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RERC-I Final Report-(1993-98)


D-4: Standardized Postural Measures in Support of Quantification of Seating Outcomes

Task Leader: Douglas Hobson, PhD (Rehabilitation engineer)

Co-investigators: Mark Schmeler, MS, OTR/L, ATP (seating clinician); Elaine Trefler, MEd, OTR/L, ATP (seating clinician); Rachid Aissaoui, PhD (bio/mechanical engineer); Graduate Student Researcher

Duration/Staging of task: This 27-month development task will occur in months 33-60 of the 60-month RERC cycle, commencing in September 2001.

This task proposes to address deficiencies in seating outcomes measures by taking a new and more holistic approach to the quantification of wheelchair seated posture. Standardized quantification of wheelchair-seated posture through development and validation of a practical measurement system will lay the foundation and structure for qualitative outcome measures related to wheelchair seating intervention.

This study has the real potential of providing a conceptual shift in the way seating intervention is measured and documented. If successful, this could have profound impact on the clinician's ability to better document and communicate seated wheelchair posture. Moreover, it can lead to the development of clinical tool(s) that can quantitatively document outcomes in terms of improvement to seated posture. The most optimistic outcome would be the adoption of the concepts and related process as the "gold standard" for documenting and communicating seated posture. This could also provide a quantitative tool for standardizing the communication between clinicians and third party payers.
If successful as planned, this task will also lay the foundation for development and marketing of commercial tools to automate the process. To this end, this development will be directly useful to manufacturers wishing to design products to universal standards that have the potential for widespread application. If adopted widely, it will facilitate the clarification of terminology related to the description of wheelchair seated posture, a potential benefit to all involved with wheelchair seating technology.

And finally, benefits will be realized by wheelchairs users and the seating supply industries as adoption of tools of this kind will progress the field of wheelchair seating from one that today is still largely a subjective art, to one founded on research and resulting quantitative measures. So doing will help move the seating field more into the mainstream of required rehabilitation services.

Development activities

To develop and evaluate a system, complete with clinical measures, for the quantification of wheelchair seated posture.

1. To develop the conceptual model, including relevant terminology that will serve as the foundation for the measurement, recording, and communication of seated posture.
2. To develop and evaluate the clinical measures that will be used to define and record a person's wheelchair seated posture.
3. To compare the above quantitative approach to the existing Seated Postural Control Measure (SPCM) and identify compatible components.
4. To develop and disseminate product specifications for the design of clinical tools that will facilitate the measure, recording, and documentation of a person's wheelchair seated posture.
5. To disseminate the outcomes to stimulate additional research and adoption by service providers and wheelchair seating industry.

Schematic of proposed reference system:

Schematic of proposed reference, system grpahic. Please contact task leader for additional information


Progress Report (12/31/00): This task does not begin until 2001.

Expected Outcome
Not all of the above potential benefits can possibly be realized by this first development effort. This task should be viewed as an explorative effort into a new dimension for wheelchair seating standardization and tools for outcomes documentation. To fully realize the above outcomes and benefits, additional research in terms of clinical validation will be required. This task will be highly successful if it results in the stimulation and guidance of future studies to address issues not feasible within the time and resources of this task.


Contact Person: Douglas Hobson


As of October, 2002, ISO 16840-1, (seating posture measurement standard) has progressed to the DIS voting level, which is expected to take place in early 2003. RERC staff have provided significant leadership (Barb Crane-Working Group Chair) and editorial support towards this outcome. The RERC has also conducted the first stage of clinical validation of the key principles within the standard. This was done by contracting the services of four leading seating clinicians who then followed an evaluation protocol, using a postural measurement frame(PMF), designed and produced by the RERC. Feedback from the evaluation was then used to help guide the revision the CD draft of the standard, as well as to upgrade the design of the PMF. In addition, instructional workshops were given by the task staff (Hobson, Crane), with assitance from consultants, at the ISS-2002 meeting in Vancouver, and the RESNA-01/02 conferences. Future presentaions are planned for ISS-2003 in Orlando Florida and RESNA-03 in Atlanta. The RERC staff are also collaborating with colleagues in England, Sweden and Japan who are conducting similar clinical evaluations.


Clinical evaluation: neutral posture, saggital thigh angle, frontal pelvic angle, sagittal neck angle

Postural Measurement Frame: side view, rear view






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