Manual wheelchairs are great! But…

Long term manual wheelchair (MW) self-propulsion causes prevalent problems such as shoulder pain due to subacromial impingement (42-66% incidence), wrist pain due to carpal tunnel syndrome (49-73% incidence), and general upper limbs muscular pain. The current approach to prevent such injuries is: appropriate and timely provision of wheelchair, and skills training. For long term MW users that already have injuries and pain, the current treatment approach is: physiotherapy, pain killers, surgery or switching to an electric wheelchair. Power assist devices use motors that drive the wheelchair back wheels to help the users self-propel with demonstrated reduction of effort, pain and injuries. We interviewed nine MW users regarding their needs and expectations on adding assistance for propelling their wheelchairs. We also reviewed the power assist devices available. We have found that although MW users understood the benefits of using powered propelling assistant devices, the technology is not widely used due to lack of awareness and unaffordability. A high quality, affordable, open source, fully mechanical and lightweight assist device is needed. While waiting for researchers to create such high quality affordable device, we recommend MW users to use tricycles or lever drive propulsion, when possible, instead of the standard inefficient handrim propulsion

Supporting the Voice of People with Disabilities in Kenya, Uganda and Jordan

Research methods need to be adapted to the cultural context and traditions with which participants are familiar. Limited work has been attempted to explore ways to engage people with disabilities in low resource settings. In this paper we present methods used in two research projects that engage and actively support the voice of people with disabilities living in low resource settings. We discuss which methods have worked well and which not, with recommendations based on our experience and the research results

Individuality over function: the role of technology in disability identity

When designing or investigating technology use among people with disabilities, researchers often overstate the importance of functional aspects at the expenses of identity. We present three case studies that showcase how people with disabilities use, or aspire to use, technology to advertise, reframe or hide their identities

Two sides of the same coin: accessibility practices and neurodivergent users' experience of extended reality

Purpose: This paper explores the accessibility barriers faced by neurodivergent individuals regarding the use of Extended Reality (XR) technologies and the difficulties faced by developers in creating neurodivergent inclusive XR experiences. Design/methodology/approach: The authors carried out a survey with neurodivergent participants, and a series of semi-structured interviews with neurodivergent adults and XR developers. Findings: Neurodivergent individuals experience sensory overload when using XR technologies; these negative experiences are exacerbated by excessive multisensory stimulation. Allowing for the customization of sensory settings was seen as the only way to potentially limit negative experiences. The authors found that XR developers lacked awareness of accessibility requirements and struggled to integrate them in current software development practices. Social implications: Accessibility understanding regarding neurodivergence is increasingly available and the time has come to bring computing and information services within the reach of all neurodivergent individuals. The power in the design of XR, which is crucial, is decentralized from neurotypical XR developing practices to avoid artificial barriers that decrease the quality of life. Originality/value: There is a lack of studies exploring how neurodivergent individuals experience XR considering their different sensory processing patterns. There is also no research exploring XR developers' awareness of accessibility needs of neurodivergent individuals. This paper presents an account of the challenges faced by neurodivergent XR users, the difficulties faced by XR developers to integrate neurodivergent accessibility requirements, and proposes specific strategies to overcome challenges

Muscular Activity and Physical Interaction Forces during Lower Limb Exoskeleton Use

Spinal cord injury (SCI) typically manifests with a loss of sensorimotor control of the lower limbs. In order to overcome som e of the disadvantages of chronic wheelchair use by such patients, robotic exoskeletons are an emerging technology that has the pot ential to transform the lives of patients. However, there are a number of points of contact between the robot and the user, which lead to interaction forces. In a recent study, we have shown that peak interaction forces are particularly prominent at the an terior aspect of the right leg. This study uses a similar experimental protocol with additional EMG (electromyography) analysis to examine whether such interaction forces are due to t he muscular activity of the participant or the movement of the exoskeleto n itself. Interestingly, we found that that peak forces preceded peak EMG activity. This study did not find a significant correlation between EMG activity and force data, which would indicate that the interaction f orces can largely be attributed to the mov ement of the exoskeleton itself. However, we also report significantly higher correlation coefficients in muscle/force pairs located at the anterior aspect of the right leg. In our previous research, we have shown peak interaction forces at the same locati ons, which suggests that muscular activity of the participant makes a more significant contribution to the interaction forces at these locations. The findings of this study are of significance for incomplete SCI patients, for whom EMG activity may provide an important input to an intuitive control schema

Instrumented elbow orthosis

Although work on exoskeleton technology started as early as in the 1960’s, it is mostly recognized and used as devices to aid in the rehabilitation process and for military purposes. The use of wearable and portative exoskeleton technology for functional compensation is less well understood for the upper limbs in comparison with the lower limbs. A review of current upper limb exoskeleton technology suggests that there is limited attention to the interaction between the exoskeleton and the human. In order to control or compensate movement, exoskeletons transfer forces through a physical coupling between the device and the human limb (exoskeleton-human interface). This exoskeleton-human interface is a physical coupling that requires the consideration of optimal and safe force transfer (magnitude, direction and locations) as well as user comfort; considerations that have been overlooked by current exoskeleton technology. Before implementing a highly specialized electronic control system between the user and exoskeleton, it is necessary to design a truly wearable, safe and comfortable mechanical structure. The aims of this study are to modify a commercial elbow orthesis by instrumenting it with a control system and force sensors in order to measure the following parameters: dynamic stiffness and pressure between the orthosis and the human skin. This instrumented orthosis is further controlled by the user through a mouth switch. The instrumented orthosis is employed to monitor forces and stiffness during activities of daily life which involve self-care and domestic life for a fully abled person. Upper limb exoskeleton designers could use this data to fabricate technology that exerts forces that are safe and within what the end user considers comfortable. This modified orthosis will be used in a future study in individuals with spinal cord injury from C5 to C8 levels

