Do the blind have a more acute sense of smell?

Last Updated: Apr 27, 2010, 00:00 AM IST

Toronto: Debunking the age-old myth that the
blind have a more acute sense of smell than the sighted, a new
study claims that vision loss simply makes blind people pay
more attention to how they perceive smells.

According to Mathilde Beaulieu-Lefebvre, a graduate
student from the University de Montreal, who led the study:
"If you enter a room in which coffee is brewing, you will
quickly look for the coffee machine.

However, "a blind person entering the same room will only
have the smell of coffee as information. That smell will
therefore become very important for their spatial
representation," Beaulieu-Lefebvre said.

For the research, the team performed a three step study
in which 25 people, 11 of whom were blind from birth, were
tested.

The participants were asked to answer a questionnaire and
were also subjected to two experiments. In the first
experiment, they were made to differentiate 16 perfumes using
an olfactometer and in the second one, they were asked to
identify three smells: of a rose, vanilla and butanol (a sweet
alcohol), using a tomodensitometer.

Using functional imagery, the team determined that the
blind use their secondary olfactory cortex more than the
sighted when they smell. They also use the occipital cortex,
which is normally used for vision.

"That`s interesting because it means the blind are
recuperating that part of their brain," said Maurice Ptito, a
professor at the University de Montreal School of Optometry.

"We`re not speaking of recycling per se, yet that part of
the brain is reorganised and used otherwise," Ptito said.

The study could lead to concrete applications in the
re-adaptation of the blind.

"For instance, smells are very peculiar in shopping
centers. A hair salon, a pharmacy and a clothing store each
have their own distinctive scent. We could easily foresee
developing re-adaptation programs for getting around in such
places," Beaulieu-Lefebvre said.

PTI