Transcript Document

Longitudinal fNIRS Stroop Study of Adult Traumatic
Brain Injured Patients in Post-Acute Treatment
Matthew Cloud, BS1,2; Jana Downum, MA, BCB, CBIS1; Hanli Liu, PhD2; Patrick M. Plenger, PhD, ABPP1
1Pate
Introduction: Traumatic brain injury (TBI) and stroke are
the leading causes of adult disability and death
worldwide1. The Stroop test is used to determine the
selective attention of subjects. TBI patients, one year
post injury, undergoing Stroop studies with functional
Magnetic Resonance Imaging (fMRI) show increased
activation of left dorsolateral prefrontal (DLPFC) and left
posterior parietal cortices2.
Also functional Near-Infrared Spectroscopy (fNIRS) of
healthy subjects after exercise in comparison to control
groups for interference tasks shows significant left
DLPFC activity3. To determine the effects of TBI on the
inhibitory response to distraction within one year of
injury, a two part Stroop task was performed by patients
receiving multidisciplinary therapy at a post-acute
treatment facility.
Fig 1) 3x11 Optode Array5
University of Texas Arlington
Fig 2) Probe placement5
Controls
1st Week
3rd Week
5th Week
Patients
1st Week
3rd Week
5th Week
Fig 3) Interference task minus simple task (B-A) p-value=0.05, no correction;
Control Group (n=14, 13, 13); Patient Group (n=16, 14, 16)
18
16
14
% Error rate
Methods & Approach : A Hitachi ETG-4000 fNIRS
system with a 3x11 array was used on Sixteen patients
(41 +/-15.0 years, 86% Male) in multidisciplinary postacute rehabilitation 2 to 13 months post TBI and 14
controls (38 +/-10.8 years, 57% Male) underwent
three sessions over a one month period during which
fNIRS measures were taken while they performed a
modified Stroop task. For Task A the subject spoke
the color of a presented dot. For Task B the
subject spoke the font color of an incongruent word.
Each run started with a 10 s rest followed by an
ABBABA task pattern with 25 images per block at a
rate of 1 image/s, and a rest period of 30 s.
Subjects repeated the run two weeks, and four weeks
after the original run.
Rehabilitation,
2The
12
10
Control A
Control B
Patient A
Patient B
8
6
4
2
0
0
1
2
3
Session (two weeks between session)
4
Fig 4) Stroop Error Rate by Task with Standard Error
For presentation at the 2nd Biennual Functional Near-Infrared Spectroscopy Conference
Funding: Pate Rehabilitation Endeavors, Inc.
Results & Summary: NIRS-SPM version 4 with wavelet-MDL
and hemodynamic response functions were used for analysis.
Individual false positives improved with Euler characteristics4,
but group analysis with no correction limited false negatives.
Figure 3 shows subtraction of Task B from A to reveal activity
which is specific to the interference task. Over a one month
period, the control group shows a decrease in bipolar
frontopolar cortex activity while the patient group shows an
increase in left DLPFC activity. The lack of significant activity
shown in patient group week 1 is possibly a result of saturation
during Task A for patients with significant dispersed activity and
may indicate a lack of inhibitory response. Week 5 is
consistent with previous patient studies one year after injury.
In addition the percent rate of error (Fig 4) for the simple task
for patients and controls were equivalent within standard error.
However the interference task showed a greater rate of
improvement for patients (-5.63) than controls (-1.98.)
Therefore, left DLPFC increased activity may be an indicator of
gradual return to normal brain function from receiving
multidisciplinary therapy.
References:
1U.S. Centers for Disease Control and Prevention
2Soeda, A, et al., “Cognitive Impairment After Traumatic Brian Injury: a Functional
Magnetic Resonance Imaging study using the Stroop Task,” Neuroradiology 47:501-506,
2005.
3Yanagisawa, H, et al., “Acute Moderate Exercise Elicits Increased Dorsolateral Prefrontal
Activation and Improves Cognitive Performance with Stroop Test,” NeuroImage 50:17021710, 2010.
4Li, H., et al., “Lipschitz Killing curvature based expected Euler characteristics for p-value
correction in fNIRS,” J. Neurosci. Meth. 204, 61-67, 2012.
5 Hitachi Medical Systems Europe 1994, 2012
6Ye, J. C., et al., “NIRS-SPM: Statistical parametric mapping for near-infrared spectroscopy,”
NeuroImage 44, 428-447, 2009.