Development and validation of a wheelchair caster testing protocol

The majority of wheelchairs delivered in less-resourced settings fail prematurely. This issue has been recognized by the WHO Guidelines that recommend product testing based on field conditions to evaluate and improve wheelchair quality. This work is motivated from WHO’s recommendation and this is first scientific study investigating inclusion of environmental conditions in wheelchair testing. The goals of this work were to develop a testing protocol for wheelchair casters based on field conditions, evaluate the impact of environmental testing factors on quality and make appropriate recommendations for wheelchair testing based on study outcomes. In this study, an evidence-based approach was followed in which wheelchair testing evidence, expert advice, and field evidence were continually triangulated to inform the testing protocol development. A literature review (Chapter 1) was carried out and expert advice was sought to generate a list of testing methods with environmental factors based on outdoor failures. Caster system failure was identified as a key testing gap that poses significant safety risks to the wheelchair users. Development of a caster testing equipment (Chapter 2) and a caster failure checklist (Chapter 3) was carried out through an iterative design and review approach. The checklist was distributed for collecting failure data following psychometric evaluation and revisions. Testing factors of shock, corrosion and abrasion were validated to respective field exposures and caster testing was conducted (Chapter 4). Environmental factors impacted the durability of 25% caster models and altered failure modes for 75% models. Two-thirds of the altered failure modes have significant risk of causing injuries to users and wheelchair failures. About 73% of the testing failures matched with the most common failure modes experienced in the field. Based on study findings, environmental factors strongly influence both the time-to-failure and failure mode for caster models. We recommend that environmental exposure need to be considered as part of wheelchair testing protocols to help improve the external validity of the testing, which will ultimately improve the safety and reliability of the device. These recommendations are discussed along with caster design recommendations and suggestions for future work in Chapter 5

ISWP Caster Test Version 2.2

This document contains the assembly instructions, electrical wiring information, component manuals, bill of materials, and part drawings required for building the ISWP Caster Test equipment

Design Considerations for Wheelchairs Used in Adverse Conditions

This document was created to guide wheelchair designers, manufacturers, providers, users and their caregivers on design considerations for wheelchairs used in adverse environments, especially those encountered in less-resourced areas. The need for this document was identified as a high priority by the Standards Working Group (SWG) of the International Society for Wheelchair Professionals. The SWG noted that the WHO Guidelines on the Provision of Manual Wheelchairs for Less Resourced Settings provided the general guidance for the design and production of appropriate wheelchairs but lacked detailed information stakeholders need to avoid the common pitfalls for designing wheelchairs where resources are limited and conditions are adverse. A subcommittee of the SWG was formed to draft the document, and the SWG and external reviewers provided feedback remotely and during an in-person meeting hosted by UCP Wheels for Humanity in 2016

Neutrophil-to-Lymphocyte Ratio: A Biomarker to Monitor the Immune Status of Astronauts

A comprehensive understanding of spaceflight factors involved in immune dysfunction and the evaluation of biomarkers to assess in-flight astronaut health are essential goals for NASA. An elevated neutrophil-to-lymphocyte ratio (NLR) is a potential biomarker candidate, as leukocyte differentials are altered during spaceflight. In the reduced gravity environment of space, rodents and astronauts displayed elevated NLR and granulocyte-to-lymphocyte ratios (GLR), respectively. To simulate microgravity using two well-established ground-based models, we cultured human whole blood-leukocytes in high-aspect rotating wall vessels (HARV-RWV) and used hindlimb unloaded (HU) mice. Both HARV-RWV simulation of leukocytes and HU-exposed mice showed elevated NLR profiles comparable to spaceflight exposed samples. To assess mechanisms involved, we found the simulated microgravity HARV-RWV model resulted in an imbalance of redox processes and activation of myeloperoxidase-producing inflammatory neutrophils, while antioxidant treatment reversed these effects. In the simulated microgravity HU model, mitochondrial catalase-transgenic mice that have reduced oxidative stress responses showed reduced neutrophil counts, NLR, and a dampened release of selective inflammatory cytokines compared to wildtype HU mice, suggesting simulated microgravity induced oxidative stress responses that triggered inflammation. In brief, both spaceflight and simulated microgravity models caused elevated NLR, indicating this as a potential biomarker for future in-flight immune health monitoring

Artificial gravity partially protects space-induced neurological deficits in Drosophila melanogaster

