting postures can provide insights into the underlying causes of occupational discomforts such as low back pain.

OBJECTIVE

This study focuses on the technologies and algorithms used to classify sitting postures on a chair with respect to spine and limb movements, using sensors and wearables such as inertial measurement units, pressure or piezoresistive sensors, accelerometers or gyroscopes, combined with machine learning approaches.

METHODS

A total of three electronic literature databases were surveyed to identify studies classifying sitting postures in adults. Quality appraisal was performed to extract critical details and assess biases in the shortlisted papers.

RESULTS

A total of 14 papers were shortlisted from 952 papers obtained after a systematic search. The majority of the studies used pressure sensors to measure sitting postures, whereas neural networks were the most frequently used approaches for classification tasks in this context. Only 2 studies were performed in a free-living environment. Most studies presented ethical and methodological shortcomings. Moreover, the findings indicate that the strategic placement of sensors can lead to better performance and lower costs.

CONCLUSIONS

The included studies differed in various aspects of design and analysis. The majority of studies were rated as medium quality according to our assessment. Our study suggests that future work for posture classification can benefit from using inertial measurement unit sensors, since they make it possible to differentiate among spine movements and similar postures, considering transitional movements between postures, and using three-dimensional cameras to annotate the data for ground truth. Finally, comparing such studies is challenging, as there are no standard definitions of sitting postures that could be used for classification. In addition, this study identifies five basic sitting postures along with different combinations of limb and spine movements to help guide future research efforts.

Accelerometric Assessment of Postural Balance in Children: A Systematic Review

The correct development of postural control in children is fundamental to ensure that they fully reach their psychomotor capacities. However, this capacity is one of the least studied in the clinical and academic scope regarding children. The objective of this study was to analyze the degree of implementation of accelerometry as an evaluation technique for postural control in children and how it is being used.

METHODS

A systematic search was conducted in PubMed, SpringerLink, SportsDiscus, Medline, Scopus, and Web of Science with the following terms: balance, postural control, children, kids, accelerometry, and accelerometer.

RESULTS

The search generated a total of 18 articles. Two groups of studies were differentiated: those which exclusively included healthy individuals (n = 5) and those which included children with pathologies (n = 13). Accelerometry is being used in children mainly to assess the gait and static balance, as well as to identify the differences between healthy children and children with developmental disorders.

CONCLUSIONS

Accelerometry has a discrete degree of implementation as an evaluation tool to assess postural control. It is necessary to define a systematic method for the evaluation of postural control in pediatrics, in order to delve into the development of this capacity and its alterations in different neurodevelopmental disorders.

Digital Phenotyping and Patient-Generated Health Data for Outcome Measurement in Surgical Care: A Scoping Review

Digital phenotyping-the moment-by-moment quantification of human phenotypes in situ using data related to activity, behavior, and communications, from personal digital devices, such as smart phones and wearables-has been gaining interest. Personalized health information captured within free-living settings using such technologies may better enable the application of patient-generated health data (PGHD) to provide patient-centered care. The primary objective of this scoping review is to characterize the application of digital phenotyping and digitally captured active and passive PGHD for outcome measurement in surgical care. Secondarily, we synthesize the body of evidence to define specific areas for further work. We performed a systematic search of four bibliographic databases using terms related to "digital phenotyping and PGHD," "outcome measurement," and "surgical care" with no date limits. We registered the study (Open Science Framework), followed strict inclusion/exclusion criteria, performed screening, extraction, and synthesis of results in line with the PRISMA Extension for Scoping Reviews. A total of 224 studies were included. Published studies have accelerated in the last 5 years, originating in 29 countries (mostly from the USA, n = 74, 33%), featuring original prospective work (n = 149, 66%). Studies spanned 14 specialties, most commonly orthopedic surgery (n = 129, 58%), and had a postoperative focus (n = 210, 94%). Most of the work involved research-grade wearables (n = 130, 58%), prioritizing the capture of activity (n = 165, 74%) and biometric data (n = 100, 45%), with a view to providing a tracking/monitoring function (n = 115, 51%) for the management of surgical patients. Opportunities exist for further work across surgical specialties involving smartphones, communications data, comparison with patient-reported outcome measures (PROMs), applications focusing on prediction of outcomes, monitoring, risk profiling, shared decision making, and surgical optimization. The rapidly evolving state of the art in digital phenotyping and capture of PGHD offers exciting prospects for outcome measurement in surgical care pending further work and consideration related to clinical care, technology, and implementation.

