Technical Report AMI-MU-005:

Weight Scales

Authors: Elizabeth Omiatek, B.B.E., Ashley French, Melissa Lemke M.S., Anne Yatco

Coordinating Editors: Jack Winters, Ph.D., Jill Winters, Ph.D., R.N.

Location: Medical Device Accessibility & Usability Laboratory

Current Version: 1.0 (March 2006)

Table of Contents

Executive Summary

People with disabilities need accessible medical instrumentation to accommodate their specific healthcare needs. An example is a weight scale. The main reason for having an accessible weight scale available is to improve the quality of care for people with disabilities and activity limitations. Features of a range of weight scales on the market, 35 total, are summarized in tabular form. Possible benefits of weights scales that include accessible features are addressed.

Background

Medical devices, in general, should be accessible to patients with disabilities in order to provide these patients with the same quality care that patients without disabilities receive. Patients who are not able to use a weight scale receive a lesser form of patient care. Without an accurate measurement of weight, a missed diagnosis or an incorrect dosage of medication may be given. Obesity is also linked to a number of health risks including:

Besides obesity, involuntary weight loss can also be a sign of a health risk. Weight loss may indicate depression, risk for infection, cancer, cardiac disorders and benign gastrointestinal diseases. Although not as common, these risks are also very serious and important in determining a diagnosis and a prognosis.

Weight scales with accessible features could benefit all populations including people who depend on assistive devices such as wheelchairs or walkers. Also, people with activity limitations or people who surpass a typical weight scale’s limits will benefit from an accessible weight scale. People with activity limitations include people who have difficulty with walking, climbing and using steps. In addition, accessible weight scales will assist people with joint pain, pregnancy, fatigue, respiratory and cardiac conditions, post surgical conditions and orthopedic injuries.

Also, there are a number of legal obligations for considering accessible weight scales, including Title III of the Americans with Disabilities Act and the advantage of the federal tax incentives for improving accessibility. Accessible weight scales may also reduce healthcare provider workplace injuries.

Recently Lemke (2005) performed a systematic usability and accessibility analysis of several weight scales on the market. This has helped refine the RERC-AMI’s knowledge of the types of features that make a weight scale less and more accessibly, and why. This new knowledge makes this technical report even more valuable, and is one part of the process that will eventually enable a full accessibility evaluation for all of these existing products in this category.

Product Table

For an overiew and instructions on how to navigate within the product table click here.

Product Survey

The Product Table compares many different models of weight scales, with various designs for accessibility. Key features were compared to evaluate the possible accessibility of each scale for users with various disabilities.

Four general categories were used in comparison; wheelchair accessible scales, handrail scales, platform scales, and specialty scales. The columns address different qualities of each weight scale, including the weight limit, portability, means of entering the scale, manual or powered read-out, dimensions of the scale and of the platform, presence of arm rails, power source, measurements taken by the scale, and display type.

The columns following these initial qualities rank the scale’s accessibility for users with different disabilities on a scale of 1 to 3.

Disabilities examined included hearing impairments, speech impairments, difficulties with hand, arm, and eye coordination, and impairments with balance or posture. For example, a platform scale would be given a rank of “1” for the disability of impaired balance. A scale with a seat would be given a rank of “3” for the disability of balance impairment.

The column labeled “Generally Accessible Device,” is a broad ranking of accessibility based on if the scale design looks largely accessible, if the keypad is accessible to the user, and how many of the subsequent categories the scale is found to be accessible.

Product Evaluation

This compilation of 35 available weight scales supports the idea that new developments in accessible weight scale design are needed. There were very few scales that accommodate both wheelchairs and patients with impaired balance, which limits the universal accessibility of that device. This also causes an increased cost for medical environments in which the scales are being used. This is a result because more than one kind of scale would need to be purchased in order to accommodate users of all abilities. Another option for future designs may be a design for a weight scale with additional modular devices. These devices could be added or subtracted from a basic accessible weight scale design.

Recommendations for R&D

Desirable features of an accessible weight scale include (see also Lemke 2005):

Acknowledgment

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.

References

  1. American Association of Retired Persons. Beyond 50 2003: A report to the Nation on Independent Living and Disability. Place: Publisher, 2003.
  2. Center for Disabilities Issues and the Health Professions, http://www.cdihp.org/
  3. Department of Health and Human Services, http://www.hhs.gov/asl/testify/t970430a.html
  4. Lemke, L., Biomedical Engineering M.S. Thesis, Marquette University, 2005.