A series of commercially available titanium ultralight wheelchairs were tested using ANSI/RESNA testing procedures, and their durability was compared with previously tested aluminum ultralight wheelchairs and light-weight wheelchairs. Three of each of the following titanium wheelchairs were tested: Invacare-TopEnd, Invacare-A4, Quickie-Ti, and TiLite-ZRA. The Quickie-Ti wheelchairs had the most forward and rearward center of gravity adjustability. All of the titanium wheelchairs passed the forward braking effectiveness test, but two chairs of each model tipped backward before the platform inclining to 7 degree in the rearward braking effectiveness test. All titanium wheelchairs passed the impact strength tests, but two failed in the static strength tests: two Invacare-TopEnd wheelchairs and one Invacare-A4 wheelchair failed due to deformation of the armrest mounting plates, and the handgrips of the TiLite-ZRA wheelchairs slid off the push handles. Two Invacare-A4 and one Invacare-TopEnd successfully completed the double drum and curb drop tests, but the remaining 9 wheelchairs failed prematurely. No significant differences were found in the number of the equivalent cycles or the value among the four models. The titanium ultralight wheelchairs had less equivalent cycles and value than the aluminum ultralight wheelchairs that were tested in a previous study. The failure modes in the static strength tests and the fatigue tests were consistent within the model, and revealed important design issues for each model. Our results suggest that manufacturers need to perform more careful analyses before commercializing new products.

People with Cerebral Palsy (CP) have difficulty using computer pointing devices due to unintentional movement in their upper extremities. Fifty percent of people with CP have impaired arm-hand function which limits their ability to interface with pointing devices and effectively control cursor movement on the computer screen. This thesis involves two studies which utilize an Isometric Joystick in order to access the computer and complete target acquisition tasks. The first study titled Quantification of Cursor Movement of People with Athetoid and Spastic Cerebral Palsy to Improve Target Acquisition, aims to guide real-time digital filter development for people with athetoid and spastic CP for target acquisition tasks. By investigating the cursor movement measures throughout the target acquisition trajectory we gained a better insight as to when and how to compensate for unintentional movement in people with CP. Results showed that both people with athetoid CP and spastic CP have more difficulty hovering over the target than they did moving to the target, indicating that filter development should focus on the hovering portion of the target acquisition task in order to improve target acquisition time. The second study titled Customized Control for People with Athetosis and Dystonia to Improve Computer Access, aims to develop a method to prescribe appropriate switch/scanning control for people with athetosis and dystonia as well as to determine if customized switch/scanning control is more effective in completing icon selection tasks than the proportional isometric control. Results of this study suggest that switch/scanning control could be useful in moving on the most direct path to the target as shown by a significantly smaller percent distance error for customized control as compared to proportional isometric control (F(1,6) = 361.2, p < 0.01).

Current assistive technology (AT) provision efforts in less-resourced environments rely on heuristic methods to monitor and improve service provision, instead of evidence-based practice (EBP) which has become standard in well-resourced regions. To introduce EBP methods, and evaluate the impact of technology on the lives of people with disabilities, we collaborated with clinicians at the Indian Spinal Injuries Centre (ISIC). Two studies were conducted using ISIC quality assurance data collected with our assistance. Based on our experience at ISIC, a third study was performed to investigate the challenges to international AT research, and develop strategies to overcome these challenges. The first study was conducted with individuals receiving new AT from ISIC. The data consisted of a baseline PART survey and 6-month and 12-month follow-ups taken with a majority (92%) outpatient population. Thirteen clients completed all three questionnaires. Results showed trends toward increased community participation and life satisfaction over the 12-month period. ISIC is planning to expand its implementation of the PART survey, perhaps online. The second study was conducted with individuals (69% inpatient) who received new wheelchairs from ISIC. The Wheelchair Skills Test and QUEST were administered before and after personal wheelchair provision. Seven clients completed a full set of pre- and post-tests. Trends toward increased skill completion rates, increased skill attempt rates, and slightly increased safety scores were found. QUEST scores increased in the post-test, bringing scores close to values reported in literature. The third study, conducted using a three-round Delphi method online, involved the participation of 13 experts in AT and rehabilitation research with experience working in low- and middle-income countries. During the first questionnaire round, participants were asked to identify domains of research that they considered the most challenging. In the second round, they were asked to rank and categorize the challenges as being either ethical or logistical, and also to suggest strategies to address them. In the final round, participants were asked to critique each strategy on its efficacy. Topics discussed included local collaboration, appropriate tools and techniques, translation, retention, compensation, and funding. Verifying the efficacy of suggested strategies could be the subject of future research.

