The Effects of Explosive Blast as Compared to Post-Traumatic Stress Disorder on Brain Function and Structure
| Status: | Completed |
|---|---|
| Conditions: | Hospital, Neurology, Psychiatric |
| Therapuetic Areas: | Neurology, Psychiatry / Psychology, Other |
| Healthy: | No |
| Age Range: | 20 - 50 |
| Updated: | 4/2/2016 |
| Start Date: | April 2008 |
| End Date: | March 2012 |
| Contact: | Scott R Sponheim, Ph.D. |
| Email: | sponh001@umn.edu |
| Phone: | 612-467-3916 |
Brain injury from explosive blast is a prominent feature of contemporary combat. Although
protective armor and effective acute medical intervention allows soldiers to survive blast
events, a growing number of veterans will have disability stemming from blast-related neural
damage. Soldiers also return from combat with psychological disabilities caused by traumatic
war events. The clinical presentation of individuals with blast-related neural damage and
post-traumatic psychopathology are markedly similar and thus a clear description of the
direct consequences of explosive blast is complicated by the emotional and cognitive
sequelae of psychological trauma. We will use sophisticated measures of neural function and
structure to characterize brain injury from explosive blasts in a sample of Operation Iraqi
Freedom (OIF) National Guard soldiers who returned from deployment in the fall of 2007.
Survey data gathered near the end of deployment indicated that over 50% of the brigade had
been exposed to direct physical effects of explosive blasts. To fully characterize the
effects of blast on the brain and differentiate them from post-traumatic stress disorder, we
will contrast groups of soldiers exposed to blast and with groups experiencing
post-traumatic stress disorder. This investigation will improve the characterization of
blast-related traumatic brain injury, describe the essential features of the condition in
terms of neural function and structure to inform diagnosis, and characterize mechanisms of
recovery after blast-related neural injury to allow the creation of interventions that
return soldiers to maximum levels of functioning.
protective armor and effective acute medical intervention allows soldiers to survive blast
events, a growing number of veterans will have disability stemming from blast-related neural
damage. Soldiers also return from combat with psychological disabilities caused by traumatic
war events. The clinical presentation of individuals with blast-related neural damage and
post-traumatic psychopathology are markedly similar and thus a clear description of the
direct consequences of explosive blast is complicated by the emotional and cognitive
sequelae of psychological trauma. We will use sophisticated measures of neural function and
structure to characterize brain injury from explosive blasts in a sample of Operation Iraqi
Freedom (OIF) National Guard soldiers who returned from deployment in the fall of 2007.
Survey data gathered near the end of deployment indicated that over 50% of the brigade had
been exposed to direct physical effects of explosive blasts. To fully characterize the
effects of blast on the brain and differentiate them from post-traumatic stress disorder, we
will contrast groups of soldiers exposed to blast and with groups experiencing
post-traumatic stress disorder. This investigation will improve the characterization of
blast-related traumatic brain injury, describe the essential features of the condition in
terms of neural function and structure to inform diagnosis, and characterize mechanisms of
recovery after blast-related neural injury to allow the creation of interventions that
return soldiers to maximum levels of functioning.
Background: The clinical presentation of individuals with blast-related brain injury and
post-traumatic stress reactions can be markedly similar and thus a clear description of the
direct consequences of explosive blast is complicated by the emotional and cognitive
sequelae of psychological trauma. The inability to clearly separate the basis of symptoms
for the two conditions has hampered clinicians in prescribing effective treatments that
return soldiers to maximal functioning. Measures that directly assess neural disruption may
be employed to differentiate blast-related brain injury from post-traumatic psychopathology
and guide effective intervention..
Objective/Hypothesis: We propose to use quantitative indices of brain electrical activity
and diffusion tensor imaging (DTI) to characterize the effects of blast injury on brain
function and structure. We hypothesize that Operation Iraqi Freedom (OIF) soldiers injured
by explosive blast will be distinguishable from those with post-traumatic stress disorder
(PTSD) on measures of brain function and structure. Specifically, blast exposure will be
associated with diminished P3a amplitudes to target stimuli during sustained attention and
diminished lateralized frontal potentials during recognition of previously presented words.
Individuals with PTSD will exhibit normal amplitudes of P3 and lateralized frontal brain
potentials. Blast affected soldiers will also have compromised white matter integrity in
supracallosal, inferior frontal, and superior frontal brain regions while PTSD will not be
associated with these structural abnormalities. Finally, functional brain anomalies (e.g.,
P3a), and frontal white matter fractional anisotropy will be associated with the adaptive
functioning of soldiers.
Specific Aims: Using advanced quantitative analyses of electroencephalogram recordings we
will determine the nature of functional neural anomalies related to sustained attention and
memory deficits evident after injury from blast. We will determine white matter anomalies
that are unique to blast injury as compared to PTSD. We will also determine which aspects of
blast-related functional and structural brain abnormalities are associated with adaptive
functioning in post-deployment. The long-term goals for the proposed program of research are
to improve the characterization of traumatic brain injury (TBI) due to blast, describe its
essential features in terms of neural function and structure to improve diagnosis, and
characterize mechanisms of recovery after blast-related neural injury to facilitate the
creation of interventions that target pathophysiology.
