Evidence-Based Principles for Selecting Eye Gaze AAC Technology

Katya Hill, P.h.D., CCC-SLPSchool of Health and Rehabilitation Sciences

Department of Communication Science and Disorders

Department of Rehabilitation Sciences and Technology

AAC Institute

Overview on session: Evidence-Based Principles for Selecting Eye Gaze AAC Technology

• Focus on principles and evidence

• Identify candidates for eye gaze

• Identify features of eye gaze systems

• Discuss collecting clinical & personal evidence

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Focus on principles and evidence to guide clinical decisions for selecting eye gaze technology

Evidence-Based Principles for Selecting Eye Gaze AAC Technology

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Remote Eye Gaze Technology

• Vision-controlled direct selection technique

• More than bright and dark pupil tracking

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The important details• pupil-center/corneal-reflection method

• LED reflects a small bit of light off the surface of the eye’s cornea

• The light reflects off of the retina and causes the pupil to appear white

• Pupil effects are methods used to determine the gazepoint

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Viewing the Eye

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Glint-Pupil Vector

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How our eyes work

• Eye movement while reading

• Saccades and fixations

• Visual perception and language processing

• Errors: losing place, skipping words or not adequately processing visual information

• Poor readers: language skills vs. eye movement control

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http://www.visionforlearning.co.nz9

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IDENTIFYING CANDIDATES APPROPRIATE FOR EYE GAZE AS A SELECTION TECHNIQUE.

Evidence-Based Principles for Selecting Eye Gaze AAC Technology

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Overview of clinical populations

• Amyotrophic Lateral Sclerosis (ALS)

• Traumatic Brain Injury (TBI)

• Cerebral Palsy

• Multiple Sclerosis (MS)

• Muscular Dystrophy (MD), spinal muscular atrophy, Werdnig-Hoffman Syndrome

• Spinal cord injuries

• Strokes

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User considerations: Vision

• Good control of at least one eye.

• Common eye movement problems

– Nystagmus

– Alternating strabismus

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User considerations: Vision

• Adequate vision

• Corrected with glasses

• Inadequate visual acuity

• Soft contact lenses

• Diplopia

• Blurred vision

• Cataracts

• Homonymous hemianopsia

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User consideration: Vision

• Absence of side effects from medication

• Baclofen

• Anticonvulsants

• Antidepressants

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Top image: ptosis(drooping) eyelid

Bottom image: early cataracts visible over both pupils

Physiology Affecting Eye Tracking

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User considerations: Physical

• Positioning

– Ability to maintain a position in front of the eye gaze screen/camera

• Continuous, uncontrolled head movement

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User considerations

• Cognition

• Memory

• Language

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THE DESIGN AND FEATURES OF EYE GAZE SYSTEMS

Evidence-Based Principles for Selecting Eye Gaze AAC Technology

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Hill & Scherer, 2008; Hill, 2010 in press

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Tertiary components

Secondary components

User Interface Selection method Outputs

Primary components

Language representation methods

VocabularyMethod of Utterance

Generation

Examination of eye gaze technology as a selection technique

• Infrared exposure

• Calibration & defaults

• Gaze point predictions

• Dark versus light pupils

• 1 versus 2 cameras

• Narrow versus wide angle camera lens

• Sitting or reclining23

Camera Moveability & Position

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Flexible cameras allow unique client positions

Another unique position

On-screen eye image display

• Eye images are displayed for the user

• Decreases frustration: user knows what the camera sees. This is not a feature on many systems.

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Environmental issues affecting eye tracking

• Figure on left: light from window reflecting on eyeglass lens

• Figure on right: reflection eliminated by changing angle of earpieces

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User interface considerations

• Color and detail

• Alphabet displays

• Graphic symbol displays

• Navigation

• automaticity

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Examples of user interfaces

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Examples of user interfaces

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Examples of user interfaces

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Comparing Eye Tracking Systems

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PROCEDURAL PROTOCOLS FOR EVALUATING EYE GAZE SYSTEMS – PERFORMANCE AND OUTCOMES DATA

Evidence-Based Principles for Selecting Eye Gaze AAC Technology

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Computer-based evaluations and LAM datalogging

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COMPASS – Computer Access Assessment Software

• Assessment tool for computer access & AAC

• Eight skill tests

• Skills assessed include:

– keyboard and mouse use– navigation through menus – switch use.

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Copy Spell & Core Word Sentences

• Examples:

– I want to think about that.

– Why do you think that?

– He helped her with that.

– I can do this myself.

– Do you feel cold?

