Does a Blind person have extra Hearing capacity? Author Mugambi Paul

Does a Blind person have extra Hearing capacity?
Author
Mugambi Paul

Generally speaking, persons who are not blind or vision impaired have unique assumptions and perceptions.
This is because they hold on believes that blind persons have they a higher level of hearing among the rest of the population.
There are many debates which have multifaceted answers on this topic.
On my journey on social inclusion I have been asked severally this question.
Different scholars and persons with lived experience of being blind
have evidently contributed to this debate. Whenever I am asked the question, do I have better hearing because I am blind? I say that if tested, my hearing is probably no better than anyone else’s,
but the difference is that I know how to use it.
Most people are fascinated by the fact that I can hear the presence of an obstacle, such as when I am approaching a wall or a post, opening a bag or something else on
the pavement. I explain this to be possibly air pressure, the lack of wind from a certain direction because of an obstacle, and also echoes from surrounding
sounds. I use this extra sense a lot and find it very successful. I often demonstrate it to sighted people who are really impressed with it.
Research has shown that people who are born blind or become blind early
in life often have a more nuanced sense of hearing, especially when it
comes to
musical abilities and tracking moving objects in space.
For decades scientists have wondered what changes in the brain might
underlie these enhanced auditory abilities. Now, two research papers
published from
the University of Washington, use functional MRI to identify two
differences in the brains of blind individuals that might be responsible
for their abilities
to make better use of
auditory information.
???There???s this idea that blind people are good at auditory tasks, because
they have to make their way in the world without visual information. We
wanted
to explore how this happens in the brain, ??? said Ione Fine, a UW
professor of psychology and the senior author on both studies.
Instead of simply looking to see which parts of the brain were most
active while listening, both studies examined the sensitivity of the
brain to subtle
differences in auditory frequency.
???We were???t measuring how rapidly neurons fire, but rather how
accurately populations of neurons represent information about sound,???
said Kelly Chang,
a graduate student in the UW Department of Psychology and lead author on
the
Journal of Neuroscience paper.
That study found that in the auditory cortex, individuals who are blind
showed narrower neural ???tuning??? than sighted subjects in discerning small
differences in sound frequency.
???This is the first study to show that blindness results in plasticity in
the auditory cortex. This is important because this is an area of the
brain that
receives very similar auditory information in blind and sighted
individuals,??? Fine said. ???But in blind individuals, more information
needs to be extracted
from sound ??? and this region seems to develop enhanced capacities as a
result. This provides an elegant example of how the development of
abilities within
infant brains are influenced by the environment they grow up in.???
The Proceedings of the National Academy of Sciences study examined how
the brains of
people who are born blind or become blind early in life ??? referred to as
???early blind??? individuals ??? represent moving
objects in space.
The research team showed that an area of the brain called the hMT+???
which in sighted individuals is responsible for tracking moving visual
objects ??? shows
neural responses that reflect both the motion and the frequency of
auditory signals in blind individuals. This suggests that in blind
people, area hMT+
is recruited to play an analogous role ??? tracking moving auditory
objects, such as cars, or the footsteps of the people around them.
The paper in the Journal of Neuroscience involved two teams ??? one at the
UW, the other at the University of Oxford in the United Kingdom. Both
teams measured
neural responses in study participants while participants listened to a
sequence of Morse code-like tones that differed in frequency while the
fMRI machine
recorded brain activity. The research teams found that in the blind
participants, the auditory cortex more accurately represented the
frequency of each
sound.
???Our study shows that the brains of blind individuals are better able to
represent frequencies,??? Chang said. ???For a sighted person, having an
accurate
representation of sound ins???t as important because they have sight to
help them recognize objects, while blind individuals only have auditory
information.
This gives us an idea of what changes in the brain explain why blind
people are better at picking out and identifying sounds in the environment.???
The Proceedings of the National Academy of Sciences study examined how
the brain???s ???recruitment??? of the hMT+ region might help blind people
track the motion
of objects using sound. Participants once again listened to tones that
differed in auditory frequency, but this time the tones sounded like
they were moving.
As has been found in previous studies, in blind individuals the neural
responses in area hMT+ contained information about the direction of
motion of the
sounds, whereas in the sighted participants these sounds did not produce
significant neural activity.
By using sounds that varied in frequency, the researchers could show
that in blind individuals, the hMT+ region was selective for the
frequency as well
as the motion of sounds, supporting the idea that this region might help
blind individuals track moving objects in space.
? These results suggest that early blindness results in visual areas
being recruited to solve auditory tasks in a relatively sophisticated
way? Fine said.
This study also included two sight-recovery subjects ??? individuals who
had been blind from infancy until adulthood, when sight was restored via
surgery
in adulthood. In these individuals, area hMT+ seemed to serve a dual
purpose, capable of processing both auditory and visual motion. The
inclusion of people
who used to be visually impaired lends additional evidence to the idea
that this plasticity in the brain happens early in development, Fine
said, because
the results show that their brains made the shift to auditory processing
as a result of their early life blindness, yet maintains these abilities
even
after sight was restored in adulthood.
According to Fine, this research extends current knowledge about how the
brain develops because the team was not only looking at which regions of
the brain
are altered as a result of blindness, but also examining precisely what
sort of changes ??? specifically, sensitivity to frequency ??? might explain
how early
blind people make sense of the world. As one of the study participants
described it, ???You see with your eyes, I see with my ears.???all in all I opine that blind persons utilize what the sighted persons don’t! to put it differently this studies have confirmed what I the response I give people when asked.
It is not that we have extra gift us Blind persons, but we utilize the maximum the hearing ability while the sighted use there vision.
Mugambi Paul is a public policy expert in diversity and inclusion.