146 / 198
irregular (variable, VT) spaced manner have divergent effects on
spinal cord plasticity. Six minutes of VT shock produces a mala-
daptive effect that inhibits adaptive plasticity. In contrast, extensive
training with FT shock promotes adaptive plasticity and reverses and
prevents the effects of variable spaced stimulation. Recently, our lab
provided evidence that the beneficial effects of fixed spaced shock
depend upon the central pattern generator (CPG) within the lumbar
enlargement. Given the role of the CPG in locomotor behavior, we
examined whether the temporal distribution of shocks would differ-
entially affect locomotion. Two minutes after an intrathecal injection
of serotonin (5HT) and NMDA, transected rats received 720 shocks in
either a VT (0.2–3.8 s) or FT (every 2 s; 0.5 Hz) shock pattern. Un-
expectedly, some subjects that received FT shock began to move their
tail in an oscillating fashion. Tail movements continued even after
shock ended and had moved at the same frequency. Further, exami-
nation of the tail movement during FT shock showed evidence of
anticipatory behavior (movements before next shock presentation),
reminiscent of temporal conditioning. Finally, the amount of stepping
was dependent on the temporal pattern received. We next examined
the effects of frequency (0.5, 2, or 8 Hz) on stepping and tail move-
ment. We found higher frequencies produced the highest amplitude
tail oscillations. Peak oscillation frequencies were observed at 0.5 and
2 HZ, regardless of stimulation frequency. Finally, we examined
temporal conditioning by systematically skipping a shock (producing
a 4 second pause) every 60 shocks during FT or VT shock. Tail
movements during the 4-second pause showed increased tail ampli-
tudes around the time of missed shock in the FT group. These ob-
servations provide evidence for an oscillatory mechanism underlying
the FT effect, which may be important for enhancing locomotor be-
havior.
Keywords: Tail Movement, Stimulation, Learning, Locomotion
D6-03
IMPACT OF AEROBIC EXERCISE ON COGNITIVE FUNC-
TIONS IN AN AGING MILD TRAUMATIC BRAIN INJURY
POPULATION: A PILOT STUDY
Camille Larson-Dupuis
1,2
, Florian Bobeuf
2
, He´le`ne Bergeron
2,3
,
Marie-E` ve Bourassa
2
, Gae¨lle Dumel
2
, Ve´ronique Pepin
2,4
, Louis De
Beaumont
2,3
1
Universite de Montreal, Psychology, Montreal, Canada
2
Hoˆpital du Sacre´-Coeur de Montre´al, Centre de recherche, Mon-
treal, Canada
3
Universite´ du Que´bec a` Trois-Rivie`res, Psychology, Trois-Rivie`res,
Canada
4
Concordia University, Exercise Science, Montreal, Canada
Effects of mild traumatic brain injuries (mTBI) are most evident
with aging, as mTBI victims are more at risk of experiencing mild
cognitive impairment. Moderate levels of physical activity have
been associated with a reduced risk of developing dementia. This
study aims to evaluate the impact of aerobic exercise in an aging
mTBI population.
Methods:
Twelve participants, aged between 55 and 70 and having
sustained a mTBI two to seven years earlier, were recruited to par-
ticipate in a three month physical exercise program. They were di-
vided into two groups: aerobic training (on cycle ergometers) and a
control group (stretching exercise). The participants’ cognitive func-
tions (neuropsychological testing) and physical condition (cycling
tests) were evaluated before and after the training.
Results:
The present study shows that participants from the aerobic
exercise group significantly improved their peak exercise capacity
(F
=
10.42, p
<
0.05)) and their performances on different neuropsycho-
logical tests, including the Trail Making Test Part B (F
=
2.57, p
=
0.14)
and the Brief Visuospatial Memory Test - Revised (F
=
7.69, p
<
0.05),
when compared to participants from the control group. Furthermore,
correlations drawn between these measures showed that the participants
who most improved their peak exercise capacity were also those who
showed the biggest improvements on neuropsychological measures:
Trail B (R
= -
.632, p
=
0.03) and BVMT-R (R
=
.411, p
=
0.18).
Conclusion:
These results demonstrate the importance of consid-
ering aerobic exercise as a relevant intervention to improve cognitive
functioning of mTBI patients.
Keywords: aerobic exercise, mild traumatic brain injury, neuro-
psychology, nonpharmacological intervention
D6-04
EFFECT OF COGNITIVE REHABILITATION IN IMPROV-
ING COGNITIVE SYMPTOMS AND DIFFUSION TENSOR
IMAGING FINDINGS FOLLOWING MILD TBI
Norhamizan Hamzah
1
, Veeramuthu V
2
, Narayanan NV
2
, Ramli N
3
,
Tan JH
1
, Sidhu AS
2
, Mustafa NA
4
, Delano-Wood L
5,6
, Cinna K
7
,
Mazlan M
1
1
UM, Rehabilitation Medicine, Kuala Lumpur, Malaysia
2
UM, Division of Neurosurgery, Kuala Lumpur, Malaysia
3
UM, Research Imaging Centre, Kuala Lumpur, Malaysia
4
UMMC, Rehabilitation Medicine, Kuala Lumpur, Malaysia
5
V A, San Diego Health System, San Diego, USA
6
UCSD, Psychiatry, San Diego, USA
7
Julius Centre UM, Social And Preventive Medicine, Kuala Lumpur,
Malaysia
Aim:
This study is to evaluate the effectiveness of cognitive reha-
bilitation therapy in the alteration of neuropsychological performance
and Diffusion Tensor Imaging (DTI) parameters in mild traumatic
brain injury (mTBI).
Method:
An interventional study of 6 months. MTBI patients with
normal computed tomography brain scan finding and had fulfilled
inclusion criteria, underwent structural DTI scan within 10 hours post
trauma and evaluated using Screening - Neuropsychological Assess-
ment Battery (S-NAB Form 1) within two weeks of injury. Patient
education session and self-monitoring of symptoms were im-
plemented, followed by individualized cognitive therapy, based on
baseline deficits of neurocognitive performance. Computerized ther-
apeutic rehabilitative tools were used, along with customized patient
items. Frequency of therapy is weekly with 3 months post injury
review of progress by using S-NAB (Form 2). At six months, all
participants underwent repeat DTI MRI scan and S-NAB and the
results compared with baseline.
Results:
15 patients with mTBI (mean age 27.12, SD 6.30) in the
treatment group underwent DTI scanning at an average of 12.1 hours
(SD 4.84) with neuropsychological performance assessment at an
average of 8.25 hours (SD 7.08) upon full GCS recovery. Results were
compared to 15 mTBI controls (who received standard treatment with
a mean age
=
28.15, SD 5.84). 86.8% of patients in the treatment
group completed the individualized cognitive therapy and 66.7% of
these patients made significant progress at 3 months post intervention.
Stepwise improvement of neurocognitive performance at both 3 and 6
months post trauma were observed with corresponding recovery in
few white matter tracts (66.7% in the treatment group and 40% in the
control group).
Keywords: cognitive rehabilitation, diffusion tensor imaging, mild
traumatic brain injury
A-110