|
Items in cart [0] |
Questions? Call 888-624-8373 |
| ||||||||||||
| [ Top of Page ] [ Home ] [ Contact Us ] [ Help ] [ The National Academies Home ] | ||
Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter.
Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page R1
ELECTRONIC TRAVEL AIDS: NEW DIRECTIONS FOR RESEARCH
Working Group on Mobility Aids
for the Visually Impaired and Blind
Committee on Vision
National Research Council
National Academy Press
Washington, Die. 1986
OCR for page R2
NOTICE: The project that is the subject of this report was approved by
the Governing Board of the National Research Council, whose members are
drawn from the councils of the National Academy of Sciences, the
National Academy of Engineering, and the Institute of Medicine. The
members of the committee responsible for the report were chosen for
their special competences and with regard for appropriate balance.
This report has been reviewed by a group other than the authors
according to procedures approved by a Report Review Committee
consisting of members of the National Academy of Sciences, the National
Academy of Engineering, and the Institute of Medicine.
The National Research Council was established by the National Academy
of Sciences in 1916 to associate the broad community of science and
technology with the Academy's purposes of furthering knowledge and of
advising the federal government. The Council operates in accordance
with general policies determined by the Academy under the authority of
its congressional charter of 1863, which establishes the Academy as a
private, nonprofit, self-governing membership corporation. The Council
has become the principal operating agency of both the National Academy
of Sciences and the National Academy of Engineering in the conduct of
their services to the government, the public, and the scientific and
engineering communities. It is administered jointly by both Academies
and the Institute of Medicine. The National Academy of Engineering and
the Institute of Medicine were established in 1964 and 1970,
respectively, under the charter of the National Academy of Sciences.
Available from:
Committee on Vision
National Research Council
2101 Const itution Avenue
Washington, D.C. 20418
Printed in the United States of America
OCR for page R3
WORKING GROUP ON MOBILITY AIDS FOR THE
VISUALLY IMPAIRED AND BLIND
EMERSON FOULKE (Chair), Perceptual Alternatives Laboratory, University
of Louisville (low vision)
PAUL BACH-Y-RITA, Clinical sciences Center, University of Wisconsin
(physiology)
BRUCE B. BLASCH, Waisman Center, University of Wisconsin (blind
rehabilitation)
JOHN BRABYN, Smith-Kettlewell Eye Research Foundation, San Francisco
(rehabilitation engineering research)
JAY ENOCH, School of Optometry, University of California, Berkeley
(optometry, low vision)
ELEANOR E. FAYE, New York Lighthouse for the Blind (ophthalmology, low
vision)
GREGORY GOODRICH, Veterans Administration Medical Center, Palo Alto,
California (low vision)
ARTHUR H. KEENEY, Department of Ophthalmology, University of Louisville
(ophthalmology, ocular injuries)
LAWRENCE SCADDEN, Electronics Industry Foundation, Washington, D. C.
(low vision)
DAVID H. WARREN, Department of Psychology, University of California,
Riverside (psychology)
· · ~
OCR for page R4
COMMITTEE ON VISION
ANTHONY J. ADAMS (Chair), School of Optometry, University of
California, Berkeley
ROBERT SEKULER (Past Chair), Departments of Psychology, Ophthalmology,
and Neurobiology/Physiology, Northwestern University
IRVING BIEDERMAN, Department of Psychology, State University of New
York, Buffalo
RANDOLPH BLAKE, Cresap Neuroscience Laboratory, Northwestern University
RONALD E. CARR, New York University Medical Center
SHELDON EBENHOLTZ, Department of Psychology, University of Wisconsin
ANN B. FULTON, Department of Ophthalmology, Children's Hospital, Boston
CHRIS A. JOHNSON, Department of Ophthalmology, University of
California, Davis
JO ANN KINNEY, Surry, Maine
AZRIEL ROSENFELD, Center for Automation Research, University of
Maryland
PAMELA EBERT FLATTAU, Study Director
1V
OCR for page R5
FOREWORD
The Committee on Vision is a standing committee of the National
Research Council's Commission on Behavioral and Social Sciences and
Education. The committee provides analysis and advice on scientific
issues and applied problems involving vision. It also attempts to
stimulate the further development of visual science and to provide a
forum in which basic and applied scientists, engineers, and clinicians
can interact. Working groups of the committee study questions that may
involve engineering and equipment, physiological and physical optics,
neurophysiology, psychophysics, perception, environmental effects on
vision, and treatment of visual disorders.
