Background

Ewen B. Lavoie1, BSc., Elizabeth A. Crockett1, BSc., Ognjen Kovic1, Aida M. Valevicius2, MSc., Quinn A. Boser2, BEng., Patrick M. Pilarski3, PhD., Albert H. Vette2, PhD., Jacqueline S. Hebert3, MD FRCPC, & Craig S. Chapman1, PhD.

1Faculty of Physical Education and Recreation, 2Department of Biomedical Engineering, 3Division of Physical Medicine and Rehabilitation, University of Alberta

ESTABLISHING NORMATIVE EYE MOVEMENT PATTERNS IN UPPER-LIMB FUNCTIONAL TASKS

Results

Conclusions

Advancements in Upper-limb Prostheses • Multiple degrees of freedom • Software integration • Multiple inputs for control

References [1] Hebert, J.S., et al. (2014) IEEE Trans. Neural Syst. Rehabil. Eng. 22(4): 765-773. [2] Biddiss, E.A., & Chau T.T. (2007) Prosth. Orth. Int. 31: 236-257.

4-280 Van Vliet Centre, University of Alberta, 116 St & 85 Ave, Edmonton AB, T6G 2R3

Contact: elavoie@ualberta.ca

1. When moving objects in sequence, able-bodied individuals exhibit prominent look-ahead fixations 2. Able-bodied individuals spend little, if any, time fixating on their own hand

3. Prosthetic users do not exhibit strong look-ahead fixations, and spend significant time fixating on their terminal device, especially during object transport

Reinnervation Surgeries

Complete data collection from prosthetic users, including some with increased sensory feedback from specialized prostheses Data collection from able-bodied participants using a specialized sensorimotor bypass prosthesis

Potential data collection from individuals experiencing other sensorimotor neurological deficits

Future Directions

Objectives Long-term • Use limb and eye tracking technologies to provide a more sensitive

measure of prosthetic limb use with and without sensory feedback [4]

Current project • Establish normative eye tracking data from able-bodied subjects

on 2 functional tasks • Simple enough to gather data from • Complex enough to emulate day-to-day movements

Supplementary project • Preliminary comparison of eye movements of prosthetic users to

those of able-bodied participants

Current Evaluation Procedures • Box and Blocks [3]

• Fails to give robust information • Clinical assessments

• Expensive, inconsistent, time intensive

Upper-limb Prostheses Rejection Rates • Passive 39% • Body-powered 26% • Myoelectric 23% [2]

Methods Equipment • Binocular 60 Hz mobile Eye-tracker

Cups Pasta 1. Eye tracking Only

2. Motion tracking Only 3. Both eye and motion tracking

SCENE CAMERA

PUPIL CAMERAS

• Synchronization of eye and motion tracking systems • Enables segmentation of eye data by phase of movement

• 120 Hz Motion tracker with 12 IR cameras

Participants • 20 able-bodied (complete) • 6 prosthetic users (in progress) Protocol • 20 repetitions of 2 daily living tasks under 3 conditions (120 trials)

Normative Eye Behavior

Pros

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20 A

ble

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Time (s)

Fixation Location vs Time during Cups Task

Cur

rent

Lo

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Other

Segments

Futu

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Loca

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Prosthetic User Eye Behavior

Normative vs Prosthetic User Eye Behavior

This work was sponsored by the Defense Advanced Research Projects Agency (DARPA) BTO under the auspices of Dr. Doug Weber through the [Space and Naval Warfare Systems Center, Pacific OR DARPA Contracts Management Office] Grant/Contract No. N66001-15-C-4015.

Look-ahead Fixations Grasp Release

Grasp and Transport Release

0.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00 80.00 90.00 100.00

Release

Transport

Grasp

Reach

Cups Task - Normalized Fixation Time (%)

Current Future Hand

[1]

[3] Mathiowetz V., et al. (1985) Amer. J. Occ. Ther. 39: 386-391. [4] Sobuh, M., et al. (2014) J. Neuroeng. Rehabil. 11: 1-11.