Christine Beauchene is a mechanical
engineering doctoral student working
to help people maintain their working
memory.
As one of the latest winners of the
Paul E. Torgersen Graduate Student
Research Excellence Award, Beauchene
uses sound to influence the brain.
Specifically, binaural beats, a method
using two pure tones, with a small
frequency mismatch, delivered inde-
pendently to each ear.
To localize where sound is coming
from, the brain interprets the dif-
ference between the tones as a beat
frequency. “If we play 240Hz into the
right ear and 255Hz into the left ear,
we can see an increase in the power of
the frequency spectrum, of the mea-
sured brain recordings, at 15Hz - the
difference of the two tones. Using this
method, we can safely and noninva-
sively stimulate your brain at a desired
frequency,” she said.
Beauchene describes working mem-
ory as the system that allows us to
remember and manipulate information
in the presence of additional incoming
information. “However,” she said, “we
can only remember a certain number
of items for a short period of time.
For example, phone numbers were
originally 7 digits because experiments
showed that, on average, 7 was the
number of items people could hold in
working memory.”
Working memory capacity is depen-
dent upon synchronization between
regions of the brain, particularly the
frontal and parietal lobes located in the
front and in the upper back part of the
brain, respectively. Higher synchroni-
zation equates, on average, with higher
accuracy during a working memory
task.
Binaural beats can modulate syn-
chronization in the brain and boost
working memory capacity. Beauchene
is working to develop an experimental
system to tailor the frequency of the
binaural beat stimulus to each person
using closed-loop control. Currently,
nearly all therapeutic stimulation sys-
tems are open-loop “one-size-fits-all”
approaches. However, these methods
can prove not as effective because
each person’s brain responds slightly
differently to external stimuli, and can
change over time. The driving motiva-
tion for developing a closed-loop stim-
ulation system is to help populations
with large individual variability, such
as those with mild cognitive impair-
ment (MCI).
“Cognitive function decreases as a
function of time and in people with
MCI we see a steeper decrease than
you’d normally expect in healthy
adults,” Beauchene explained. “MCI
is considered to be an intermediate
step in the progression to Dementia”
without necessarily being an indicator
of Dementia or Alzheimers - but the
odds, Beauchene says, increase. “We
are trying to target people with MCI
because working memory is one of the
earliest cognitive functions to show
significant decline. We’re hoping that
if we can boost working memory then
we can potentially increase a person’s
quality of life.”
Before this research, no one had
studied the effects of binaural beats on
working memory and correlated the
changes seen in behavior to the chang-
es in the brain connectivity graphs, she
explained.
“The eventual goal of the project is to
develop a portable easy to use closed-
loop therapeutic system for MCI
patients for use whenever they want,”
she said.
For now, there is a lot of research to
be completed and Beauchene said she
hopes to develop better therapeutic
options for people suffering from
memory loss.