Long-term community integration study of an affordable manual standing wheelchair.

PURPOSE: The manual, user-operated Arise Standing Wheelchair (SWC) is the end result of multiple design iterations based on findings and feedback from user trials. The Arise SWC provides standing functionality, outdoor mobility, affordability, and customisability. This paper describes a long-term community integration study of the Arise SWC. METHODS: All participants (N = 8; 7 Male, 1 Female) were persons with spinal cord injuries. During the study period (six months), the participants integrated the Arise SWC into their daily routines. To assess the impact of the Arise SWC on various outcome measures, participants' responses were captured using a Likert-scale questionnaire at the beginning of the study, after 30 days, and after 180 days of Arise SWC usage. RESULTS: The long-term usage of the Arise SWC positively impacted the users' standing performance (ability to stand regularly, stand at different locations, and stand in community settings), productive ability (accessibility to environmental controls and ability to perform overhead reaches), and pathophysiology (spasticity and ability to get proper sleep). Furthermore, all the users were able to independently move using the Arise SWC over even and uneven terrain (some needed minimal assistance over uneven terrain). CONCLUSIONS: Overall, we believe that Arise SWC will benefit eligible users and improve their ability and performance in daily activities.

Arise Standing Wheelchair (SWC) positively impacted users' standing performance, mobility over uneven terrain, ability to transfer between surfaces, and overhead reaches.Arise SWC positively impacted users' overall physical well-being.The study shows that Arise SWC improved the users' overall daily living activities.Arise SWC, an affordable solution, is anticipated to have a global impact, especially on low-income nations.

3D-printed design iteration of a low-tech positive obstacle pushing/gliding wheelchair accessory.

PURPOSE: Steering a wheelchair while navigating through manual doors or against obstacles is challenging for some users. Previously, a low-cost, low-tech accessory made using off-the-shelf components, conventional manufacturing, and 3D-printed fasteners demonstrated the proof-of-concept for uncrossable positive obstacle pushing or gliding. Current work presents the fabrication and testing of an entirely 3D-printed prototype of the accessory. METHODS: The accessory was 3D-printed using ABS (10% fill density) in sections. A finite element stress analysis simulation was performed for the entire accessory. Prototype tests were done with the accessory installed on an unoccupied powered wheelchair against a door and an obstacle with ∼25 N and ∼50 N resistance forces, respectively. RESULTS: The maximum stresses in none of the crucial components exceeded the break strength of ABS. Test results demonstrate the ability and mechanical robustness of the fully 3D-printed accessory to push open manual doors, allowing easy navigation through doors, and to push or glide against obstacles. The current prototype improves over the previous prototype in terms of manufacturability, weight, design, and safety. CONCLUSIONS: To the best of our knowledge, this is the first demonstration of an entirely 3D-printed wheelchair accessory that pushes or glides against uncrossable positive obstacles. Future studies would involve end-user satisfaction assessment and functionality evaluation in different scenarios under clinical supervision. The pushing or gliding ability of the accessory could be beneficial to wheelchair users with neuromuscular disorders or paraplegia.

Low-tech 3D-printed accessory allows wheelchair users to push or glide against doors and other obstacles.Protective nature of the accessory could prove highly beneficial to some wheelchair users (those with diabetic feet).Pushing or gliding ability of the accessory could be beneficial to wheelchair users with neuromuscular disorders or paraplegia.Accessory could reduce wheelchair accidents and falls due to uncrossable positive obstacles.3D printing allows easy prototyping of wheelchair-related assistive technology solutions.

Design of a low-cost, reconfigurable, standing wheelchair with easy and stable sit-stand-sit transition capability.