To perform its role effectively, the committee draws on experts
from a wide range of scientific, engineering, and clinical disciplines.
The members of the working group responsible for this report were
chosen for their expertise in vision research and for their familiarity
-
w~th past efforts by government and private agencies to harness advanced
technology to serve blind and visually impaired persons. The report
reflects their evaluation of the usefulness and durability of uresent-
day mobility aids given the tasks confronting bland or visually impaired
pedestrians. The report provides an account of the mobility task and
of the r)ercentual . mini ~ ive, And maker f''n - it; rung:: ''navel vi no The
_ . . . . . .
_ ,
~ ~ _ _ _ _ = ~ , _ _ ~ _ _
performance of that task. The report describes the people who might
profit from using effective mobility aids and some of the techniques
currently being used to judge the effectiveness of available aids. The
report reviews information regarding the sensory systems available to
blind and visually impaired pedestrians and the possibilities for the
. ~ . . _ . . . . . . . . . . . .
application or new technologies to the mobility task given those
sensory processes.
The observations and recommendations arising from the efforts of
the working group merit consideration by mobility specialists whether
they are involved in the assessment and training of the blind and
visually impaired, the design of the mobility aids to serve the needs
of that population, or the support and conduct of basic research in
this area.
-
v
Anthony J. Adams, Chair
Committee on Vision
OCR for page R6
OCR for page R7
CONTENTS
PREFACE
SUMMARY AND HIGHLIGHTS
1: INTRODUCTION
The Problem of Mobility for Blind and Visually Impaired
Pedestrians, 5
The Mobility Task, 5
Abilities and Skills, 6
Establishing Performance Criteria, 7
Component Skill Criteria, 8
Guide to the Report, 8
2: THE DEMOGRAPHY OF BLIND AND VISUALLY IMPAIRED PEDESTRIANS
Some Definitions, 10
Demographic Characteristics, 11
Age, 13
Onset of Visual Problems, 15
Degree of Visual Impairment, 17
Additional Impairments, 18
Social Factors, 19
Approaches to Aiding Mobility, 20
Patterns of Use and Nonuse, 21
Recommendations, 23
Surveys of ETA Users and Technology Diffusion, 23
A Normative Data Base, 24
A Survey of the Needs of Older Blind People, 24
Review and Analysis of Existing Data Bases, 24
Study of Multiple Impairments, 25
Development of a Research Agenda, 25
3: THE ASSESSMENT OF MOBILITY
Individual Characteristics, 26
Psychosocial Characteristics, 27
Sensory and Motor Characteristics, 27
Perceptual and Cognitive Characteristics, 28
vii
xi
1
4
10
26
OCR for page R8
Measures of Mobility Performance, 28
Indirect Measures, 28
Direct Measures, 29
Outcome Measures of Successful Mobility, 30
Assessment of Mobility, 31
Assessment of Mobility Aids, 31
A Standardized Method for Assessing Travel Performance, 31
Recommendations, 33
Standardized Measures of Mobility Performance, 33
Simulation Methods, 33
Improved Field Assessment Techniques, 34
Technology Benchmarks, 34
Training Programs, 35
4: PERCEPTUAL , COGNITIVE , AND ENVIRONMENTAL FACTORS
The Mobility Task, 36
Perceptual, Cognitive, and Motor Functions, 36
Perceptual Information, 37
Cognitive Information, 39
Perceptual-Motor Skills, 42
Mobility Skills, 43
Applications of General Knowledge, 43
Applications of Specific Knowledge, 44
Individual Differences, 45
Risk Estimation and Risk Taking, 46
Early Versus Late Blindness, 46
Overprotection, 47
Neurological Damage, 47
Remaining Vision, 48
Conclusion, 48
Recommendations, 48
Making Information Available to the Blind Traveler, 49
Forms of Information Display, 50
The Relationship Between Perceptual and Cognitive
Information, 51
Perceptual Learning Principles, 51
SENSORY ENHANCEMENT AND SUBSTITUTION
The Visual System, 54
The Immediate Environment, 54
Remote Environments, 54
Sensory Enhancement, 56
The Auditory System, 56
The Somatosensory System, 5 7
Pressure, 58
Vibration, 58
Tactile Form Perception, 58
Texture, 59
Stereognosis, 59
Implications for Sensory Aids, 59
36
53
OCR for page R9
Existing Environmental Sensors, 60
Sonar Substitution, 60
Tactile Substitution, 61
Recommendations, 62
The Somatosensory System, 62
The Auditory System, 63
Mobility and Low Vision, 64
Detrimental Effects of Mobility Aids, 65
Animal Models, 65
6 THE TECHNOLOGY OF ELECTRONIC TRAVEL AIDS
Information Needs of the Pedestrian, 67
Past and Present Mobility Aids, 68
The Long Cane, 68
Electronic Travel Aids, 68
Clear-Path Indicators Versus Environmental Sensors, 69