– She likes to be happy

– Give it to me. 37

Self-Created Utterances/Language Sample Context

• Examples:

– Picture Description

– Story Retell

– Narratives

– Conversation

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Performance Measures

• Communication Rates

– Ave. communication rate (wpm)

– Peak communication rate (wpm)

• Rate by language representation method

• Selection rate (bps)

• Rate index (wpb)

• Accuracy39

Video clip

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Know your numbers

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Know your numbersAnalysis of LAM data from ECO; Unity 144; Subject: K. Hill 26 January 2009 Task: Copy Core Sentences

Keyboard: right index

ECOPoint

Acceptance time (sec) - 0.7

Comm. Rate (average) 32.6 13.8

Comm. Rate (peak) 60.0 30.0

Fastest Utterance Where would you like to go

I want to go there

Comm. Rate (SEM) 36.5 11.3

Comm. Rate (SPE) 20.9 6.7

Selection Rate (bits/s) 10.8 13

Errors (%) 0 542

User Satisfaction - Outcomes

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Quest & PIADs

QUEST

• Self-administered 12-item questionaire

• Evaluates user satisfaction

• Yields three scores:

– Device,

– Services,

– total QUEST

PIADs

• 26-item, self-rating questionnaire

• Describes user experiences along three dimensions:

– Competence: Measures feelings of competence and usefulness.

– Adaptability: Signifies a willingness to try new things.

– Self-esteem: Indicates feelings of emotional wellbeing and happiness

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Surveying client preferences and satisfactions – outcomes data

SD D N S SA

I use multiple methods to communicate with family and care givers

My most effective method of communication is my eye gaze system

I have no problems with calibration of my system

I use my eye gaze system to write and save messages/letters

I am very satisfied with my accuracy using my system

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Rating Scale:

SA = strongly agree; A=agree; N=no opinion, D=disagree; SD-strongly disagree

Authors using eye gaze systems

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External evidence sources

• Text entry by gaze: Utilizing eye tracking. In I. S. Mackenzie & K. Tanaka-Ishii (Eds.)

• COGAIN: Communication by Gaze Interaction at http://www.cogain.org/

• Additional References

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Conclusions and Wrap-Up

• Safety and protection of clients

• Identify evidence-based marketing

• Need for data-driven decisions

• Suggest an ASHA technical paper

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Questions and Discussion

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Thank you!Katya Hill, Ph.D., CCC-SLP

Associate Professor

AAC Performance and Testing Lab

6017 Forbes Tower

University of Pittsburgh

Pittsburgh, PA 15260 US

412-383-6659

khill@pitt.edu

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www.aacinstitute.org

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References, cont.

Hansen, J. P., Torning, K., Johansen, A. S., Itoh, K., & Aoki, H. (2004). Gaze typing compared with input by head and hand.Paper presented at the ACM Symposium on Eye Tracking Research and Applications, San Antonio, TX.

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Hill, K., & Romich, B. (2001). A language activity monitor for supporting AAC evidence-based clinical practice. Assistive Technology, 13, 12-22.

Hill, K., Romich, B., & Spaeth, D. (2000). AAC selection rate measurement: Tools and methods for clinical use. In Proceedings of the RESNA '00 Annual Conference. Orlando, FL. July. pp 61-63

Itoh, K., Aoki, H., & Hansen, J. P. (2006). A comparative study of two Japanese gaze typing systems. Paper presented at the ACM Symposium on Eye Tracking Research and Applications, ETRA 2006, San Diego, CA.

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MacKenzie, I. S., & Soukoreff, R. W. (2002). Text entry for mobile computing: Models and methods, theory and practice. Human-Computer Interaction, 17, 147-198.

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References, cont.

Majaranta, P. & Räihä, K. (2007). Text entry by gaze: Utilizing eye tracking. In I. S. Mackenzie & K. Tanaka-Ishii (Eds.), Text entry systems: Mobility, accessibility, universality (pp. 175-187). New York: Morgan Kaufmann Publishers.

Pannasch, S., Helmert, J. R., Malischke, S., Storch, A., & Velichkovsky, B. M. (2008). Eye typing in application: A comparison of two systems in ALS patients. J. Eye Movement Research, 2(4), 1-8.

Stein JF. (2000). Monocular occlusion can improve binocular control and reading in dyslexics. Brain, 123, 164-170.

Wobbrock, J. O., Rubinstein, J., Sawyer, M. W., & Duchowski, A. T. (2008). Longitudinal evaluation of discrete consecutive gaze gestures for text entry. Paper presented at the ACM Symposium on Eye Tracking Research and Applications, ETRA 2008, Savannah, GA.

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