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Susan I. Fuhrman, BSME, Mary Ellen Buning, PhD, Patricia Karg, MSBME

Rehabilitation Engineering Research Center (RERC) on Wheelchair Transportation Safety
Department of Rehabilitation Science and Technology,
University of Pittsburgh / Pittsburgh, Pennsylvania 15260

Abstract

A questionnaire was developed to better understand which postural support devices are most frequently prescribed for wheelchair users and to determine which postural support devices create the greatest concern for user safety during transit in motor vehicles. The questionnaire was posted on listserves used by seating and mobility clinicians; seventeen clinicians responded. Results indicate that prescription patterns are similar for both pediatric and adult clients. Pelvic positioning belts are prescribed most frequently followed by headrests, lateral supports and chest harnesses. The postural support device of most concern was the head restraint, followed by chest harnesses, subASIS bars and headrests. Several clinicians indicated that specific secondary postural supports were required for transit in their districts.

Keywords

postural support device; safety; wheelchair; transportation

Background

According to the Department of Transportation, over 500,000 individuals with disabilities who never leave their homes report difficulties with transportation [1] . Accessible transportation has been identified by the National Organization on Disability as key to workplace and community integration; likewise, poor access to transportation acts as an integration barrier [2] . Once an individual who uses a wheelchair boards a vehicle, there can still be significant difficulties in safely transporting the wheelchair-seated occupant.

In general, wheelchairs are designed to enhance users’ mobility, while automotive seats are designed to provide safety and comfort for occupants while anchored to the vehicle frame [3] . Furthermore, wheelchair postural support devices that will enhance mobility may pose an injury risk during transportation. Primary postural support devices are defined as the seat and the seatback; secondary postural support devices (SPSD) are all other postural supports including: headrests, chest harnesses, neck supports, head straps, pelvic positioning belts, lateral supports, etc.

Current standards primarily address the issues of SPSDs in three ways [4-8] . One is through recommendations that wheelchair and WTORS manufacturers are required to include in their user instructions and warnings, and through required product labeling. The second is through a design requirement that all sharp edges be covered with energy-absorbing material to minimize the potential for puncture injuries and lacerations in a crash. Finally, wheelchair standards require that no rigid components with a mass greater than 100 g become detached from the wheelchair during the frontal impact test.

In contrast, automotive manufacturers take a different approach and look at seat components such as headrests as safety devices to prevent whiplash associated disorders [9] . While wheelchair users’ seating needs may vary, it is necessary to evaluate which SPSDs are commonly used and which ones create safety concerns. Evaluation of the performance of the most frequently used SPSDs will provide information that can be used to enhance the safety of the wheelchair-seated rider.

PURPOSE

The purpose of this research was to determine: usage rates for specific SPSDs, adult usage as compared to pediatric usage, differences in prescribing practices of clinicians that have pediatric versus adult clients, SPSDs that are of most concern to clinicians, and specific requirements of school districts for use of SPSDs.

METHODOLOGY

A questionnaire was developed to gather information on SPSD practice. Data of interest were clinician descriptions of clients including percent of adult and pediatric clients and the distribution of diagnoses in their caseloads. The questionnaire queried clinicians on the approximate percentage of their clients that use specific secondary postural support devices. For each device, clinicians used a Likert scale to indicate the degree of their concern for injury from the device in a crash, and to describe the nature of their concerns. Last, the questionnaire asked clinicians to identify which SPSD are required for students or adults who are transported in their district or program.

The questionnaire was evaluated for understandability and clarity by two clinicians in the Center for Assistive Technology (University of Pittsburgh Medical Center Health System) and then posted on the following listserves: SIG 09 (RESNA), RESNA listserve, and Tech SIS (AOTA). Responses were entered into an Excel spreadsheet and ranked.

RESULTS

Seventeen clinicians responded including seven occupational therapists, five physical therapists, and three rehabilitation engineers. Most of the respondents (15) have a mixed clinical practice with both pediatric and adults clients. Results are presented for three categories : all clinicians , those that have >80% adult clients, and those that have >20% pediatric caseload. A 20% pediatric caseload corresponds to approximately one day per week. The clinicians reported having been in practice on average for 14.9 + 9.2 years, with a range of 3 – 30 years, and a median of 15 years experience. One clinician sees only adult clients and did not respond to those questions pertaining to pediatric clients; likewise another clinician sees only pediatric clients and did not respond to those questions pertaining to adults.