PURPOSE: Assistive devices like Standing Wheelchairs (SWC) have remained out of reach of the economically underprivileged even before the pandemic-induced financial downturn, and more so now. This paper describes the mechanical design of a manual user-actuated SWC that is cost-effective (equivalent of USD 210 in India, ex-factory) and has special features that minimise user effort and accommodates varying body weights (50-110 kg) and dimensions (1.52-1.83 m height). METHODS: The design includes a six-bar mechanism and spring balancing to optimise user effort during operation. The optimised gas spring incorporates adjustability to minimise each user's force for sit-stand-sit transitions. The handle shape is ergonomically designed using kinematic analysis to provide convenient gripping positions for actuation. The design has been customised based on parametric studies to suit varying body weights. RESULTS: Overall, the SWC design provides standing functionality with ease of operation, safety locks, customisability, affordability, outdoor mobility and is aesthetically pleasing. CONCLUSIONS: Customisability and the low cost of the device would enhance the accessibility of the SWC to a larger group of eligible users.Implications for rehabilitationManual user-operated standing wheelchair design using a six-bar mechanismSpring balancing used to reduce user effort to self-lift to the standing positionKinematic analysis used to determine convenient handle location for user easeCustomisability for wide range of users to ensure correct posture, optimal effortDesign refined through multiple iterations using inputs from users and cliniciansDesign commercialised at an affordable cost, making it accessible to a larger population.

Design journey of an affordable manual standing wheelchair.

PURPOSE: Only 1 in 10 people with disabilities can access assistive devices, underlining the critical need for low-cost assistive products. This paper describes the design evolution of a manual user-operated standing wheelchair (SWC), translating from prototype to product. METHODS: The SWC design has been refined over 5 years through multiple iterations based on comments from user trials. The SWC product, Arise, provides standing functionality, facile outdoor mobility, affordability, customisability, and is aesthetically pleasing. A one-time fitting and training ensure optimal effort for operation, correct posture, and comfortable user experience. The SWC accommodates users of different sizes and body weights (up to 110 kg) and minimises user effort with the use of a gas spring. Incorporating discrete adjustments enables customisation while retaining the advantages of mass manufacturing, which is necessary for ensuring affordability. RESULTS: The SWC has been field-tested and well received by over 100 wheelchair users, and Arise was launched recently by the industry partner. CONCLUSIONS: It should be noted that RESNA cautions on the use of any standing device without medical consultation. Nevertheless, with appropriate dissemination and awareness, it is anticipated that the affordable SWC product, Arise, will immensely benefit the eligible users and make a difference in their quality of life.Implications for RehabilitationProvides standing functionality, outdoor mobility, affordability and customisabilityAccommodates users of different sizes and body weights in a mass-manufacturable designErgonomic design reduces net user effort during sit-to-stand, stand-to-sit activityDesign iterated and refined based on feedback from over 100 user trials.

User experience study of an affordable manual standing wheelchair.

PURPOSE: The manual user-operated Arise Standing Wheelchair (SWC) is the end-result of multiple design iterations based on comments from user trials. The Arise SWC provides standing functionality, outdoor mobility, affordability, and customizability. This paper describes a user experience study of the Arise SWC's pre-commercial version. METHODS: Thirty participants (N = 30, 25 Male, 5 Female) were recruited for the study. All the participants were people with spinal cord injury. The study was conducted over a period of six weeks (five participants per week) within the hospital premises under the supervision of clinical personnel. A 30 min interactive training session involved thirteen activities. During the trial period, the participants were trained to perform twenty-two activities to familiarize themselves with the SWC. The participants were also trained to perform four functional usage activities with the SWC. At the end of the study, participant responses to ten outcome measures were captured using a smiley-based Likert-scale questionnaire. RESULTS: A majority of the participants (93.3%) felt happy when they stood in the SWC. The majority participants (83.3%) preferred the Arise SWC over their current wheelchair. Also, 80% participants anticipated that they could get more work done at home using the standing function of the wheelchair. CONCLUSIONS: A one-time fitting and training ensured optimal effort for the SWC operation, correct posture, and comfortable user experience. With proper dissemination and awareness, it is believed that the Arise SWC will benefit eligible users and improve their quality of life.IMPLICATIONS FOR REHABILITATIONThe Arise wheelchair provides standing functionality, outdoor mobility, affordability, and customizability.Study confirms that incorporating standing functionality can improve the quality of life for wheelchair users.The majority of users were happy, felt safe and expected to do more with the standing functionality.Study results support further testing in real world conditions beyond the hospital setting.

