RESNA 27th International Annual Confence

Technology & Disability: Research, Design, Practice & Policy

June 18 to June 22, 2004
Orlando, Florida

Mobile Usability Lab (MU-Lab): A Tool For Studying Medical Device Accessibility

Jack M. Winters1, Molly Follette Story2 ,
Sean Campbell 1, Melissa Lemke1, Sarma Danturthi1, Alan Barr2 and David M. Rempel2
Rehabilitation Engineering Research Center on
Accessible Medical Instrumentation
1Department of Biomedical Engineering,
Marquette University, Milwaukee, WI 53233
2University of California at San Francisco,
Ergonomics Laboratory, Richmond, CA 94804


The Mobile Usability Lab (MU-Lab) is a tool being developed by the Rehabilitation Engineering Research Center on Accessible Medical Instrumentation (RERC-AMI) to study the usability of targeted medical devices by individuals with diverse abilities. The system integrates data collection hardware and software, and provides a Protocol Manager that helps facilitate problem identification, planning, data collection and data analysis across the continuum of the medical instrumentation analysis process. Two full systems are being implemented and evaluated, one based at Marquette University and one at the University of California Ergonomics Laboratory.


Usability, accessible design, medical instrumentation


This paper describes a state-of-the-art usability analysis tool that is designed to be mobile and to meet the needs of the Rehabilitation Engineering Research Center on Accessible Medical Instrumentation (RERC-AMI), MU-Lab. This technology will be used for a variety of RERC-AMI projects, including:

It is specifically designed for detailed multi-site product accessibility and usability analysis that can be made at a diversity of locations in the greater Milwaukee area (based at Marquette University) and San Francisco Bay Area (based at the University of California Ergonomics Lab). It is being co-designed by the authors, some from each campus.


The first aim for the team, which communicates through email and one-three videoconferencing meetings each month, was to refine the design specifications. This process took advantage of team expertise in universal design principles (1), ergonomics, usability analysis methods and accessible design. Specification requirements included:

These specifications have been met through an iterative process.


MU-Lab uses two carrying cases, a primary case with customized interior foam for housing cameras, tripods and all related equipment other than the laptop and its components, and a second for the laptop computer and its components. Up to four video channels can be integrated into data collection, with several types supported since some environments are expected to involve placement challenges, such as a wide-angle camera for tight settings or a camera with strong zoom capability that must be located at a distance.

The entire data analysis process is coordinated through the Protocol Manager, which was designed through a systematic iterative process that involved over 20 versions by the team. The final specifications are implemented in ASP.Net, C# and XML software in the Microsoft's Video Studio .Net environment, and is available through a login-protected web site. The Protocol Manager guides the user through all aspects of the overall task evaluation process for a given target category of medical instrumentation. This includes cases where the human subjects may involve a practitioner as well as the patient/client. The software can be implemented on a single computer to procure data, or directly to the project web site when an Internet connection is available. The software also has a save and lock mechanism to protect data from accidental overwriting.

Real-time data analysis makes use of Synchronized Video Data Acquisition (SVDA™) software that is developed, along with Multimedia Video Task Analysis (MVTA™) for subsequent task analysis, by Drs. Robert Radwin and Thomas Yen at the University of Wisconsin – Madison (distributed by NexGen Ergonomics). A data acquisition card (NI-DAQ, PCMCIA port) is available for sensor data collection. MVTA provides an iterative environment for ergonomic task analysis. Also available for data analysis are several video editing packages that make use of Adobe Premiere but add speed and a rich collection of features: Canopus DVStorm2 and Matrox RT.X100. The Protocol Manager is used to help integrate the multi-site data analysis process.

In summary, the MU-Lab provides a tool for sophisticated usability analysis that explicitly integrates in principles of universal design and considerations of accessibility. While focused on the needs and projects of the RERC-AMI, none of the specifications, components and capabilities are proprietary, and the team is open to collaborative relationships.


  1. Story MF, Mueller J. Universal Design Performance Measures for Products. A Tool for Assessing Universal Usability. In Emerging and Accessible Telecommunications, Information and Healthcare Technologies , Winters JM, Robinson CJ, Simpson RC and Vanderheiden GC, eds., Arlington: RESNA Press, 2002.


This work is supported by the Rehabilitation Engineering Research Center on Accessible Medical Instrumentation, funded by the National Institute on Disability and Rehabilitation Research, U.S. Department of Education Grant #H133E020729. All opinions are those of the authors.

Author Contact Information:

Jack Winters, Ph.D.
Professor and John P. Raynor Distinguished Chair, Department of Biomedical Engineering
Marquette University,
PO Box 1881,
Milwaukee, WI 53201,

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