The data for adult clients indicated that clinicians that see fewer pediatric clients prescribe secondary postural supports less frequently than those that see more pediatric clients. Yet, when the adult-client data was ranked, there were only small differences between respondents that saw more pediatric clients and those that saw fewer. All respondents ranked pelvic positioning belts, headrests, lateral supports and chest harnesses in the top four most frequently prescribed SPSDs. All categories ranked head restraints (head straps and neck supports) and subASIS bars as least frequently prescribed.

The prescription patterns for pediatric clients were similar to those for adult clients, for all three categories. Those clinicians that see at least 20% pediatric caseload prescribe SPSDs for their pediatric clients more frequently than those clinicians that see fewer pediatric clients. Yet, the four most frequently prescribed SPSDs are the same for all categories and the same as for adult clients. Of note, the ranks are the same, but the frequency of prescription for pediatric clients is higher than for adult clients, sometimes 1.5 times as high.

All practitioners reported concern for use of head restraints during a crash. Most also ranked chest harnesses and subASIS bars high for concern in a crash. This concern was related to improper usage and to entrapment when emergency evacuation is needed. Of least concern were lateral supports and thigh adductors. These responses were similar for both pediatric and adult clients as well as for clinicians that treat adults and for those that treat more children.

Six clinicians (35%) reported their program or district require specific SPSDs for transport. The most frequent requirements are for pelvic positioning belts, headrests and chest supports. According to the respondents, many school districts will not transport a child in a wheelchair unless the child has all of these devices – regardless of the child’s functional needs.

DISCUSSION

This survey was designed to aid this research team in determining which SPSDs warrant further investigation. The two issues are frequency of prescription and concern for crash safety. While pelvic positioning belts are usually prescribed, clinicians are not concerned about their safety – except when they may be confused with occupant restraints that meet federal safety standards. Conversely, while head straps and subASIS bars are infrequently prescribed, there is a great deal of concern about their safety during transit.

The greatest concern expressed in the survey echoed a survey done in two states over ten years ago [10] . At that time, respondents were asked in their survey to make recommendations for improvement of the methods of safe transportation; their most often cited recommendation was to provide head/neck support. It is extremely important for children riding on school buses to have their faces in a visible position. Children that use wheelchairs for mobility may also have respiratory or seizure problems and it is imperative that their faces be visible for signs of distress.

This was a small study (n=17) and survey respondents were self-selected. As such, they may be more aware of wheelchair transportation safety devices and practices than the typical seating specialist; this subset of clinicians may differ in prescribing patterns than the general population. Future work could focus on several areas. A larger study could be conducted to sample a greater number of clinicians. Specific questions could be added to clarify which SPSDs are commonly used together and in what combinations. In addition, clinicians could be asked which geographic area or school district they represent so that geographic representation could be assured.

ADDRESS

University of Pittsburgh / Department of Rehabilitation Science and Technology
Forbes Tower – Suite 5044
Atwood & Sennott Streets
Pittsburgh, PA 15260
412.383.6571

ACKNOWLEDGEMENTS

This research has been supported by the Rehabilitation Engineering Research Center (RERC) on Wheelchair Transportation Safety, NIDRR Grant #H133E010302.

REFERENCES

1. U.S. Department of Transportation Bureau of Transportation Statistics, Freedom to Travel. BTS03-08. Washington, DC.
2. National Organization on Disability, Access to Transportation. in http://www.nod.org/content.cfm?id=798. Last update: August 25, 2001. Accessed on: December 28, 2004.
3. Snell, M., Guidelines for safely transporting wheelchair users. OT Practice, 1999. 4(5): p. 35-8.
4. ISO, ISO 10542-2: Wheelchair tiedowns and occupant restraint systems/Part 2 - four point strap type tiedown systems.
5. ISO, ISO 10542-1: Wheelchair tiedowns and occupant restraint systems/Part 1 - Requirements and test methods.
6. Society of Automotive Engineers, SAE J2249: Wheelchair Tiedowns and Occupant Restraint Systems - Surface Vehicle Recommended Practice. Warrendale, PA. Jan, 1999.
7. ANSI/RESNA, ANSI/RESNA WC-19: Wheelchairs Used as Seats in Motor Vehicles. WC-19. Dec 1999.
8. ISO, ISO 7176/19: Wheelchairs Used as Seats in Motor Vehicles.
9. Welcher, J.B. and Szabo, T.J., Relationships between seat properties and human subject kinematics in rear impact tests. Accident Analysis & Prevention, 2001. 33(3): p. 289-304.
10. Everly, J.S., Bull, M.J., Stroup, K.B., Goldsmith, J.J., Doll, J.P., and Russell, R., A survey of transportation services for children with disabilities. American Journal of Occupational Therapy, 1993. 47(9): p. 804-10.