Computer Access for People with Disabilities: A Human Factors Approach, 1st Edition (Hardback) book cover

Computer Access for People with Disabilities

A Human Factors Approach, 1st Edition

By Richard C. Simpson

CRC Press

339 pages | 146 B/W Illus.

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Hardback: 9781466553712
pub: 2013-01-11
eBook (VitalSource) : 9780429097799
pub: 2013-01-11
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Incorporating Compass Computer Access Assessment software, Computer Access for People with Disabilities: A Human Factors Approach provides the information clinicians need to know in order to provide effective alternative computer access solutions to individuals with disabilities. Originally developed for a masters-level course on computer access for rehabilitation engineers and rehabilitation counselors, it provides practical guidance on how to provide computer access services and sufficient background knowledge to allow the reader to interpret the research literature.

  • Presents technology for individuals with physical, cognitive, and sensory impairments, and for older adults
  • Covers text entry devices, pointing devices, switch access, automatic speech recognition, and web accessibility
  • Emphasizes fundamental concepts and principles that remain true regardless of which specific operating system or product is being used
  • Draws on research from the fields of rehabilitation engineering, occupational therapy, and human-computer interaction (HCI)


"… makes an assumption that the reader has some experience in both applying human factors methodologies and working with populations with physical and/or cognitive disabilities. The writing is very straightforward and aims to guide practitioners to adapt their traditional methodologies to assessing the abilities of individuals with various types and degrees of impairment. The book especially excels in adapting pointing and text entry tasks to individuals with motor impairments (e.g., grasping or manipulating a mouse). Myriad design features such as key size, resolution, sensitivity, and labeling contrast are covered in depth. Even word prediction/completion software and automatic speech and voice recognition software are thoroughly detailed. The author also gives an excellent overview of signal detection theory, even going so far as to guide practitioners step by step on how to conduct these types of analyses in Microsoft Excel. … The book delves deeply into accommodations for individuals with musculoskeletal disorders and would definitely be recommended as a primer for any professional looking to engage in computer access evaluations with that populace. Furthermore, I found the author’s coverage of automatic speech recognition (ASR) to be particularly useful in my own research, as he does a thorough job of explaining the benefits and potential pitfalls of interfaces utilizing ASR. In addition, he delves into how one would go about assessing the efficacy of such interfaces when the intended user base may deal with a variety of physical and/or cognitive limitations. … This book is an excellent read, and I recommend it to any human factors professionals looking to adapt their methodologies to work with groups or individuals with varying levels of physical and/or cognitive impairments, with the caveat that more specific works may be better for working with individuals with certain severe sensory impairments (i.e., blindness or deafness)."

—Jared M. Batterman, MS, PhD Student, School of Psychology, Georgia Institute of Technology, Atlanta, USA, from Ergonomics in Design, October 2015

"What I like most about the book is its focus on the needs of the intended readership. The book offers some unique information that is not easy to acquire elsewhere potentially useful for readers outside the target users. Example, all aspects described in the section ‘word prediction/completion’ are of eminent interest for about two-thirds of the world population who use Short Message Service via mobile devices."

—Ahmet Çakir, from Behaviour & Information Technology, 2013

Table of Contents


How Many People Need Alternative Computer Access Technology?

Importance of Computer Access

The Digital Divide


User Modeling

Keyboard-Only Access


Input Focus


Mouse Keys

Appendix: Keyboard Access to Windows 7



Characterizing Switches

Switch Configuration Options

Switch Interfaces for Computer Use

Switch Positioning

Scanning Interfaces

Morse Code

Modeling Switch Input Methods

Appendix: Choosing the Scan Rate



Types of Pointing Devices

Modeling Performance on Pointing Tasks


In the Clinic

Appendix: Measuring Performance on Pointing Tasks

Appendix: Speed-Accuracy Operating Characteristic (SAOC)

Text Entry


Describing Keys

Describing Keyboards

Physical Text Entry Devices

Keyboard Modifications

On-Screen Keyboards

One-Digit Text Entry

One-Handed Text Entry

Two-Handed Text Entry

Assessment Issues

Appendix: Unconstrained Text Entry Tasks

Appendix: Signal Detection Theory

Techniques for Increasing Text Entry Efficiency


Word Prediction/Completion

Character Prediction

Abbreviation Expansion

Automatic Speech Recognition


How ASR Works

Benefits of ASR

Limits of ASR

Text Entry Rate with ASR

ASR Commands


ASR and Special Populations

Voice Ergonomics

Maximizing Performance with ASR

In the Clinic

Hearing Impairment

Hearing Loss

Computer Access Interventions for Hearing Loss

Visual Impairment


Visual Impairments

Keyboard-Only Access

Interventions for Poor Vision

Screen Magnifiers

Screen Reader

Braille Display

Cognitive Impairment

Learning Disabilities

Developmental Disabilities and Acquired Brain Injury

Computer Access for Older Adults

Increasing Number of Older Adults Online

Obstacles to Computer Use

Effects of Aging

Computer Access Challenges


Web Accessibility


Why Are Websites Inaccessible?

Measuring Website Accessibility




Musculoskeletal Disorders

Risk Factors

The Ergonomics Toolbox

Assessment Issues

Case Study



Assessment Process

Designing Solutions



Obstacles to Good Assessment

Appendix: Decision Making

Legislation Relevant to Computer Access

Americans with Disabilities Act

Telecommunications Act of 1996

The Rehabilitation Act of 1973 (as Amended in 1992 and 1998)

The Technology-Related Assistance Act for Individuals with Disabilities of 1988 (The Tech Act)

Twenty-First-Century Communications and Video Accessibility Act

Appendix: Voluntary Product Accessibility Templates

About the Author

Richard Simpson is an Associate Professor in the Department of Rehabilitation Science and Technology at the University of Pittsburgh, Pennsylvania.

About the Series

Rehabilitation Science in Practice Series

Learn more…

Subject Categories

BISAC Subject Codes/Headings:
COMPUTERS / Social Aspects / Human-Computer Interaction
MEDICAL / Physical Medicine & Rehabilitation
TECHNOLOGY & ENGINEERING / Industrial Health & Safety