Validation of wearable inertial sensor-based gait analysis system for measurement of spatiotemporal parameters and lower extremity joint kinematics in sagittal plane.

Wearable inertial sensor-based motion analysis systems are promising alternatives to standard camera-based motion capture systems for the measurement of gait parameters and joint kinematics. These wearable sensors, unlike camera-based gold standard systems, find usefulness in outdoor natural environment along with confined indoor laboratory-based environment due to miniature size and wireless data transmission. This study reports validation of our developed (i-Sens) wearable motion analysis system against standard motion capture system. Gait analysis was performed at self-selected speed on non-disabled volunteers in indoor (n = 15) and outdoor (n = 8) environments. Two i-Sens units were placed at the level of knee and hip along with passive markers (for indoor study only) for simultaneous 3D motion capture using a motion capture system. Mean absolute percentage error (MAPE) was computed for spatiotemporal parameters from the i-Sens system versus the motion capture system as a true reference. Mean and standard deviation of kinematic data for a gait cycle were plotted for both systems against normative data. Joint kinematics data were analyzed to compute the root mean squared error (RMSE) and Pearson's correlation coefficient. Kinematic plots indicate a high degree of accuracy of the i-Sens system with the reference system. Excellent positive correlation was observed between the two systems in terms of hip and knee joint angles (Indoor: hip 3.98° ± 1.03°, knee 6.48° ± 1.91°, Outdoor: hip 3.94° ± 0.78°, knee 5.82° ± 0.99°) with low RMSE. Reliability characteristics (defined using standard statistical thresholds of MAPE) of stride length, cadence, walking speed in both outdoor and indoor environment were well within the "Good" category. The i-Sens system has emerged as a potentially cost-effective, valid, accurate, and reliable alternative to expensive, standard motion capture systems for gait analysis. Further clinical trials using the i-Sens system are warranted on participants across different age groups.

Proof-of-concept of a stair-climbing add-on device for wheelchairs.

Motorized designs of stair-climbing wheelchairs available in western countries are heavy and expensive, and hence, unsuitable for developing countries. Manually operated solutions for stair-climbing wheelchairs also tend to be bulky and complex. As stair-climbing is an occasional activity for wheelchair users, having a built-in stair-climbing mechanism results in complexity and redundancy. In this work, an add-on device is envisaged, which requires the wheelchair to be mounted onto the add-on only when stair-climbing is needed. This work developed a Hex-wheel mechanism to address the demerits of the Y-wheel mechanism commonly used in load carriers, as well as to improve usability for stair-climbing. Furthermore, a suitably designed actuation mechanism was applied to the Hex-wheel to enable manual operation. Finally, a prototype of the stair-climbing add-on device was built to validate the developed mechanisms. The force required to operate the device was measured and found to be within 10% of the predicted theoretical value. The novel design provides a solution manually operable by an assistant, which is cost-effective and independent of wheelchair type to improve accessibility in low-resource settings.

Low-cost low-tech obstacle pushing/gliding wheelchair accessory.

