Independent Wheelchair Transfers in the Built Environment: How Transfer Setup Impacts Performance Phase 2: Final Report

Background

Wheelchair use in the United States is at an all-time high and continues to grow. In 2010 approximately 3.6 million non-institutionalized Americans aged 15 and older required a wheelchair to assist with mobility compared to 2.7 million Americans who were using wheelchairs in 2002 [1, 2]. For those who use a wheeled mobility device (WMD) transfers are required to perform essential tasks of daily living such as bathing, toileting and driving (see Addendum B for a complete listing of all the abbreviations used in this report). Transfers are also required for enabling participation in a wide variety of community settings such as restaurants, parks, pools and medical offices. On average transfers are performed between 11 and 20 times per day [3, 4]. Independent transfers are ranked among the most strenuous tasks of daily living because of the high mechanical demands they place on upper limbs [5]. The built environment can either increase or decrease the effort required to perform independent transfers [6].  Environments that require more effort to transfer ultimately limit the numbers of WMD users who can access them. 

Current accessibility standards include criteria related to seat height, clear floor space, and grab bar placement in places where transfers are expected [7]. There is a general concern that the standards are outdated as they were developed in the 1980's and mobility devices and the demographics of those using these devices have evolved over the last few decades. Wheelchair technology has also changed since these standards were made. Power wheelchairs are larger in size due to add-ons like powered recline and tilt and the users themselves have also grown with more bariatric chairs being developed. Over the last decade, accessibility standards have also expanded and the number of seating surfaces designed for transfer has increased to more elements designed for transferring to elements at recreational facilities like play areas, swimming pools, and amusement rides. 

In order to gather data that would support updates and expansions to the guidelines in these and other areas, a two phase study, including the one that is being reported on in this report, have been completed. The first phase evaluated the state of the science concerning independent wheelchair transfers and in particular how various aspects of the built environment affect the transfer process.  This phase also included an experimental study to examine the design standards for amusement park rides and transfers to other similar kinds of elements [8]. One-hundred and twenty adult WMD users were tested and the primary outcome measures collected were the maximum and minimum attainable vertical heights of the transfer surface, maximum gap distance between the WMD and transfer surface, grab bar use, and WMD space needs (see http://herl.pitt.edu/ab/ Phase I Final Report for detailed results on this study).

While the first phase addressed some of the key environmental issues concerning transfers, there were some additional issues that the Access Board felt needed further research.  For instance, phase 1 was unable to address all possible elements that might be encountered in the environment.  Transfers steps, which require performing multiple transfers from one platform to another  platform, are one option that is provided for adults and children when transferring into or out of an amusement ride car, a swimming pool or a piece of playground equipment to help them overcome the large vertical distances separating the WMD height and the target seat height. Research is needed to know if the current requirements for transfer steps (e.g. step widths, step heights, grab bar setup and clear floor space in front of the first step) meet the needs of current WMD users.  Another place where more evidence is needed concerns the proposed standard for transfers to medical diagnostic equipment. For example, the appropriate transfer surface dimensions, vertical heights from the floor, floor space around the exam surfaces, backrests and handheld dimensions are all issues that are under discussion and that require further research.

With the procurement of additional funding, a second phase of research was conducted. This phase included conducting a web-based live workshop to act as a forum for exchanging ideas and information related to the first phase of research and to identify research priorities related to independent transfers in the built environment (see http://herl.pitt.edu/ab/ IWT Workshop Proceedings for detailed results on this study).  Using the feedback collected during the workshop combined with the need for additional information on platform transfers and transfer steps, a follow up study was performed. This report describes the details and results of this study.

Study Objectives

The purpose of this study was to examine independent transfers to and from a WMD and a simple platform, with and without the use of grab bars and/or a backrest, and transfers between two platforms (e.g. two-step transfer).  The specific objectives were to:

1. Define population-based percentiles for:

a. Level, highest and lowest heights for transfers to i) a seat with no handhelds present, ii) a seat with grab-bars and iii) a seat with grab-bars and a backrest.

b. Seat widths needed for each level, highest and lowest transfers to i) a seat with no handhelds present, ii) a seat with grab-bars and iii) a seat with grab-bars and a backrest

c. Floor space needed for level, highest and lowest height transfers to seats without handhelds, with grab-bars, and with grab bars and a backrest

d. Highest and lowest heights for a two-step transfer with and without an integrated ramp

2. Determine user preferences for grab bar and backrest heights and prevalence of grab bar and backrest use in each type of transfer.

3. Determine the relationship between grab bar and backrest presence and transfer ability.  We hypothesized that grab bars would enable participants to perform higher or lower transfers.