Brain scans yield potential biomarker for PTSD
Research at Minneapolis VA used high-tech method for capturing neuron activity
February 2, 2010
Using a super-fast scanner that captures cross-talk between
groups of neurons in the brain, VA researchers and colleagues
have identified a potential biological marker of PTSD. The
findings appeared in the Jan. 20 Journal of Neural Engineering.
More than 70 veterans with PTSD and 250 people with no
mental diagnoses took part in the study. Using
magnetoencephalography (MEG), a noninvasive scan that
detects the tiny magnetic fields created when brain cells "fire,"
the researchers found a pattern of activity unique to PTSD. They
were able to differentiate between those with PTSD and healthy
controls with better than 90-percent accuracy.
"These findings document robust differences in brain function
between the PTSD and control groups that can be used for
differential diagnosis," said neuroscientist
Apostolos Georgopoulos, MD, PhD, who
led the study along with psychologist Brian
Engdahl, PhD. Both are with the Brain
Sciences Center at the Minneapolis VA
Medical Center and University of
Minnesota. The program is supported in
part by the American Legion.
Georgopoulos said MEG technology
could also be used to track disease
progression and the effects of therapy.
He noted that if the PTSD biomarker
holds up in further study, it may eventually
become one of the tools used by VA and the
Department of Defense to help determine
the medical status of service members and
veterans. This could apply especially when
symptoms of PTSD and brain injury
overlap, making it more difficult for doctors
to make accurate diagnoses.
The dome-shaped MEG scanner captures
bursts of neuron activity that last only
milliseconds. By comparison, a functional
MRI scan takes three seconds to make a
picture. When researchers overlay data from
MEG scans on a map of the brain, they can
show abnormalities—even subtle ones—as
patches of color, indicating precisely which
areas of the brain may be damaged.
The researchers found that in veterans
with PTSD, the working connections among
groups of brain cells were much stronger on
the right side of the brain, in an area known
as the parieto-temporal region.
Georgopoulos: "This shows a strong
miscommunication pattern of this area with
the rest of the brain. It is possibly related to
the permanent and painful memories that
are characteristic of PTSD. Veterans who
have recovered from PTSD still show this
pattern, but not as strongly."
In a smaller sample, veterans with mild
brain injuries—most commonly from
blasts—showed unfocused, diffused
miscommunication among many brain
regions, along with symptoms such as
headaches and dizziness. Blast-exposed
veterans who no longer had such symptoms
showed the same diffuse pattern. The
researchers say this may be evidence of the
long-lasting effects of some mild brain
injuries.
The group now plans to study larger
groups of veterans with PTSD as the sole
mental diagnosis and compare their MEG
scans with those of healthy volunteers. The
scientists already have further studies under
way with patients who have PTSD plus
brain injury or other problems, such as
depression or alcohol abuse.
The PTSD research follows other work in
which Georgopoulos' team used MEG to
detect distinct patterns for conditions
including Alzheimer's disease, multiple
sclerosis, schizophrenia and chronic
alcoholism.
This article originally appeared in the February 2010 issue of VA Research Currents.