The effect of power stretchers on occupational injury rates in an urban emergency medical services system.

BACKGROUND: To examine occupational injury rates in a dual-response emergency medical services (EMS) system before and after implementation of a power-lift stretcher system. METHODS: The seasonally-adjusted occupational injury rate was estimated relative to medical call volume (per 1000 calls) and workers (per 100 FTEs) from 2009 to 2019, and stratified by severity (lost-time, healthcare only), role (EMS, FIRE) and type (patient-handling). Power-lift stretchers were adopted between 2013 and 2015. Preinjury versus postinjury rates were compared using binomial tests. Interrupted time series (ITS) analysis was used to estimate the trend and change in injuries related to patient-handling, with occupational illnesses serving as control. RESULTS: Binomial tests revealed varied results, with reductions in the injury rate per 1000 calls (-14.0%) and increases in the rate per 100 FTEs (+14.1%); rates also differed by EMS role and injury severity. ITS analysis demonstrated substantial reductions in patient-handling injuries following implementation of power-lift stretchers, both in the injury rate per 1000 calls (-50.4%) and per 100 FTEs (-46.6%), specifically among individuals deployed on the ambulance. Injury rates were slightly elevated during the winter months (+0.8 per 100 FTEs) and lower during spring (-0.5 per 100 FTEs). CONCLUSIONS: These results support the implementation of power-lift stretchers for injury prevention in EMS systems and demonstrate advantages of ITS analysis when data span long preintervention and postintervention periods.

Perceptions of power-assist devices: interviews with manual wheelchair users.

PURPOSE: The study had three main objectives. (1) To investigate the perceived impact of power-assist devices (PADs) on manual wheelchair (MWC) user mobility. (2) To compare perceptions about different types of PADs. (3) To identify preferred features and design characteristics of PADs. METHODS: Semi-structured interviews were conducted with community-dwelling MWC users aged 31 years and older, with at least 2.5 years of experience using an MWC independently (n = 16). Data were thematically analysed using an inductive approach. RESULTS: Two main themes related to participants' perceptions about the effects of PAD use were identified: (1) "Expanding my world", which illustrated the perceived benefits of using PADs (e.g., gaining a sense of autonomy and access to new environments, maintaining physical health) and (2) "Falling short", which described challenges with PADs (e.g., safety, reliability and portability issues). Participants also identified strengths and limitations of different types of PADs that were mainly related to specific user-device and device-environment interactions as well as various functional characteristics. Moreover, participants outlined their priorities for future PAD design, including improving controllability, customizability and affordability of these devices. CONCLUSIONS: Participants' perceptions about PADs varied across different types of devices and in different contexts. However, PADs were generally perceived as enhancing the capabilities of MWCs. Our findings provide insight into the factors that can be considered when selecting a PAD and can inform the development of future PADs that are better equipped to overcome challenges that MWC users frequently encounter.Implications for RehabilitationPower-assist devices (PADs) for manual wheelchairs (MWCs) have the potential to improve the mobility, community participation and well-being of users.Some of the existing PADs have safety and reliability issues that affect their performance and limit their use by MWC users.The three types of PADs (front-mounted attachments, rear-mounted attachments, powered wheels) offer different types of assistance that can benefit users with various capabilities.

Evaluation of two power assist systems for manual wheelchairs for usability, performance and mobility: a pilot study.