Spaceflight poses risks to the central nervous system (CNS), and understanding neurological responses is important for future missions. We report CNS changes in Drosophila aboard the International Space Station in response to spaceflight microgravity (SFμg) and artificially simulated Earth gravity (SF1g) via inflight centrifugation as a countermeasure. While inflight behavioral analyses of SFμg exhibit increased activity, postflight analysis displays significant climbing defects, highlighting the sensitivity of behavior to altered gravity. Multi-omics analysis shows alterations in metabolic, oxidative stress and synaptic transmission pathways in both SFμg and SF1g; however, neurological changes immediately postflight, including neuronal loss, glial cell count alterations, oxidative damage, and apoptosis, are seen only in SFμg. Additionally, progressive neuronal loss and a glial phenotype in SF1g and SFμg brains, with pronounced phenotypes in SFμg, are seen upon acclimation to Earth conditions. Overall, our results indicate that artificial gravity partially protects the CNS from the adverse effects of spaceflight

Biochemical and molecular genetic analysis of mutant androgen receptors in humans

The major objective of this thesis was to determine the molecular basis of a "ligand-selective" mutant androgen receptor (AR) phenotype. Methyltrienelone (MT), a synthetic androgen, dissociates normally from this receptor but mibolerone (MB), another synthetic androgen, dissociates from it two-fold faster than normal. This mutant receptor was identified within genital skin fibroblasts (GSF) from two unrelated individuals with different degrees of androgen insensitivity (AI). Sequence analysis of the AR gene from both subjects revealed a G to A transition at nt 2969 in exon 6 that alters codon 813 from serine to asparagine (S813N). Transiently expressed hAR.S813N did not reproduce the mutant phenotype in several heterologous cells: COS-1, BHK, CHO or HeLa cells. In contrast, when AR free (R$sp-$) GSF were used as host cells, MB-R.S813N complexes dissociated almost two fold faster than the controls (n = 4) while MT-R.S813N complexes dissociated normally. These results establish the G to A transition at nt 2969 as the cause of the ligand-selective phenotype. Such host-cell restricted expression of the mutant dissociation rate points to cell-specific factors that can suppress abnormal dissociation of A-R complexes. Host cell-restricted expression of the abnormal dissociation rates has also been observed for two other transiently expressed mutant AR, hAR.V865L and hAR.R839H (n = 3).Expansion of the glutamine (gln) tract within the N-terminus of the AR causes spinal bulbar muscular atrophy (SBMA), a disease of motor neurons, but the mechanism of this neuropathology is unknown. To determine the effect of gln-tract expansion upon AR function, SBMA-associated mutant AR was transiently expressed and characterized in COS-1 cells. The androgen-binding parameters of the mutant receptor were normal, but it had decreased transactivation competence (50-66% of normal; n = 3). This abnormal transregulatory function may account for the expression of traits associated with minimal androgen insensitivity (MAI) that are variably expressed in the SBMA patients

Development of wheelchair caster testing equipment and preliminary testing of caster models

Background: Because of the adverse environmental conditions present in less-resourced environments (LREs), the World Health Organization (WHO) has recommended that specialised wheelchair test methods may need to be developed to support product quality standards in these environments. A group of experts identified caster test methods as a high priority because of their common failure in LREs, and the insufficiency of existing test methods described in the International Organization for Standardization (ISO) Wheelchair Testing Standards (ISO 7176). Objectives: To develop and demonstrate the feasibility of a caster system test method. Method: Background literature and expert opinions were collected to identify existing caster test methods, caster failures common in LREs and environmental conditions present in LREs. Several conceptual designs for the caster testing method were developed, and through an iterative process using expert feedback, a final concept and a design were developed and a prototype was fabricated. Feasibility tests were conducted by testing a series of caster systems from wheelchairs used in LREs, and failure modes were recorded and compared to anecdotal reports about field failures. Results: The new caster testing system was developed and it provides the flexibility to expose caster systems to typical conditions in LREs. Caster failures such as stem bolt fractures, fork fractures, bearing failures and tire cracking occurred during testing trials and are consistent with field failures. Conclusion: The new caster test system has the capability to incorporate necessary test factors that degrade caster quality in LREs. Future work includes developing and validating a testing protocol that results in failure modes common during wheelchair use in LRE

Design and evaluation of a laboratory-based wheelchair castor testing protocol using community data.