Study Design: In May of 2007 over 2650 Minnesota National Guard troops of the 1/34 BCT
completed a within-theatre survey on health, exposure to blast, and traumatic events.
Fifty-one percent of surveyed troops reported being close enough to an explosive blast that
they felt a heat or pressure wave, had trouble hearing, or had subsequent problems with
attention or memory. The proposed study will be carried out over a four-year period and
include a total of 180 subjects. To determine the neural consequences of blast exposure we
will compare the functional and structural brain characteristics of individuals from the
1/34 BCT who have blast injury, blast injury and PTSD, PTSD, and no blast injury or PTSD.
There will be 45 demographically similar subjects in each group.
post-traumatic stress reactions can be markedly similar and thus a clear description of the
direct consequences of explosive blast is complicated by the emotional and cognitive
sequelae of psychological trauma. The inability to clearly separate the basis of symptoms
for the two conditions has hampered clinicians in prescribing effective treatments that
return soldiers to maximal functioning. Measures that directly assess neural disruption may
be employed to differentiate blast-related brain injury from post-traumatic psychopathology
and guide effective intervention..
Objective/Hypothesis: We propose to use quantitative indices of brain electrical activity
and diffusion tensor imaging (DTI) to characterize the effects of blast injury on brain
function and structure. We hypothesize that Operation Iraqi Freedom (OIF) soldiers injured
by explosive blast will be distinguishable from those with post-traumatic stress disorder
(PTSD) on measures of brain function and structure. Specifically, blast exposure will be
associated with diminished P3a amplitudes to target stimuli during sustained attention and
diminished lateralized frontal potentials during recognition of previously presented words.
Individuals with PTSD will exhibit normal amplitudes of P3 and lateralized frontal brain
potentials. Blast affected soldiers will also have compromised white matter integrity in
supracallosal, inferior frontal, and superior frontal brain regions while PTSD will not be
associated with these structural abnormalities. Finally, functional brain anomalies (e.g.,
P3a), and frontal white matter fractional anisotropy will be associated with the adaptive
functioning of soldiers.
Specific Aims: Using advanced quantitative analyses of electroencephalogram recordings we
will determine the nature of functional neural anomalies related to sustained attention and
memory deficits evident after injury from blast. We will determine white matter anomalies
that are unique to blast injury as compared to PTSD. We will also determine which aspects of
blast-related functional and structural brain abnormalities are associated with adaptive
functioning in post-deployment. The long-term goals for the proposed program of research are
to improve the characterization of traumatic brain injury (TBI) due to blast, describe its
essential features in terms of neural function and structure to improve diagnosis, and
characterize mechanisms of recovery after blast-related neural injury to facilitate the
creation of interventions that target pathophysiology.
Study Design: In May of 2007 over 2650 Minnesota National Guard troops of the 1/34 BCT
completed a within-theatre survey on health, exposure to blast, and traumatic events.
Fifty-one percent of surveyed troops reported being close enough to an explosive blast that
they felt a heat or pressure wave, had trouble hearing, or had subsequent problems with
attention or memory. The proposed study will be carried out over a four-year period and
include a total of 180 subjects. To determine the neural consequences of blast exposure we
will compare the functional and structural brain characteristics of individuals from the
1/34 BCT who have blast injury, blast injury and PTSD, PTSD, and no blast injury or PTSD.
There will be 45 demographically similar subjects in each group.
Inclusion Criteria:
- A high level of posttraumatic stress will be operationally defined "moderate" levels
(a rating of 3 or more on a 1 to 5 scale) of the following symptoms according to Hoge
et al 4: one re-experiencing symptom, three avoidance symptoms, and two hyperarousal
symptoms. Staff will complete a screening interview via telephone in which the
potential participant answers questions from the Blast Exposure Screen. The Blast
Exposure Screen provides a comprehensive assessment of exposure to blast for the
duration of deployment. Blast events will be rated for physical effects (e.g.,
knocked off balance, physically thrown by blast) and after effects (i.e., memory
problems, headache) on the individual.
- Individuals who report memory lapses,
- Sensitivity to light or noise, headaches
- Difficulty with concentration shortly after the explosive blast and have any of the
same symptoms in the past month will be invited to participate in the study.
Exclusion Criteria:
- Participants will be excluded from the study if they manifest
- Current substance induced psychotic disorder or psychotic disorder due to a general
medical condition than TBI
- Current or past DSM IV defined substance dependence other than alcohol, caffeine, or
nicotine
- Current DSM IV substance abuse other than alcohol, caffeine, or nicotine
- A neurologic condition or DSM Axis I mental disorder prior to deployment
(predeployment data from a sample of soldiers from the 1/34 BCT yielded an estimated
rate of 5% of either PTSD or depression)
- Current or predeployment unstable medical condition that would likely affect brain
function (e.g., clear anoxic episode, cardiac arrest, current uncontrolled diabetes)
- Significant risk of suicidal or homicidal behavior
- Head injury from a source other than blast that resulted in loss of consciousness for
more the 15 minutes, post-traumatic amnesia, skull fracture, or hospitalization. The
screening interview will include questions to assess subjects with respect to the
above exclusion criteria. During the telephone contact subjects will complete a
screening for MRI protocols in order to exclude individuals who may have metal
fragments in their bodies.
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