BACKGROUND: Power-assist devices for manual wheelchairs offer benefits, including increased community participation. Several power-assist devices are commercially available, but research on benefits and limitations of devices is limited. OBJECTIVE: To compare the usability, performance, and mobility of two power-assist device systems for manual wheelchairs in indoor and outdoor environments. METHODS: This mixed methods pilot study included 11 volunteers with limited wheelchair experience. Participants tested two different power-assist device configurations: (1) the Batec® and (2) the SmartDrive® + Freewheel®. Indoor & outdoor obstacle courses contained relevant skills from the Wheelchair Skills Test, Power Mobility Community Driving Assessment, and Power Mobility Indoor Driving Assessment. The NASA Task Load Index and System Usability Scale assessed participants' perceptions of cognitive demand and usability. A semi-structured interview was conducted to explore participants' experiences. RESULTS: Substantial differences were found in the NASA Task Load Index, and System Usability Scale scores. Participant interviews and researcher observations revealed each device performed better on some obstacle course elements. Qualitative findings showed a general preference for using the Batec® for long trips outside and off-road terrains, primarily due to the Batec's® perceived better speed control, maximum speed, and simpler braking system. Conversely, the SmartDrive® + Freewheel® was deemed most useful indoors and in tight spaces; due to a smaller wheelchair footprint, better turning radius, and increased device portability. CONCLUSION: Further studies are required to understand the usability, performance, and mobility of power-assist devices. Moving forward, these findings will inform end users and occupational therapists when procuring manual wheelchair power-assist devices.Implications for rehabilitationPower-assist devices (PADs) for manual wheelchairs increase the potential for community participation.Qualitative findings showed a general preference for using the Batec® for long trips outside and for off-road terrains, primarily due to the Batec's® perceived better speed control, maximum speed, and simpler braking system.The SmartDrive® + Freewheel® was deemed most useful indoors and in tight spaces; due to a smaller wheelchair footprint, better turning radius, and increased device portability.Increasing knowledge and research about PADs will support development of alternative options for manual or power wheelchairs users. PADs may allow manual wheelchair users (MWC) to delay moving to a power wheelchair (PWC), potentially reducing the perceived stigma associated with transitioning to a power wheelchair and impacting health outcomes.

Effects of the SmartDrive on mobility, activity, and shoulder pain among manual wheelchair users with spinal cord injury - a prospective long-term cohort pilot study.

PURPOSE: to investigate long-term effects of SmartDrive on mobility, everyday activity, and shoulder pain among spinal cord injured manual wheelchairs users. MATERIAL AND METHODS: A prospective pilot intervention study was conducted at Spinalis/Aleris Rehab Station, Sweden. Participants were consecutively invited when evaluated for SmartDrive prescription. Assessments were done at baseline, intervention (use of SmartDrive), and after six months. A smartwatch registered wheelchair utilization including push intensity and pushes/day. Wheelchair Outcome Measure, pain rating instruments including Wheelchair User's Shoulder Pain Index, a wheelchair test, and semi-structured interviews were used. Descriptive statistics and content analysis approach were used. RESULTS: Twenty-five persons were screened, six of 14 included completed the study. Drop-out reasons were not related to SmartDrive for five of the eight persons. After intervention, there was a tendency of decreased pain (median (IQR) 5/10 (2.6-6.6) vs 2.5 (2-3.2). All participants reported increased satisfaction of performance when "taking a walk", from median (IQR) 45/100 (27-70) at baseline to 95 (80-100) at 6 months. Two persons who could not ascend a slope at baseline could manage using the SmartDrive. Interviews revealed that the in general positive response persisted at six months. Also, with the SmartDrive the participants could go out despite pain, providing a sense of freedom and independence. Three incidents were reported. CONCLUSION: This long-term pilot study indicates that a SmartDrive might be a valuable assistive device to promote mobility despite of shoulder pain. All participants considered it easy to use and experienced increased independence, however skills training and follow-ups are necessary. IMPLICATIONS FOR REHABILITATIONA Rear Drive Power Assist Device (RD-PAD) could increase satisfaction with self-selected activities.A RD-PAD could increase functional mobility by facilitating propelling longer distances and steeper slopes.A RD-PAD could improve perseverance of daily activities in spite of shoulder pain.A RD-PAD could be a valuable assistive aid for persons with paraplegia with different level of wheelchair skills but with good self-awareness regarding their abilities.Thorough assessment of initial wheelchair skills, training, and follow-up are important to enhance safety and maximize performance when using the RD-PAD.

A carbon nanotubes based in situ multifunctional power assist system for restoring failed heart function.

BACKGROUND: End-stage heart failure is a major risk of mortality. The conductive super-aligned carbon nanotubes sheets (SA-CNTs) has been applied to restore the structure and function of injured myocardium through tissue engineering, and developed as efficient cardiac pacing electrodes. However, the interfacial interaction between SA-CNTs and the surface cells is unclear, and it remains challenge to restore the diminished contraction for a seriously damaged heart. RESULTS: A concept of a multifunctional power assist system (MPS) capable of multipoint pacing and contraction assisting is proposed. This device is designed to work with the host heart and does not contact blood, thus avoiding long-term anticoagulation required in current therapies. Pacing electrode constructed by SA--CNTs promotes the epithelial-mesenchymal transition and directs the migration of pro-regenerative epicardial cells. Meanwhile, the power assist unit reveals an excellent frequency response to alternating voltage, with natural heart mimicked systolic/diastolic amplitudes. Moreover, this system exhibits an excellent pacing when attached to the surface of a rabbit heart, and presents nice biocompatibility in both in vitro and in vivo evaluation. CONCLUSIONS: This MPS provides a promising non-blood contact strategy to restore in situ the normal blood-pumping function of a failed heart.

sEMG-signal and IMU sensor-based gait sub-phase detection and prediction using a user-adaptive classifier.