Wheelchair castors fail frequently causing physical, social and economic consequences for wheelchair users. These failures occur in spite of established wheelchair test methods and regulations, suggesting that the existing tests may not be sufficient to screen poorly designed castors. An expert stakeholder group, convened by the International Society of Wheelchair Professionals (ISWP), noted castor failures as a high priority and recommended that a new castor testing system should be developed. In a previous study, the effect of shock exposure on castor durability was studied. The current paper extends the previous work and focuses on the development of a castor testing protocol based on shock, corrosion and abrasion exposure data collected in the community. The testing protocol was applied to 8 different castor models tested under four conditions: shock, corrosion + shock, abrasion + shock and abrasion + corrosion + shock. For each model, a total of n = 8 samples were evaluated across the four conditions. Results demonstrate that corrosion and abrasion reduced castor durability between 13% to 100% depending on the model. Importantly, the inclusion of corrosion and abrasion resulted in changes in the failure modes for 75% of the tested models and two-thirds of the altered failure modes are associated with increased risk of injury for wheelchair users. These results suggest that corrosion and abrasion present in the community reduce castor durability, thus supporting their inclusion in the castor testing protocol and potentially other wheelchair standards

Older Wheelchair Users Recommend Age-Friendly Design Improvements to a Wheelchair Maintenance App: Mixed Methods Development Study

BackgroundWheelchair part failures have doubled over the past decade. Preventative wheelchair maintenance reduces wheelchair failures and prevents user consequences. We are developing a smartphone app called WheelTrak, which alerts users when maintenance is required, to encourage maintenance practices and compliance. ObjectiveThis mixed methods study aimed to develop a wheelchair maintenance app using broad stakeholder advice and investigate older adults’ interaction experience with the app and their perceived barriers to and facilitators of maintenance. MethodsInterviews were conducted with stakeholders, including mobility device users, to generate needs statements and app specifications. The app was designed in 2 stages. Stage 1 involved the development of the app according to the specifications and evaluation of the app interface by lead users. Stage 2 included the revision of the app screens and manual functionality testing. Usability testing and semistructured interviews were conducted with older wheelchair and scooter users. The System Usability Scale was used to measure app usability. ResultsInterviews with power and manual wheelchair users (37/57, 65%), wheelchair service providers (15/57, 26%), manufacturers (2/57, 4%), seating and mobility researchers (1/57, 2%), and insurance plan providers (2/57, 4%) informed the needs and specifications of the app technology. The 2-stage development process delivered a fully functional app that met the design specifications. In total, 12 older adults (mean age 74.2, SD 9.1 years; n=10, 83% women; and n=2, 17% men) participated in the usability testing study. Of the 12 participants, 9 (75%) agreed to use WheelTrak for preventative maintenance. WheelTrak scored an average System Usability Scale score of 60.25 (SD 16). Four overarching themes were identified: WheelTrak app improvements, barriers to maintenance, consequences related to mobility device failure, and smart technology use and acceptance. Older adults preferred the simplicity, readability, personalization, and availability of educational resources in the app. Barriers to maintenance pertained to health issues and lack of maintenance knowledge among older adults. Facilitators of maintenance included notification for maintenance, app connectivity with the service provider, reporting of device failure, and the presence of a caregiver for maintenance. ConclusionsThis study highlighted age-friendly design improvements to the app, making it easy to be used and adopted by older wheelchair users. The WheelTrak app has close to average system usability. Additional usability testing will be conducted following app revision in the future

Assistive Technology Makerspaces Promote Capability of Adults with Intellectual and Developmental Disabilities

Makerspaces can engage people with disabilities in the design and development of assistive technology (AT) that can enhance their capabilities to perform new activities and function. However, the adoption of makerspaces in the environments and institutions serving people with disabilities remains challenging. The authors modeled a makerspace training program, an environmental intervention, based on the capability approach framework. This mixed methods study investigates the feasibility of an 8-week program to train adults (n = 5) with intellectual and developmental disabilities (IDD) and staff members (n = 5) at a community services center. Study outcomes were measured using knowledge tests, surveys, QUEST 2.0 and interviews. Results indicate a significant increase in staff’s knowledge (p = 0.035) and familiarity with program topics (p \u3c 0.05). Participants with IDD were highly satisfied with the ease of use, weight and effectiveness of the AT devices they created. Five themes emerged from the thematic analysis of interviews: (1) inclusive environment, (2) freedom and improved Capability for building technology for self or client, (3) multidisciplinary collaboration, (4) interactive program elements, (5) makerspace challenges. Overall, the makerspace training program is a valuable program that empowers people with disabilities and ensures the realization of their right of autonomy to create their own AT