“But, I Don’t Want/Need a Power Wheelchair”: Toward Accessible Power Assistance for Manual Wheelchairs

Power assist devices help manual wheelchair users to propel their wheelchair thus increasing their independence and reducing the risk of upper limb injuries due to excessive use. These benefits can be invaluable for people that already have upper limb joint pain and reduced muscular strength. However, it is not clear if the way that assistance is provided by such devices is what manual wheelchair users need and expect. 12 manual wheelchair users were interviewed to understand: the situations in which they find it difficult to propel their wheelchairs; situations they considered paramount to have power assistance; their experience or knowledge of power assist devices; and likes and dislikes of commercially available power assist devices. Finally, they were asked to comment on their ideal form factor of a power assist device. Users have suggested improvements of the devices' accessibility and visualized new ways in which they could interact with the technology. These interactions involve "chairable" devices independent from, but not excluding, wearable devices and mobile applications. We have identified the need of monitoring emotions and the need for designing an open source do-it-yourself wheelchair propelling assistance device which we believe is required equally in developed and in developing countries

Characterization of bespoke force sensors for tailored applications

Bespoke force sensors made with active polymer composites are inexpensive, thin and flexible, hence popular in wearable electronics, however their wider application is limited due to the lack of literature studying their voltage response related errors. We present the voltage response characterization of bespoke force sensors made with an active polymer composite, silver coated fabric, stainless steel thread and silver epoxy. Characterization of the effects of static and dynamic loading was completed with a mechanical testing machine. Static tests consisted of loading and unloading at 0.01, 0.1, 0.5 and 1 N/s, and drift tests for 120 minutes up to 10 N every 1 N. Dynamic tests consisted of a sinusoidal load of 5 N ± 1 N applied at 0.05, 0.1 and 0.5 Hz for 60 minutes. The force-voltage relationships were modelled using an exponential function. Maximum mean drift error was observed when applying different static loads for 120 minutes each. Drift error is minimal at 5 s (<1%)and at 60 (< 5%) minutes with loads under 1 N. Maximum hysteresis of 18% was observed at a 1 N/s loading rate. The maximum drift error after one hour of dynamic loading was observed at 0.5 Hz and is minimal (-0.00004%). The cost of fabricating these sensors is very low compared with commercially available options. These sensors can be fabricated in any shape and size with the added advantage of being able to set the location of the electronic connections as desired

Neuroergonomic Assessment of Wheelchair Control Using Mobile fNIRS

For over two centuries, the wheelchair has been one of the most common assistive devices for individuals with locomotor impairments without many modifications. Wheelchair control is a complex motor task that increases both the physical and cognitive workload. New wheelchair interfaces, including Power Assisted devices, can further augment users by reducing the required physical effort, however little is known on the mental effort implications. In this study, we adopted a neuroergonomic approach utilizing mobile and wireless functional near infrared spectroscopy (fNIRS) based brain monitoring of physically active participants. 48 volunteers (30 novice and 18 experienced) self-propelled on a wheelchair with and without a PowerAssist interface in both simple and complex realistic environments. Results indicated that as expected, the complex more difficult environment led to lower task performance complemented by higher prefrontal cortex activity compared to the simple environment. The use of the PowerAssist feature had significantly lower brain activation compared to traditional manual control only for novices. Expertise led to a lower brain activation pattern within the middle frontal gyrus, complemented by performance metrics that involve lower cognitive workload. Results here confirm the potential of the Neuroergonomic approach and that direct neural activity measures can complement and enhance task performance metrics. We conclude that the cognitive workload benefits of PowerAssist are more directed to new users and difficult settings. The approach demonstrated here can be utilized in future studies to enable greater personalization and understanding of mobility interfaces within real-world dynamic environments

Disability Design and Innovation in Low Resource Settings: Addressing Inequality through HCI

Approximately 15% of the world's population has a disability and 80% live in low resource-settings, often in situations of severe social isolation. Technology is often inaccessible or inappropriately designed, hence unable to fully respond to the needs of people with disabilities living in low resource settings. Also lack of awareness of technology contributes to limited access. This workshop will be a call to arms for researchers in HCI to engage with people with disabilities in low resourced settings to understand their needs and design technology that is both accessible and culturally appropriate. We will achieve this through sharing of research experiences, and exploration of challenges encountered when planning HCI4D studies featuring participants with disabilities. Thanks to the contributions of all attendees, we will build a roadmap to support researchers aiming to leverage post-colonial and participatory approaches for the development of accessible and empowering technology with truly global ambitions