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THE USE OF IN-EAR ACCELEROMETERS TO SIGNAL CONCUSSION THE USE OF IN-EAR ACCELEROMETERS TO SIGNAL CONCUSSION

THE USE OF IN-EAR ACCELEROMETERS TO SIGNAL CONCUSSION - PowerPoint Presentation

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THE USE OF IN-EAR ACCELEROMETERS TO SIGNAL CONCUSSION - PPT Presentation

ICMS 2015 Stephen E Olvey MD Associate Professor of Clinical NeurologyNeurosurgery University of MiamiMiller School of Medicine Founding Fellow FIA Institute for Motor Sports Safety and Sustainability ID: 536732

accelerometers ear head linear ear accelerometers linear head dof data car miami concussion impacts system resultant impact crashes acceleration

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Slide1

THE USE OF IN-EAR ACCELEROMETERS TO SIGNAL CONCUSSION

ICMS 2015

Stephen

E. Olvey, M.D.

Associate Professor of Clinical Neurology/Neurosurgery

University of Miami-Miller School of Medicine

Founding Fellow FIA Institute for Motor Sports Safety and Sustainability

CMO Formula E. United

StatesSlide2
Slide3

HISTORY

CHALLENGE: TO PLACE MINIATURE TRIAXIAL ACCELEROMETERS INTO

THE EAR PIECES DRIVERS USE TO COMMUNICATE WITH THEIR CREWSSlide4

HISTORY

CONCEPT INTRODUCED AT A MEETING IN SEBRING, FLORIDA, 1999

AMONG THOSE PRESENT WERE: John Melvin

Ted Knox

Doug Hill

Representatives from:

Endevco

Delphi

Racing Radios

Ford

GMSlide5

HISTORY

Project was initially met with much skepticism.

Second meeting held one month later.

Endevco

took the initiative and designed the first accelerometers.

Delphi then improved the original model and these were used in

the first tests.

Initial tests performed at Wright-Patterson AFB a short time later.Slide6

PROGRESS

In 2003, we utilized, for the first time, ear-piece accelerometers

to measure head motion with five degrees of freedom

during crashes. Data coupled with car crash recorder

data Slide7
Slide8

0 Degree Rear Impact, with and without helmet TIME: 20 msSlide9

THE DEVELOPMENT OF A METHOD TO MEASURE HEAD

ACCELERATION AND MOTION IN HIGH-IMPACT CRASHES

Stephen E. Olvey, M.D.

Department of Neurological

Surgery, University of Miami

School of Medicine, Miami, Florida

Ted Knox, Ph.D.

Biodynamics and Acceleration

Branch, Air Force Research

Laboratory, Wright-Patterson Air Force Base, Ohio

Kelly A. Cohn, R.N., M.S.

The Miami Project to Cure

Paralysis, University of Miami

School of Medicine, Miami, Florida

Reprint requests:

Stephen E. Olvey, M.D.,

Department of Neurological

Surgery, University of Miami School of Medicine, 1095 N.W. 14th Terrace (D4-6), Miami, FL 33136.

Neurosurgery-2004Slide10

PLACEMENT INTO AN ACTUAL RACE CARE DELAYED DUE TO

ARGUMENTS OVER VALIDITY AND ACCURACY.

- Uncoupling

- Only 5 DOF

- Too much artifact

- Electrical Interference

ALL ARGUMENTS EVENTUALLY DISPELLED OVER 1 YEAR Slide11

INITIAL IN-CAR TESTS DONE AT MID-OHIO AND

HOMESTEAD SPEEDWAYS IN 2001-2002 WITH GOOD

RESULTS OBTAINED.

SIMULTANEOUSLY, CADAVER TESTS WERE DONE AT WAYNE

STATE UNIVERSITY COMPARING HEAD WITH EMBEDDED

ACCELS. VS. THE EAR PIECE ACCELS. < 1% VARIATION.

IN 2004, SEVERAL DRIVERS TRIALED THE SYSTEM

BY 2012, ACCELEROMETERS WERE IN ALL OF THE DRIVERS.Slide12
Slide13

PARALLELL STUDIES BEGAN IN FOOTBALL IN 2003 SPURRED BY THE SIGNIFICANT INCIDENCE OF

CONCUSSION AND THE DISCOVERY OF POSSIBLE LONG TERM EFFECTS.

PELLMAN et al. USED HIGH SPEED

VIDEO FROM GAMES AND RECREATED CONCUSSIVE IMPACTS USING AN INSTRUMENTED HYBRID III DUMMY WITH THE VELOCITIES AND ANGLES OF IMPACT COMING FROM GAME FILMS AND THE CLOCK.Slide14

NFL SPONSORED STUDY

Pellman

/

Vianno

;

Neurosurgery, 2003 53(4), 799-812

25/31 Concussive

impacts; nominal linear

accel

. 79g, (SI 300, HIC 250) and peak rotational acceleration 5757 rad/s^ Values felt too conservative at the time(SI and HIC were derived in the 1960’s using linear accelerationsto determine how much force it took to cause a linear skull fx. in a cadaver skull.Rotational thresholds were determined on primates while studying concussion and DAI) Slide15

DEVELOPMENT OF THE “HITS” SYSTEM AT

VIRGINIA TECH, 2005

DUMA, ET AL: HEAD IMPACT TELEMETRY SYSTEM (HITS)

