Life’s trauma, physical or non-physical, can cause a flight-or-fight, or a
freeze, stress response. Most experience it. Some are crippled by it. So how can
stress, the body’s responses to what life throws at us, be assessed?
Wake Forest Baptist Medical
Center researchers think they have found a new approach. It
lies in going back to the source of the body’s stress responses, with
evaluation of brainwave asymmetry between the left and right sides of the brain’s
temporal lobe. The study is published online today in the journal Brain and Behavior.
fight-or-flight stress response, mediated by the sympathetic nervous system, creates
almost instantaneous physical reactions, including increased heart rate and
blood pressure, changes in attention, memory, and other bodily functions. However,
if a threat or trauma is especially severe, prolonged or overwhelming, stress
can also manifest as a freeze response.
This is mediated by the parasympathetic nervous system, with physical
reactions opposite of fight-or-flight.
stress responses are managed by the brain. Previous research shows the right
side of the brain is involved with sympathetic responses, while the left side
is associated with parasympathetic responses. Downstream effects can be
evaluated through recordings of blood pressure and heart rate, to evaluate
sympathetic versus parasympathetic nervous system influences on the
understanding of the close relationship between the brain and the heart is
vital to identifying better ways to manage stress. This study suggests a simple
method to evaluate central pathways in the brain that are involved in such
stress responses,” said principal investigator Charles H. Tegeler, M.D.,
professor of neurology at Wake Forest Baptist.
and his team performed five-minute recordings of heart rate and blood pressure
in 131 study participants, during the enrollment visit, to assess the effect of
the autonomic nervous system on the cardiovascular system. This was followed by
three minute scalp recordings of temporal lobe brain electrical activity, obtained
as part of a standard baseline brain assessment using High-resolution,
relational, resonance-based electroencephalic mirroring (HIRREM). For the one minute segment recorded with eyes
closed, brainwaves were analyzed to identify asymmetries in electrical
amplitudes at the higher frequencies.
showed that, among study participants with asymmetry in temporal lobe high
frequency electrical activity, those with right compared to left side asymmetry
had higher resting heart rates and other changes suggesting that the
cardiovascular system may be less capable of adapting to shifting circumstances.
believe the result is important because persistent stress is likely responsible
for a wide range of health and behavioral conditions. There is currently no simple
method to assess brain activation patterns for stress responses. Such data may inform better ways to mitigate
Funding for this project was
provided by research grants from The Susanne Marcus Collins Foundation, Inc.,
and the United States Army Research Office.
Also participating as
co-authors are Hossam A. Shaltout, Ph.D., Catherine L. Tegeler, B.S., from Wake
Forest Baptist’s Hypertension and Vascular Research Center and Department of
Neurology, respectively, as well as Lee Gerdes, and Sung W. Lee, M.D., M. Sc.
from Brain State Technologies, L.L.C., Scottsdale, Ariz.
More information regarding
this research program may be found at http://www.wakehealth.edu/Research/Neurology/HIRREM/.