Purpose: Some wheelchair users continue to struggle in maneuvering a wheelchair and navigating through manual doors. Several smart wheelchairs and robotic manipulators were developed to minimize such challenges facing disabled people. Disappointingly, a majority of these high-tech solutions are restricted to laboratories and are not extensively available as commercial products. Previously, a low-tech wheelchair accessory (arc-shaped with many wheels) for pushing doors was modelled and simulated. This work demonstrates the fabrication and testing of the first-generation prototype of the accessory.Materials and methods: The accessory has side portions with a straight arrangement of wheels and a front portion with a straight-arc-straight arrangement of wheels. The accessory was fabricated using conventional manufacturing, off-the-shelf components, and 3D printed ABS fasteners. Stress analysis simulations were done for the fasteners that attach the front accessory to the wheelchair frame. The proof-of-concept of the prototype installed onto a powered wheelchair was tested with a door and an obstacle, each with ∼50 N resistance force.Results: Prototype tests demonstrate the ability of the accessory along with the mechanical robustness of the 3D printed fasteners to push open doors allowing easy navigation through doors and to push/glide against obstacles. The accessory is foldable and detachable.Conclusion: The low-cost of the accessory makes it affordable to many users intending to improve their quality of life. The current study provides an engineering perspective of the accessory, and a clinical perspective is crucial. Other potential applications of the wheelchair accessory include use with scooters, walkers and stretchers.Implications for rehabilitationLow-cost, low-tech accessory is foldable and detachable.Accessory is effective for pushing doors and pushing/gliding against obstacles.Protective nature of the front accessory could prove highly beneficial to some wheelchair users.

Modeling and Simulation of Two Wheelchair Accessories for Pushing Doors.

Independent mobility is vital to individuals of all ages, and wheelchairs have proven to be great personal mobility devices. The tasks of opening and navigating through a door are trivial for healthy people, while the same tasks could be difficult for some wheelchair users. A wide range of intelligent wheelchair controllers and systems, robotic arms, or manipulator attachments integrated with wheelchairs have been developed for various applications, including manipulating door knobs. Unfortunately, the intelligent wheelchairs and robotic attachments are not widely available as commercial products. Therefore, the current manuscript presents the modeling and simulation of a novel but simple technology in the form of a passive wheelchair accessory (straight, arm-like with a single wheel, and arc-shaped with multiple wheels) for pushing doors open from a wheelchair. From the simulations using different wheel shapes and sizes, it was found that the arc-shaped accessory could push open the doors faster and with almost half the required force as compared to the arm-like accessory. Also, smaller spherical wheels were found to be best in terms of reaction forces on the wheels. Prototypes based on the arc-shaped accessory design will be manufactured and evaluated for pushing doors open and dodging or gliding other obstacles.

Chondrocyte Behavior on Micropatterns Fabricated Using Layer-by-Layer Lift-Off: Morphological Analysis.

Cell patterning has emerged as an elegant tool in developing cellular arrays, bioreactors, biosensors, and lab-on-chip devices and for use in engineering neotissue for repair or regeneration. In this study, micropatterned surfaces were created using the layer-by-layer lift-off (LbL-LO) method for analyzing canine chondrocytes response to patterned substrates. Five materials were chosen based on our previous studies. These included: poly(dimethyldiallylammonium chloride) (PDDA), poly(ethyleneimine) (PEI), poly(styrene sulfonate) (PSS), collagen, and chondroitin sulfate (CS). The substrates were patterned with these five different materials, in five and ten bilayers, resulting in the following multilayer nanofilm architectures: (PSS/PDDA)5, (PSS/PDDA)10; (CS/PEI)4/CS, (CS/PEI)9/CS; (PSS/PEI)5, (PSS/PEI)10; (PSS/Collagen)5, (PSS/Collagen)10; (PSS/PEI)4/PSS, (PSS/PEI)9/PSS. Cell characterization studies were used to assess the viability, longevity, and cellular response to the configured patterned multilayer architectures. The cumulative cell characterization data suggests that cell viability, longevity, and functionality were enhanced on micropatterned PEI, PSS, collagen, and CS multilayer nanofilms suggesting their possible use in biomedical applications.

Brain slice stimulation using a microfluidic network and standard perfusion chamber.