ACCELEROMETERS PLACED IN WAFERS LOCATED BETWEEN

HELMET LINER AND PLAYER’S HEAD

1. UNCOUPLING WITH HELMET AND HEAD

2. 5 DOF NOW WITH > 27,000 IMPACTS, NOMINAL INJURY VALUE REPORTED WAS 165 g WITH HIC OF 400. (MUCH > NFL STUDY) Slide16

POTENTIAL DIFFICULTY WITH BOTH HITS AND INDY SYSTEM

CONCUSSION

IS PRIMARILY CAUSED BY ROTATIONAL

INJURY

ROTATION IS NOT MEASURED WITH ONLY 5 DOF, NEED 6 DOF

IN ORDER TO GET ROTATION ABOUT THE “Z” AXISSlide17
Slide18

FIRST STUDY WITH 6 DOF – 2007

(Non-peer reviewed trial)

12 ACCELEROMETERS USED IN 6 PAIRS PLACED ORTHOGONALLY INSIDE

THE HELMET TANGENTIAL TO THE HEAD COG TO GIVE 6 DOF Slide19

HISTORY

CONCEPT AT FIRST MET WITH SKEPTICISM, 1 MONTH LATER

MEETING HELD IN MIAMI WITH PLANS IN PLACE

A

EXPANSION OF THE ORIGINAL HITS SYSTEMSlide20
Slide21
Slide22
Slide23

RESULTANT LINEAR ACCELERATIONSlide24

PEER REVIEWED STUDY WITH 6 DOF COMPLETED, 2009

-1712 IMPACTS ANLYZED (none concussed)

FOUND THAT:

Football players routinely have impacts of

< 40g and rotational accelerations of < 3000 rad/sec^

Slide25

RESULTS

(DATA REPORTED AS RESULTANTS ONLY FOR LINEAR ACCELERATIONS)

- 10% Impacts > 40g, 11impacts were > 79g

- 143 Impacts > 3000rads/sec^, 14 > 5757 rad/sec^

- Range: linear 9 – 135g; angular 107 – 9922 rad/sec^

- >3000 rad/sec^ more common around “z” axis as were

the higher linear acceleration values (No documented concussions) Slide26

INDY CAR STUDY - 2015

In-ear accelerometers have been in use in Indy Car racing in

some form since 2003.

Different companies have made improvements to the system

with a stable platform in use since 2012

I was asked to review and report on all available post –crash

data from years 2012, 2013, and 2014Slide27

METHOD

CONCUSSION IS NOT FELT TO EVER OCCUR BELOW A HEAD

ACCELERATION OF 50g. THEREFORE, ONLY CRASHES

WITH A MAXIMUM RESULTANT VALUE OF > 50g WERE

EXAMINED.

ONCE THESE CRASHES WERE TABULATED, MEDICAL

DATA WAS OBTAINED THAT REVEALED WHAT INCIDENTS

RESULTED IN A DOCUMENTED CONCUSSION TO THE DRIVER

NOTE:

Many concussions are missed!Slide28

FINDINGS

TOTAL NUMBER OF CRASHES 43

2012 = 16

2013 = 13

2014 = 14Slide29

REPORTED: 10g INCREMENTS OF HIGHEST

RECORDED RESULTANT FOR EITHER EAR

50-60g = 16 160-170 = 1

60-70g = 6 170-180 = 1

70-80g = 4 180-190 = 0

80-90g = 2 190-200 = 0

90-100 = 2 200-210 = 1

100-110 = 0 210-220 = 1

110-120 = 1 220-230 = 0

120-130 = 1 230-240 = 0

130-140 = 1 240-250 = 0140-150 = 3 > 250 = 1150-160 = 2Slide30

DOCUMENTED CONCUSSUIONS 2012-2014

TOTAL NUMBER = 5, 3 WERE WITHOUT RECORDED DATA

(usually related to the wiring)

ONLY 2 CONCUSSED DRIVERS WITH COMPLETE DATA

Slide31

SUBJECT 1

RIGHT EAR = 138.92g LEFT EAR = 154.11g

CAR WITH LINEAR RESULTANT < 5g, SUSTAINED

NO RECORDED DAMAGE; DRIVERWAS HIT IN

CHIN BY DEBRIS FROM ANOTHER CARSlide32
Slide33

SUBJECT 2

RIGHT EAR RESULTANT = 168.92g, LEFT EAR = 171.93g

CAR WITH 3 AXIS RESULTANT VALUE = 68.99g

(Right frontal impact of 56 deg.)Slide34

CONCLUSIONS:

DATA FROM EAR ACCELEROMETERS IS

REPRODUCIBLE.

2. INJURY THRESHOLDS CAN BE ESTABLISHED.

3. TOO FEW CONCUSSIONS TO BE USEFUL IN

EQUIPMENT DESIGN.

4. 6 DOF NOT NEEDED TO ACCURATELY ASSESS

CONCUSSION RISK.

5. SETTING A TRIGGER THRESHOLD OF > 80g FOR MANDATORY TESTING MAKES SENSE.6. EAR ACCELS. DETECT HIGH g IMPULSIVE LOADING. Slide35
Slide36

THANK YOU