Recent Developments, 70
Limitations of Existing Technology, 7 3
Recommendations, 74
Problem Definition, 75
Technology for Display Design and Simulation, 75
Technology for Optical Aids, 76
Technology for Information Acquisition, 7 6
Technologies for Information Display, 78
Technology for Information Processing, 80
REFERENCES
GLOSSARY
WORKSHOP PARTICIPANTS
SELECTED BIBLIOGRAPHY
1X
67
81
91
93
95
OCR for page R10
OCR for page R11
PREFACE r
At the request of the National Institute of Handicapped Research
and the National Science Foundation, the Committee on Vision established
the Working Group on Mobility Aids for the Visually Impaired and Blind.
The working group was asked to summarize current understanding of the
basic dimensions of mobility, to comment on the status of devices that
have been designed and built to assist the visually impaired people and
to determine a research agenda that would strengthen the knowledge base
underlying the design and use of mobility aids.
To accomplish these goals, the working group organized a workshop
to review what is known about the design and use of mobility aids by
visually impaired and blind people. Twenty-eight specialists in the
fields of demography, performance assessment and training, psychology,
geography, sociology, ergonomics, engineering, and physiology met for
two days in Washington, D.C., in November 1985. Workshop participants
were asked to consider the current state of mobility research and to
suggest what further research would improve the design and use of
mobility aids. Panels were formed and asked to address five major
questions:
Panel 1: Who are the people who might benefit from travel aids?
What dimensions might be used to classify them--along an age continuum,
by kind of visual impairment, by degree of impairment? How well have
people been able to use travel aids in the past? Why do some dis-
continue their use? In what ways are travel aids used differently in
different environments?
Panel 2: Which travel aids have worked, which have not? Which
which have not? How can training and
performance of visually impaired and blind people be assessed--by
stride length, for example, or by focusing on whole-body movement?
(The emphasis of this panel is the assessment of performance, not of
electronic or other aids.)
Panel 3: What do blind or visually impaired people need (or might
find useful) to know about the environment? Where in space is the
information to be found--e.g., in the path ahead, at the surface on
which they will walk? Are the processes involved conceptual? What is
their relative dependence on perceptual information or on information
retrieved from memory?
training methods have worked,
xi
OCR for page R12
Panel 4: What are the capacities of the different senses to
acquire information about space? How may acoustical and proprioceptive
stimuli be used? How should information about space be displayed?
Panel 5: What kinds of aids are needed, given what we know about
the kind of spatial information a person is likely to use? What are
the limitations of existing devices? What are the new directions that
might be taken in the development of new devices.
__;__ m=:
A background paper addressing the target questions was prepared for
each panel and distributed well in advance of the meeting. Participants
prepared a brief, informal response to their panel's background paper.
Background papers and panelist responses were disseminated to all work-
shop participants in advance of the meeting to facilitate workshop
-~rv~=ui~. finis report builds on those papers and comments as well
as on discussions that took place at the workshop.
In addition to the 28 participants in the workshop, a number of
people contributed in important ways to the success of the workshop and
to this report of its recommendations. Wayne Shebilske, the committee's
study director through June 1985, planned the workshop, and Pamela Ebert
Flattau, the committee's study director after July 1985, provided
important assistance in organizing the effort and in preparing the
workshop report. Gora P. Lerma, the committee's administrative
secretary, provided valuable secretarial and administrative
assistance. Christine L. McShane, editor of the Commission on
Behavioral and Social Sciences and Education, helped improve the style
and clarity of the report. And finally, Estelle H. Miller of the
National Academy Press lent her excellent production skills to the
project in preparing the report for publication.
Emerson Foulke, Chair
Working Group on Mobility Aids for
the Visually Impaired and Blind
xii