Effects of smart garments on the well-being of athletes: a scoping review protocol

INTRODUCTION

With the advancements in wearable electronics, electronically integrated smart garments started to transpire in our daily lives. Smart garment technologies are incorporated into sportswear applications to enhance the well-being and performance of athletes. Smart garments applications in the sports sector are increasing, and the variety of smart garment applications available in the literature is overwhelming. Therefore, it is essential to compare the vast array of technologies incorporated in smart garments for athletes to understand the knowledge gaps for future studies. The protocol paper aims to examine the smart garments used in the sports domain to enhance the health and well-being of athletes.

METHODS AND ANALYSIS

Relevant studies will be retrieved using predefined search terms from Scopus, Web of Science, Science Direct, PubMed and IEEE Xplore. The retrieved articles will be eliminated in two phases: title and abstract screening and full-text screening. The included articles will be primary studies published in the English language within the last 10 years. Subsequently, the included articles will be further studied to extract data using a data extraction form. The extracted data will undergo a thematic analysis. Also, quantitative analysis will be carried out using descriptive statistics.

ETHICS AND DISSEMINATION

The results of this review will provide a comprehensive understanding of smart garment concepts used in the sports domain. The findings of this scoping review will be shared through a journal publication and a conference presentation. Ethical approval is not needed for this scoping review.

PROTOCOL REGISTRATION NUMBER

DOI 10.17605/OSF.IO/34MF2 (https://osf.io/34mf2).

Association Among Dyskinesia of the Lumbar Spine Segment, Inclination Angle of the Lumbosacral Spine, and Low Back Pain in Young Athletes: A Predictive Correlational Study

OBJECTIVE

This predictive correlational study aimed to investigate the association among low back pain (LBP), dyskinesia of the lumbosacral spine segment (determined by inertial sensors), and inclination angles: the inclination angle of the lumbosacral spine (alpha), the inclination angle of the thoracolumbar spine (beta), and the inclination angle of the upper thoracic section (gamma). Our hypothesis was that young athletes with LBP had a particular dyskinesia: nonphysiological movements of the lumbosacral segment of the spine.

METHODS

The study group consisted of 108 young athletes aged 10 to 16 years (male/female 44%/56%; 12.3 ± 1.8 years; 160.1 ± 12.0 cm; 51.1 ± 13.8 kg; 4.3 ± 2.4 training years; 3.7 ± 2.1 training h/wk). The alpha, beta, and gamma angles were measured with a digital inclinometer. The position of the lumbosacral segment at the maximum extension was determined with the inertial sensors, positioned at the 11th thoracic vertebra (T11), the third lumbar spine vertebra (L3), and the second sacral spine vertebra (S2). The data were analyzed using Student's t tests, tetrachoric correlation coefficients, and logistic regression.

RESULTS

There was a significant statistical difference in alpha angles (t = 9.4, P < .001) and lumbar positions in extension (t = 6.4, P < .001) between groups with LBP and without LBP. The logistic regression indicated that LBP in young athletes was significantly associated with the increased alpha angle and nonphysiological lumbar position in extension measured by a sensor at the third lumbar spine vertebra.

CONCLUSION

There was a strong association among LBP, increased inclination angle of the lumbosacral spine, and dyskinesia of the lumbar spine segment in young athletes.