Interaction with the surrounding environment is an essential element of ever day life. For individuals with severe motor and communicative disabilities, single switch scanning is used as method to control their environment and communicate. Despite being very slow, it is often the only option for individuals who cannot use other interfaces. The alteration of timing parameters and scanning system configurations impacts the communication rate of those using single switch scanning. The ability to select and recommend an efficient configuration for an individual with a disability is essential. Predictive models could assist in the goal of achieving the best possible match between user and assistive technology device, but consideration of an individuals single switch scanning tendencies has not been included in communication rate prediction models. Modeling software developed as part of this research study utilizes scan settings, switch settings, error tendencies, error correction strategies, and the matrix configuration to calculate and predict a communication rate. Five participants with disabilities who use single switch scanning were recruited for this study. Participants were asked to transcribe sentences using an on-screen keyboard configured with settings used on their own communication devices. The participants error types, frequencies, and correction methods were acquired as well as their text entry rate (TER) during sentence transcription. These individual tendencies and system configuration were used as baseline input parameters to a scanning model application that calculated a TER based upon those parameters. The scanning model was used with the participants tendencies and at least three varied system configurations. Participants were asked to transcribe sentences with these three configurations The predicted TERs of the model were compared to the actual TERs observed during sentence transcription for accuracy. Results showed that prediction were 90% accurate on average. Model TER predictions were less than one character per minute different from observed baseline TER for each participant. Average model predictions for configuration scenarios were less than one character per minute different from observed configuration TER.

A primary objective of the study was to determine the validity of a SenseWear (SW) activity monitor (AM) in assessing Energy Expenditure (EE) of manual wheelchair users with spinal cord Injury (SCI) while resting and performing three types of physical activities including wheelchair propulsion, arm-ergometer exercise, and deskwork. A secondary objective of the study was to build and validate a new EE prediction model for a SW AM for the physical activities performed in the study. A tertiary objective was to examine the relationship between the criterion EE and three activity monitors including the ActiGraph, the RT3 on arm, and RT3 on waist. Ten manual wheelchair users with SCI were recruited to participate in this pilot study. The results indicate that EE estimated by SenseWear AM with the default EE equationfor resting was close (0.2%) to the criterion EE in manual wheelchair users with SCI. However, the SW AM overestimated EE during deskwork, wheelchair propulsion and arm-ergometry exercise by 6.5%, 105% and 32%, respectively. From the investigation, we found that the EE estimated by SW AM using the new regression equation model significantly improved its performance in manual wheelchair users with SCI. The Intraclass Correlation Coefficient of EE estimated by SW using new prediction equation and the criterion EE were excellent (0.90) and moderate (0.74) with percent errors reduced to 17.4% and 7.0% for wheelchair propulsion and arm-ergometry exercise, respectively. The new prediction equation for SW AM was able to differentiate and discriminate (sensitive)EE estimation in physical activities like wheelchair propulsion and arm-ergometer exercises in manual wheelchair users with SCI indicating that it has a potential to be used in manual wheelchair users with SCI. In addition, the variance explained by RT3 (R2 = 0.68, p<0.001) on arm and the ActiGraph (R2 = 0.59, p<0.001) on the wrist wrist indicate that AMs placed on an arm or wrist may be able to better predict EE compared to the AM on the waist.

The Functional Mobility Assessment (FMA) instrument is a self-report outcome tool, designed to measure the effectiveness of Wheeled Mobility and Seating (WMS) interventions for people with disabilities (PWD). To describe the psychometric properties of the FMAs test-retest reliability, a repeated-measures cohort study was conducted. The specific aims of the study included examining the test-retest reliability of the FMA and determining to what extent each self-reported performance item remained stable when clients responded twice to the same questions over a time period of no less than one week and no more than three weeks. Participants were recruited from the University of Pittsburgh Medical Centers (UPMC) Center for Assistive Technology (CAT). The study sample involved 20 participants who were non-wheelchair or scooter users but in the process of being evaluated for a device (Non-WMS users) and 21 participants who were being evaluated for a replacement device (Existing WMS users). These 41 participants completed an initial FMA questionnaire. After obtaining the initial assessment, the FMA was administered a second time, within 7-21 days. Intra-class correlation coefficients (ICC) were computed to determine agreement between the two scores. Test-retest reliability scores for all items and participants were above the acceptable value of > 0.80 for a clinical assessment tool, except Health Needs and Reach for the Non-WMS users, and Transfers and Carry out daily routine for Existing WMS users. Existing WMS users had higher total scores (greater satisfaction) on the FMA than Non-WMS users. Results indicate that the FMA was a reliable and stable tool for assessing satisfaction of individuals who use or need WMS interventions. Future studies should include larger samples and recruit participants from multiple sites.

