Page 66 - NNS 2014 Abstract Book

B4-19
MEMORY AND THE HIPPOCAMPAL FORMATION FOL-
LOWING PEDIATRIC TRAUMATIC BRAIN INJURY
DeMaster, D.M., Johnson, C., Juranek, J., Ewing-Cobbs, L.
UTHealth-Science Center at Houston, Houston, USA
The goal of this research was to evaluate the impact of pediatric
traumatic brain injury (TBI) on nonverbal memory in relation to
volume of the hippocampus, a region of the brain that is critical for
declarative memory.
The present study examined children 6 weeks following a mild or
moderate TBI (TBI, n = 17) or extracranial injury (EI, n = 16). Ad-
ditionally, children, without a history of injury, were included as a
comparison group (n = 21). Children ranged in age from 8–15-years
with a mean age of 12-years for each of the groups.
Non-verbal memory was measured with the Visual Selective Re-
minding subtest of TOMAL2. Participants were asked to learn a
spatial dot pattern over the course of several trials. Scores for each
participant were normed for age. Structural brain data were acquired
on a Philips 3T MR scanner. Cortical and subcortical volumes were
first segmented with Freesurfer and then manually edited to ensure
accuracy of anatomy boundaries.
Controlling for total brain volume, a positive correlation was seen
between right hippocampal volume and performance on the Visual
Selective Reminding task for the TBI group, r14 = 0.56, p = 0.02, but
not the EI group or the comparison group. In the left hippocampus,
controlling for total brain volume, for TBI and EI groups a similar
trend was evident indicating that that individuals with larger left
hippocampal volumes showed higher scores on the Visual Selective
Reminding task (TBI: r14 = 0.45, p = 0.08; EI:, r13 = 0.49, p = 0.06).
This trend was not found in the comparison group.
Previous research indicates disruption of attention and memory in
children who have experienced TBI. The results of the current study
highlight the relation between hippocampal structure and memory
function during the subacute stage of recovery from mild to moderate
TBI. Longitudinal follow-up is needed to characterize changes in
hippocampal volume and integrity and their relation to the develop-
ment of memory following TBI.
Key words
childhood, hippocampus, learning, memory
B4-20
THE EFFECT OF BODY CHECKING AND HEAD CONTACT
RULE POLICY CHANGES ON CONCUSSION RISK IN
YOUTH ICE HOCKEY PLAYERS
Emery, C.A.1–3, Black, A.1–3, Krolikowski, M.1, Macpherson, A.4,
Hagel, B.1,2, Kang, J.1
1Sport Injury Prevention Research Centre, Faculty of Kinesiology,
University of Calgary, Calgary, Canada
2Alberta Children’s Hospital Research Institute, Faculty of Medicine,
University of Calgary, Calgary, Canada
3Hotchkiss Brain Institute, Faculty of Medicine, University of Cal-
gary, Calgary, Canada
4York University, Toronto, Canada
The objectives are 1) To determine if the risk of concussion differ for
11–12 year old ice hockey players in leagues where body checking is
permitted compared to leagues where it is not. 2) To examine the
effect of 2011 rule enforcement policy change ‘‘zero tolerance for
head contact’’ in reducing the risk of concussion in 11–14 year old ice
hockey players.
This is a mixed prospective and historical cohort study. Participants
included 11–14 year old ice hockey players from Alberta and 11–12 year
old players in Ontario (Canada). Independent variables included exposure
to policy permitting body checking, exposure before or after head contact
rule change, previous concussion, year of play, level of play, and player
position. The primary outcomes included all diagnosed concussions.
Based on multivariate Poisson regression analyses (adjusted for clus-
ter, exposure hours and other covariates), the concussion incidence rate
ratio (IRR) associated with policy allowing body checking was 2.83
(95% CI; 1.09 – 7.31). The concussion IRR associated with head contact
rule enforcement change in 11–12 year old players was 1.83 (95% CI;
1.18 – 2.86) and in 13–14 year old players was 2.74 (95% CI; 1.41 - 5.32).
The risk of concussion was 3-fold in 11–12 year old ice hockey players
in leagues where body checking is permitted. The head contact rule
enforcement policy change was not protective of concussion in 11–14
year old players. Referral bias related to a greater awareness of con-
cussions may contribute to the greater risk post-head contact rule change
despite consistent injury surveillance methodology. Policy disallowing
body checking is effective in preventing concussion in youth ice hockey.
Key words
concussion, epidemiology, ice hockey, policy, prevention, youth
B4-21
GRAY MATTER ABNORMALITIES IN PEDIATRIC MILD
TRAUMATIC BRAIN INJURY
Mayer, A.R. , Hanlon, F.M., Ling, J.M.
The Mind Research Network/Lovelace Biomedical and Environmental
Research Institute, Albuquerque, USA
Pediatric mild traumatic brain injury (pmTBI) is the most prevalent
neurological insult in children and is associated with both acute and
chronic neuropsychiatric sequelae. However, little is known about un-
derlying pathophysiology changes in gray matter diffusion and atrophy
from a prospective stand-point. Fifteen semi-acute pmTBI patients and
15 well matched healthy controls (HC) were evaluated with a clinical and
neuroimaging battery within 21 days of injury (mean = 14 days post),
with a subset of 10 patients and 10 controls returning for a second visit at
approximately 4 months post-injury. Clinical measures included tests of
attention, processing speed, executive function, working memory,
memory and self-reported post-concussive symptoms. Measures of dif-
fusion (fractional anisotropy (FA)) and atrophy were also obtained for
cortical and subcortical gray matter structures to characterize effects of
injury as a function of time. Results indicated that patients exhibited
decreased scores in the domains of attention and processing speed rela-
tive to controls during the semi-acute injury stage, in conjunction with
increased anisotropic diffusion in the left superior temporal gyrus and
right thalamus. Evidence of increased diffusion in these regions was also
present at 4 months post injury, with performance on cognitive tests
partially normalizing. In contrast, signs of cortical atrophy (Visit 2 cor-
tical thickness – Visit 1 cortical thickness) in bilateral frontal areas and
other left-hemisphere cortical areas only emerged at 4 months post-injury
for patients relative to HC. Current results suggest potentially differential
time-courses of recovery for neurobehavioral markers, anisotropic dif-
fusion and atrophy following pmTBI. Importantly, these data suggest that
relying on patient self-report or standard clinical assessments may un-
derestimate the time for true injury recovery.
Key words
abnormalities, neuropsychiatric, pediatric, pmTBI, TBI
A-66