1) The clinical need: An estimated 1.5 million people in the United States use a manual wheelchair. The proportion of the population using wheelchairs increases sharply with age. Four-fifths of wheelchair users in all age groups report some degree of difficulty in at least one activity of daily living. While bathing is the activity most likely to present problems, a majority of wheelchair users also are limited in transferring, toileting, and getting around inside the home.   Self-transfers from a wheelchair are critical to optimizing safe function in the home.  Falls during wheelchair transfer are the most common cause of falls by patients receiving rehabilitation for lower limb amputation.  Tub transfers are consistently identified as one of the most difficult activities in the Functional Independence Measure for individuals after stroke, spinal cord injury and across all disabilities.  Understanding the impact of age, muscle strength and various strategies used to perform these home transfer activities will have a significant impact on mobility in the home and the ability to age in place for persons aging with a disability.
            Of those aged 64 years and under, spinal cord injury (SCI) is the most common diagnosis in manual wheelchair users. Both improved life expectancy and increasing age at injury have resulted in a population that is increasingly experiencing the impact of aging with a disability. One of the most common secondary complaints in the SCI population is shoulder joint pain.  The incidence of shoulder joint pain after SCI is greater than that in the non-disabled population at every age and increases steadily with time post-injury impacting a full 70% of individuals at 20 years post injury.  While increased shoulder joint pathology has been documented extensively in the spinal cord injury population, persons with other primary diagnoses that preclude function of the lower extremities (e.g., lower extremity amputation, poliomyelitis, myelomeningocele, multiple sclerosis) experience a similar course of shoulder pain with prolonged wheelchair use.  Because individuals who use a manual wheelchair are dependent on their upper extremities, shoulder dysfunction and pain can present a devastating loss of independence and decreased quality of life.
            The increased prevalence of shoulder pain in manual wheelchair users has been attributed to the increased weight bearing demands on the upper extremities imposed by wheelchair use, transfers and raises.  In particular, the most strenuous activities and those that provoke the highest pain responses are entering/leaving a car, ascending ramps, heavy lifting with arms and outdoor wheeling.  The biomechanical demands of transfers and, in particular, car transfers have not been investigated as thoroughly as those of wheelchair propulsion.  In order to make recommendations on how to reduce the damaging forces on the shoulders of manual wheelchair users, a complete biomechanical assessment of car transfers is needed to identify the points of highest demand on the shoulder. These recommendations are critical to preserve shoulder function and maintain community mobility for manual wheelchair users aging with and into disability.           

2) Research and Development Activities: The design of this project includes two activities: one primarily research and one dominantly development.  In the research activity, we will gather critical information on the social context of the transfers and barriers to independence from our focus group interactions and video tape recordings (Research Aim 1).  We will document the biomechanical demands on the shoulder joint of various strategies for performing both home (tub, toilet, bed) and car transfers. Additionally we will identify the impact on the shoulder of wheelchair weight and profile (folding versus rigid) and location of chair placement in the car (front or back seat) during chair lift (Research Aim 2).  Finally, we will assess the stresses on individual shoulder structures and identify specific factors that can minimize the stresses through use of computational models (Research Aim 3).  The second activity - with support from the Project 2 (Virtual Reality (VR) and Gaming for Home-Based Motor Assessment & Training) group - will develop a virtual reality (VR)-based game of a home exercise program (HEP) for preserving shoulder (rotator cuff) function (D3: VR-Home Exercise Program (HEP) for Shoulder). 

3) The population to be served: The rehabilitation problem that we will address in this project is barriers to mobility both in the home and community for the person with aging with and into disability. The research activity of Project 3 will directly serve individuals aging with a disability who use a manual wheelchair for mobility in the home or community including, but not limited to, those with stroke, Parkinson’s disease, osteoarthritis, rheumatoid arthritis, SCI, lower extremity amputation, poliomyelitis, cerebral palsy, myelomeningocele, Guillain Barre syndrome, and multiple sclerosis.  The development activity of Project 3 will directly benefit all individuals who use a manual wheelchair (to prevent development of shoulder pain), but also has the potential to benefit all individuals with shoulder pain related to rotator cuff impingement.  We will identify the impact of age and muscle strength on performance of the investigated mobility activities.  This information will guide our recommendations to preserve mobility in the home and community across the life-span.

4) The expected outcomes: The research activity of Project 3 will allow us to characterize and optimize home and community transfer function for manual wheelchair users aging with and into disability. Based on our focus-group discussions and information gathered from biomechanical and computer model investigations of the demands of the transfer activities, we will develop a consumer report-style matrix that provides clinicians and end users with accessible, objective information about what characteristics are important for safe and less stressful home and car transfers and wheelchair loading. The development activity of Project 3 will result in the creation of the necessary technology to make game controllers that produce strengthening and flexibility in the critical shoulder muscle groups of manual wheelchair users to enhance shoulder protection across the life span.