We have demonstrated the fabrication of a two-level microfluidic device that can be easily integrated with existing electrophysiology setups. The two-level microfluidic device is fabricated using a two-step standard negative resist lithography process. The first level contains microchannels with inlet and outlet ports at each end. The second level contains microscale circular holes located midway of the channel length and centered along with channel width. Passive pumping method is used to pump fluids from the inlet port to the outlet port. The microfluidic device is integrated with off-the-shelf perfusion chambers and allows seamless integration with the electrophysiology setup. The fluids introduced at the inlet ports flow through the microchannels towards the outlet ports and also escape through the circular openings located on top of the microchannels into the bath of the perfusion. Thus the bottom surface of the brain slice placed in the perfusion chamber bath and above the microfluidic device can be exposed with different neurotransmitters. The microscale thickness of the microfluidic device and the transparent nature of the materials [glass coverslip and PDMS (polydimethylsiloxane)] used to make the microfluidic device allow microscopy of the brain slice. The microfluidic device allows modulation (both spatial and temporal) of the chemical stimuli introduced to the brain slice microenvironments.

Fabrication of interdigitated micropatterns of self-assembled polymer nanofilms containing cell-adhesive materials.

Micropatterns of different biomaterials with micro- and nanoscale features and defined spatial arrangement on a single substrate are useful tools for studying cellular-level interactions, and recent reports have highlighted the strong influence of scaffold compliance in determining cell behavior. In this paper, a simple yet versatile and precise patterning technique for the fabrication of interdigitated micropatterns of nanocomposite multilayer coatings on a single substrate is demonstrated through a combination of lithography and layer-by-layer (LbL) assembly processes, termed polymer surface micromachining (PSM). The first nanofilm pattern is constructed using lithography, followed by LbL multilayer assembly and lift-off, and the process is repeated with optical alignment to obtain interdigitated patterns on the same substrate. Thus, the method is analogous to surface micromachining, except that the deposition materials are polymers and biological materials that are used to produce multilayer nanocomposite structures. A key feature of the multilayers is the capability to tune properties such as stiffness by appropriate selection of materials, deposition conditions, and postdeposition treatments. Two- and four-component systems on glass coverslips are presented to demonstrate the versatility of the approach to construct precisely defined, homogeneous nanofilm patterns. In addition, an example of a complex system used as a testbed for in vitro cell adhesion and growth is provided: micropatterns of poly(sodium 4-styrenesulfonate)/poly-L-lysine hydrobromide (PSS/PLL) and secreted phospholipase A(2)/poly(ethyleneimine) (sPLA(2)/PEI) multilayers. The interdigitated square nanofilm array patterns were obtained on a single coverslip with poly(diallyldimethylammonium chloride) (PDDA) as a cell-repellent background. Cell culture experiments show that cortical neurons respond and bind specifically to the sPLA(2) micropatterns in competition with PLL micropatterns. The fabrication and the initial biological results on the nanofilm micropatterns support the usefulness of this technique for use in studies aimed at elucidating important biological structure-function relationships, but the applicability of the fabrication method is much broader and may impact electronics, photonics, and chemical microsystems.

Cell adhesion testing using novel testbeds containing micropatterns of complex nanoengineered multilayer films.

Methods for producing biomaterial patterns with defined spatial distribution micro- and nano-scale features are important for studying the cellular-level interactions, including basic cell-to-material and cell-to-cell communications. This work reports on the fabrication of substrates to study cell adhesion to multicomponent micropatterns of multilayer films by coupling conventional photolithography and LbL techniques, known as the L-LbL technique. Toward this end, substrates with nanofilm micropatterns of two different bio-functionalities have been fabricated for sPLA/sub 2/ and PLL and were used for in vitro cell-culture studies using neurons, which exhibited preferential and high efficiency and selective adhesion to sPLA/sub 2/ nanofilms. These results support the immediate use of multicomponent micropatterns as biological testbeds for basic studies of cells, and provide a basis for further expansions of the fabrication processes to produce scaffolds for precise definition of cell-to-material and cell-to-cell interactions, such that the resulting constructs mimic in vivo cell organization and behavior.