This paper presents a gait sub-phase detection and prediction approach using surface electromyogram (sEMG) signals, pressure sensors, and the knee angle for a lower-limb power-assist robot. Pattern recognition and machine learning models using sEMG signals have several inherent problems for gait sub-phase detection. These problems are due to recognition delay, lack of consideration for the unique characteristics of sEMG signals based on the subject, and meaningless features. To solve these problems, we propose a new labeling technique based on the heel and toe, a muscle and feature selection, a user-adaptive classifier using a weighted voting technique to achieve gait sub-phase detection, and a gait sub-phase prediction technique using interpolation. Experimental results show that the average accuracies of the proposed labeling, the muscle and feature selection, and the user-adaptive classifier using weighted voting are 7%, 12%, and 17% better, respectively, than the existing methods using physical sensors. Results also show that the average prediction time of the proposed method is 80% faster than the existing methods.

Comparison of energy efficiency between Wearable Power-Assist Locomotor (WPAL) and two types of knee-ankle-foot orthoses with a medial single hip joint (MSH-KAFO).

OBJECTIVE: To compare the energy efficiency of Wearable Power-Assist Locomotor (WPAL) with conventional knee-ankle-foot orthoses (MSH-KAFO) such as Hip and Ankle Linked Orthosis (HALO) or Primewalk. STUDY DESIGN: Cross over case-series. SETTING: Chubu Rosai Hospital, Aichi, Japan, which is affiliated with the Japan Organization of Occupational Health and Safety. METHODS: Six patients were trained with MSH-KAFO (either HALO or Primewalk) and WPAL. They underwent 6-minute walk tests with each orthosis. Energy efficiency was estimated using physiological cost index (PCI) as well as heart rate (HR) and modified Borg score. Trial energy efficiency with MSH-KAFO was compared with WPAL to assess if differences in PCI became greater between MSH-KAFO and WPAL as time goes on during the 6-minute walk. Spearman correlation coefficient of time (range: 0.5-6.0 minutes) with the difference was calculated. The same statistical procedures were repeated for HR and modified Borg score. RESULTS: Greater energy efficiency, representing a lower gait demand, was observed in trials with WPAL compared with MSH-KAFO (Spearman correlation coefficients for PCI, HR and modified Borg were 0.93, 0.90 and 0.97, respectively, all P < 0.0001). CONCLUSIONS: WPAL is a practical and energy efficient type of robotics that may be used by patients with paraplegia.

Cognition-based variable admittance control for active compliance in flexible manipulation of heavy objects with a power-assist robotic system.

In the first step, a 1-DOF power-assist robotic system (PARS) is developed for lifting lightweight objects. Dynamics for human-robot co-manipulation of objects is derived that considers human cognition (weight perception). Then, admittance control with position feedback and velocity controller is derived using weight perception-based dynamics. Human subjects lift an object with the PARS, and HRI (human-robot interaction) and system characteristics are analyzed. A comprehensive scheme is developed to evaluate the HRI and performance. HRI is expressed in terms of physical HRI (maneuverability, motion, safety, stability, naturalness) and cognitive HRI (workload, trust), and performance is expressed in terms of manipulation efficiency and precision. To follow the guidance of ISO/TS 15066, hazard analysis and risk assessment are conducted. A constrained optimization algorithm is proposed to determine the values of the control parameters that produce optimum HRI and performance with lowest risk. Results show that consideration of weight perception in dynamics and control helps achieve optimum HRI and performance for a set of hard constraints. In the second step, a weight perception-based novel variable admittance control scheme is proposed as an active compliance to the system, which enhances the physical HRI, trust, precision and efficiency by 53.05%, 46.78%, 3.84% and 4.98%, respectively, and reduces workload by 35.38% and thus helps achieve optimum HRI and performance for a set of soft constraints. The risk reduces due to the active compliance. Then, effectiveness of the optimization and control algorithms is validated using a multi-DOF PARS for manipulating heavy objects, and intuitive and natural HRI and performance for power-assisted heavy object manipulation are achieved through calibrating HRI and performance with that for manipulation of lightweight object.