Using optical brain imaging, Bloorview researchers decode preference with
80 per cent accuracy
TORONTO, Feb. 10 /CNW/ - Researchers at Canada's largest children's
rehabilitation hospital have developed a technique that uses infrared light
brain imaging to decode preference - with the goal of ultimately opening the
world of choice to children who can't speak or move.
In a study published this month in The Journal of Neural Engineering,
Bloorview scientists demonstrate the ability to decode a person's preference
for one of two drinks with 80 per cent accuracy by measuring the intensity of
near-infrared light absorbed in brain tissue.
"This is the first system that decodes preference naturally from
spontaneous thoughts," says Sheena Luu, the University of Toronto PhD student
in biomedical engineering who led the study under the supervision of Tom Chau,
Canada Research Chair in pediatric rehab engineering.
Most brain-computer interfaces designed to read thoughts require
training. For example, in order to indicate yes to a question, the person
needs to do an unrelated mental task - such as singing a song in their head.
The nine adults in Luu's study received no training. Prior to the study
they rated eight drinks on a scale of one to five.
Wearing a headband fitted with fibre-optics that emit light into the
pre-frontal cortex of the brain, they were shown two drinks on a computer
monitor, one after the other, and asked to make a mental decision about which
they liked more. "When your brain is active, the oxygen in your blood
increases and depending on the concentration, it absorbs more or less light,"
Luu says. "In some people, certain parts of the brain are more active when
they don't like something, and in some people they're more active when they do
After teaching the computer to recognize the unique pattern of brain
activity associated with preference for each subject, the researchers
accurately predicted which drink the participants liked best 80 per cent of
"Preference is the basis for everyday decisions," Luu says. When children
with disabilities can't speak or gesture to control their environment, they
may develop a learned helplessness that impedes development.
In future, Luu envisions creating a portable, near-infrared sensor that
rests on the forehead and relies on wireless technology, opening up the world
of choice to children who can't speak or move.
Her work is part of Tom Chau's body-talk research, which aims to give
children who are "locked in" by disability a way to express themselves through
subtle body processes like breathing pattern, heart rate and brain activity.
Luu notes that the brain is too complex to ever allow decoding of a
person's random thoughts. "However, if we limit the context - limit the
question and available answers, as we have with predicting preference - then
mind-reading becomes possible."
Bloorview Kids Rehab is Canada's largest children's rehabilitation
hospital, fully affiliated with the University of Toronto. Visit
For further information:
For further information: Media Contact: Louise Kinross, Bloorview Kids
Rehab, (416) 424-3866, pager (416) 589-8826