While technological developments over the past several decades have greatly enhanced the lives of people with mobility impairments, between 10 and 40 percent of clients who desired powered mobility found it very difficult to operate electric powered wheelchairs (EPWs) safely because of sensory impairments, poor motor function, or cognitive deficits [1]. The aim of this research is to improve control of personalized mobility for those with multiple sclerosis (MS) by examining isometric and movement joystick interfaces with customizable algorithms. A variable compliance joystick (VCJ) with tuning software was designed and built to provide a single platform for isometric and movement, or compliant, interfaces with enhanced programming capabilities. The VCJ with three different algorithms (basic, personalized, personalized with fatigue adaptation) was evaluated with four subjects with MS (mean age 58.7±5.0 yrs; years since diagnosis 28.2±16.1 yrs) in a virtual environment. A randomized, two-group, repeated-measures experimental design was used, where two subjects used the VCJ in isometric mode and two in compliant mode. While still too early to draw conclusions about the performance of the joystick interfaces and algorithms, the VCJ was a functional platform for collecting information. Inspection of the data shows that the learning curve may be long for this system. Also, while subjects may have low trial times, low times could be related to more deviation from the target path.

When an electric powered wheelchair (EPW) user leaves the confines of their home and ventures into the outdoors, they are confronted with a wide variety of terrain and driving conditions. Very little research has been done in trying to understand the difficulties EPW users face when driving outdoors. The first section describes a focus group study of 31 EPW users with the objective of assessing EPW users comfort level when driving in various outdoor conditions. Questionnaire and focus group transcripts showed that the EPW users top concerns were slipping, getting stuck, and tipping. The driving conditions most avoided were in the general themes of soft surfaces, angled surfaces, and adverse conditions. The second section presents in detail the electronic and mechanical design of an advanced controller for an EPW. A single board computer provides the computational power and storage space needed to execute normal operations, complex safety algorithms, and extensive data logging. Sensors provide feedback on velocity and inertia. A rugged aluminum enclosure protects the electronics. The advanced controller is used to research better ways to provide safety and customization for the EPW user. The outcome of this project as a whole was to demonstrate what can be done with an EPW to enhance the mobility and safety of its occupant.

As prevalence of wheelchair usage has increased, wheelchair manufactures are required to provide more and better wheelchairs because of secondary injuries such as pressure sores and repetitive strain injuries. Better qualified wheelchairs provide more adjustment, so wheelchair components have been developed to provide that adjustment. Among the wheelchair components, a backrest is one of critical components of the wheelchair due to the importance of seating position and appropriate trunk support. The Lightweight Durable Adjustable Composite (LWDAC) Backrest Mounting project consisted of three design iterations, prototypes, durability testing, and user evaluation. The backrest mounting is adaptable to most ultralight manual wheelchairs. The backrest is designed with features including height, width and backrest angle adjustment. The angle adjustment adds adjustability and flexibility to a rigid backrest and can be operated with only one hand, without high strength or dexterous manipulation. The LWDAC was tested with ANSI/RESNA durability and fatigue test standards and passed impact test, static stability test and durability test, but not fatigue test. This study also included focus groups to gather user and clinician feedback regarding backrest characteristics. The backrest had overall positive response from participants. The participants agreed the backrest mounting can be operated with one hand, felt comfort when seated, and wheelchair users were interested in purchasing the backrest and clinicians indicated they would recommend the LWDAC backrest.

Lateral ankle sprains are a common injury among all levels of athletic competition and can lead to the development of functional ankle instability (FAI). Individuals with FAI often display postural stability deficits. Numerous ankle questionnaires have been developed to classify subjects with FAI; however, the relationship between ankle questionnaires and postural stability is limited and warrants investigation. The primary purpose of this study was to compare measures of static and dynamic postural stability between FAI and healthy controls. The secondary purpose was to identify the relationship between ankle questionnaires and postural stability in FAI subjects. A total of 24 recreationally active subjects, 12 FAI and 12 healthy controls, between the ages of 18-35 were recruited to participate in this study. Static postural stability was assessed during eyes open and eyes closed single-leg stance. Dynamic postural stability was assessed during single-leg jump landings in the anterior and lateral directions. The ankle questionnaires included the Functional Ankle Disability Index, Ankle Instability Instrument, Ankle Joint Functional Assessment Tool, and Cumberland Ankle Instability Tool. Demographic, postural stability and questionnaire variables were compared using independent samples t-tests. A series of Pearson correlation coefficients were computed to determine the relationship between ankle questionnaires and measures of static and dynamic postural stability. The FAI subjects demonstrated worse (greater perceived symptoms of functional instability) scores on the Functional Ankle Disability Index-Sport, Ankle Instability Instrument, Ankle Joint Functional Assessment Tool, and Cumberland Ankle Instability Tool than the healthy controls. Additionally, FAI subjects demonstrated worse (higher) scores for the medial/lateral ground reaction force standard deviation during eyes closed single-leg stance, vertical stability index, and DPSI during anterior and lateral jumps. Significant correlations were observed between the medial lateral stability index and Ankle Joint Functional Assessment Tool and Cumberland Ankle Instability Tool during lateral jumps. The results of the study demonstrate FAI subjects have static and dynamic postural stability deficits compared to healthy controls. Additionally, the ankle questionnaires were poorly correlated with static and dynamic postural stability suggesting the ankle questionnaires may be inadequate at detecting postural stability deficits in FAI subjects.