Participatory design and validation of mobility enhancement robotic wheelchair

INTRODUCTION The electric powered wheelchair (EPW) is an essential mobility device for people who have limited to no upper- and/or lower-limb movement, such as those diagnosed with spinal cord injury, cerebral palsy, amyotrophic lateral sclerosis, or muscular dystrophy [1-6]. In the United States, people with disabilities typically receive their EPWs through private health insurance, Medicaid, Medicare, vocational rehabilitation, or the Veterans Health Administration [7]. With the exception of vocational rehabilitation and the Veterans Health Administration, these funding sources do not provide funding for EPWs with capabilities that are not necessary for use within the home, such as speeds greater than 6 mph, climbing curbs greater than 3 in., and having a range of 16 mi per charge because they do not meet the coverage criteria outlined in the National Coverage Determination for Mobility Assistive Equipment and the Local Coverage Determination for Power Mobility Devices developed for Medicare [8-9]. EPWs that meet the coverage criteria are designed for indoor usage. As a result, they often lack stability and cause an increase in safety concerns when used outside of the home, especially over uneven terrain. If users need a mobility device inside of their home, they would also need one when they leave their home. Thus, many users must also use their EPW when going to work, doctor's appointments, the grocery store, or a friend's house. Unfortunately, when EPW users venture into the outdoor environment, they may encounter conditions or obstacles that may lead to them becoming stuck or tipping over their wheelchair, causing serious injury or death [10]. Such conditions may include uneven terrain, steep slopes, slippery surfaces, cross slopes, and architectural obstacles such as curbs and steps [11-12]. According to the 2010 U.S. Census, 3.6 million people aged 15 yr and older used a wheelchair [13], of which an estimated 15 percent, or 540,000, use an EPW [14]. The number of EPW users is expected to increase due to the aging baby boomer population and returning troops from the Afghanistan and Iraq wars. As a result, the number of accidents is also expected to rise. One study found that most common accidents were caused by loss of traction, being immobilized, or loss of stability [11]. Another study found that 87.8 percent of 95 participants had experienced a tip or fall up to 3 yr prior to participating in the study [15]. Therefore, the objectives of this project were to understand the conditions and barriers EPW users find difficult to drive in/over in the outdoor environment (phase I), create a computer-aided design (CAD) prototype of an EPW with advanced features that increase the users' safety and ease navigation when encountering such conditions and barriers (phase II), and validate the newly designed EPW and its advanced features by gathering further input from EPW users (phase III). METHODS Phase I Users of EPWs rely heavily on their mobility devices to transport them to where they need to be as safely and independently as possible. Unfortunately, there are instances in which they may encounter hazardous terrain or architectural barriers. In order to gain a deeper understanding of the conditions EPW users encounter, a research study was performed in which active wheelchair users were asked to complete a questionnaire about their demographic information, type of EPW used, and driving experience in 23 different driving conditions. The 23 conditions were identified based on feedback from experienced EPW users and licensed professionals in wheelchair provision. Additionally, a focus group discussion took place where they were asked to further discuss difficult driving scenarios they had encountered. The interviews and focus groups were held between September 2008 and July 2009. Participants Ethical approval for this study was obtained from the institutional review board of the Department of Veterans Affairs Pittsburgh Healthcare System, and all participants were asked to provide informed consent prior to enrollment in the study. …