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conditions and the mice were allowed to acclimate for a period of 5
minutes followed by another pair of trials. After the completion of
all 4 trials the mouse was returned to the home cage and the next
mouse was tested. On subsequent days this testing was repeated with
the rotation of the drum increased in a range from 2 to 5 rpm. All
trials were recorded with Noldus Ethovision XT.
Results:
Optomotor testing and optimization revealed a non-ran-
dom, quantifiable optokinetic response of the mice which was found
by excluding the portions of the trial where the mouse was in motion
and by quantifying the angular rate of rotation of the head of each
mouse.
Conclusions:
By varying the resolution of the stripes we were able
to increase the difficulty of the task and determine the optimal con-
ditions for eliciting an optokinetic response in healthy mice capable of
discriminating subtle vision deficits. Varying the rotation rate of the
optomotor drum also allowed us to determine the optimal speed for
eliciting the optokinetic response. The optimized assay will allow us
to accurately assess the functional outcome of potential therapeutics
for the treatment of TBI-induced visual dysfunction.
Keywords: Optokinetic, Neurobehavior, Optomotor, Animal model,
Vision
D2-05
INJURY PROFILES, DEMOGRAPHY AND REPRESENTA-
TIVENESS OF PATIENTS WITH TBI ATTENDING A RE-
GIONAL EMERGENCY DEPARTMENT
Olli Tenovuo
1
, Henna Ala-Seppa¨la¨
1
, Iiro Heino
2
, Janek Frantze´n
2
, Ari
Katila
3
, Jussi Posti
2
, Riikka Takala
3
1
Turku University Hospital, Rehabilitation and Brain Trauma, Turku,
Finland
2
Turku University Hospital, Neurosurgery, Turku, Finland
3
Turku University Hospital, Perioperative Services, Intensive Care,
and Pain Management, Turku, Finland
Introduction:
A common cause for conflicting results in studies with
TBI is the variability in study populations. Several large current in-
ternational efforts try to recruit unselected samples of patients with
TBI attending the participating hospitals. We describe our results and
experiences from the prospective recruitment during the TBIcare
study.
Methods:
TBIcare was an international effort to develop diag-
nostic modelling for TBI. During the study we aimed at recruiting
200 largely unselected adult patients attending the regional emer-
gency department of the Turku University Hospital, Finland. Ex-
clusion criteria were age
<
18 yrs, severe pre-injury disability, blast/
penetrating injury, more than 2 weeks from the injury, not living in
the district, not speaking native language, and uncertain diagnosis of
TBI. To be included a need for acute head CT (NICE-criteria) was
required.
Results:
Of the 632 potentially eligible patients with TBI or sus-
pected TBI during the study we recruited 203 patients. From those
who were left out, 53% were because of predefined exclusion criteria
and 47% due to logistic/communication reasons. Age
<
18 yrs (20%),
uncertain TBI diagnosis (17%), and not living in the area (14%) were
most common groups of exclusion. Lack of information for the re-
search group before discharge was the most common cause for being
left out (45%). The final study group had more men that the total
eligible population (p
=
0.008) but no other differences in demo-
graphics or injury mechanisms were found.
Conclusions:
A lack of prospective 24/7 recruitment by the re-
searchers may easily leave out a significant number of the patients and
cause unpredictable bias in the representativeness of the sample.
Uncertainty about the diagnosis of TBI is common.
Keywords: traumatic brain injury, demographics, representative-
ness
D2-06
ANALYZING CONCUSSION SCORE CRITERIA FOR VINYL
NITRILE FOAM AND MICROLATTICE MATERIAL USING
A ONE-DIMENSIONAL MODEL
Aditya Ponnaluri
1
, Igor De Rosa
5
, Bamidele Ali
6
, Joseph Severino
5
,
Alan Jacobsen
6
, Larry Carlson
5
, Christopher Giza
2–4
1
UCLA, Mechanical and Aerospace Engineering, Los Angeles, USA
2
UCLA, Brain Injury Research Center, Los Angeles, USA
3
UCLA, Department of Neurosurgery and Division of Pediatric
Neurology, Los Angeles, USA
4
UCLA, Mattel Children’s Hospital, Los Angeles, USA
5
UCLA, Materials Science and Engineering Department, Los Angeles,
USA
6
Architected Materials, Architected Materials, Ventura, USA
Biomechanics of sports concussions is an important topic of research
in the modeling community. In football, lower concussion proba-
bilities are associated with decreased accelerations experienced by
the brain after an impact. Studies using Head Impact Telemetry
System (HITS) and the Hybrid III System (HIII) have calculated
head injury criterion (HIC) and severity index (SI) scores, which
have been used to estimate risk for concussion. To develop a rapid
throughput system for evaluation of different helmet material
properties, we opted for a simple 1D model that includes the helmet
shell, padding, skull, and brain with springs and dashpots between
components, similar to that developed by [1]. Solving the multiple
degree-of-freedom (DOF) mass-damper-spring differential equations
can compute the acceleration curves following a blunt impact. We
evaluate the HIC and SI scores using this methodology on the vinyl
nitrile (VN) foam used widely in sports helmets and compare them
with a microlattice (ML) padding developed by Architected Mate-
rials and UCLA. The ML load-deflection curves show a 22% de-
crease in peak force for the same energy absorption when compared
with VN foam. The unique structure of the ML leads to increased
energy absorption and damping coefficients under hysteresis tests
and are related to decreased HIC and SI scores with minor changes
in peak brain accelerations(C
=
100Ns/m HIC
=
154 PeakAcc
=
108
m/s^2, C
=
1000Ns/m HIC
=
67 PeakAcc
=
110m/s^2). A 1D-model
with parameters fit from experimental padding data can help drive
helmet padding designs to lower the probability of sports concus-
sions.
Support: NFL-GE; UCLA Steve Tisch BrainSPORT program, Jo-
seph Drown Foundation
[1]Honarmandi and Sadegh. ‘‘Modeling and Impact Analysis of
Football Helmets: Toward Mitigating mTBI.’’
ASME 2012
Keywords: Modeling, Bioengineering, Concussion
D2-07
A SINGLE CONCUSSIVE BRAIN INJURY TRANSIENTLY
DISRUPTS HOME CAGE ACTIVITIES IN MALE AND FE-
MALE C57BL/6J MICE
Laura Tucker
2,1
, Amanda Fu
2,1
, Jiong Liu
2,1
, Joseph McCabe
2,1
A-102