Brew: When the first season of Stranger Things
debuted in 2016, the world renewed its
interest in the realm of sensory deprivation.
The use of one of these tanks in the latter half of the
series inspired many to seek out these curios and test them.
One surprising side effect of this renewed interest,
is that it allowed us to experience first-hand
what it might feel like to be “touch-blind”.
What do you think it would feel like for your
body to have no weight, no feeling of motion?
What would it feel like if your limbs were
someone else’s, yet you still controlled them?
It sounds super strange, but believe it or
not, there are people out there who will
collapse as soon as the lights go out!
Today’s episode concerns sensory perception,
and the experience of disability.
We’re just trying to educate and inform as best as we’re able.
As always, if you have any questions please ask your doctor.
And with that out of the way, let’s get into it!
There’s a small cylinder on a desk.
On top of it there is a small plastic ball,
and Sana, age 31, sits across from it.
A technician asks her to touch her nose, then touch the ball.
She does so easily.
The tech then asks her to do it again without looking, but
suddenly, it’s as if the ball has vanished from her reality.
She swings her arms around frantically, and
only touches the ball as if by accident.
She even struggles to touch the nose on her own face!
Grill: She couldn’t touch her own nose?
Pfft, how hard could it be to touch your own—oh no-se.
Brew: Her sister, Sawsen experiences
similar issues with her spatial reasoning.
She says that if the power goes out
at her home, she would fall over.
“It’s as if you had a blindfold and somebody turned you
several times, and then you’re asked to go in a direction.
The first few seconds, you don’t
know what direction you’re going in.”
In addition to that, the sisters’
sense of touch is also impaired.
Sawsen says that “Even with my eyes open, when
I touch the little ball, I don’t feel it”.
But they’re not the only ones!
An 18 year old woman from Calgary, Alberta could
only walk when she was looking at her feet.
If her eyes were closed, she would fall over.
In tests, after asking her to close her
eyes, doctors moved her fingers up and down.
Without looking at her hands, she had
no sensation of movement whatsoever.
She could not tell if someone was touching her.
Chill: Whoa, whoa wait, how does that work?
How can you not have a sense of touch, but
still be able to like, move your body and stuff?
Brew: That’s a great question!
Sana and Sawsen’s cases are so interesting because their
brains, muscles, and nervous system aren’t damaged.
The sisters were born with a genetic mutation that renders
one little gene that’s used to translate physical force on
the body into information that the brain can parse, inert.
It’s a condition that makes even just fishing your
keys out of your pocket into a rigged crane machine.
In Sawsen’s words, “I will take my hand out of the bag
thinking I’m holding something, and my hand is empty”.
A simple handbag or pocket can turn into a black hole.
This condition is immensely rare, and as of the end
of 2019, the National Institute of Health has only
identified 18 touch-blind individuals like Sana and Sawsen.
Alexander Chesler, a neuroscientist at the NIH, is excited
by these discoveries, describing this as “the equivalent of
identifying the first blind person, or the first deaf person”.
Grill: Okay, so they don’t have this gene or whatever?
What’s it even do?
Brew: It’s a gene that codes a
little ion channel called piezo2.
Grill: What’s an ion channel?
Sounds like a space gun.
Brew: My new assistant has got you covered!
Quiz?
Quiz: Hi, nice to meet you.
An ion channel is a pathway that facilitates the movement
of electrical signals between the brain and body.
Neurons fire electrical signals in your
brain, which travel along the nervous system.
Ion channels are there to make sure that those signals
can go to and from your nerves into your cells.
Ion channels like Piezo1 are implicated in our
blood-pressure regulating system, whereas piezo2
is linked to mechanosensation: our sense of
touch, and another sense, called proprioception.
Grill: Pro-what now?
Brew: It’s colloquially referred to as our “sixth
sense”, though technically we have more than that.
Quiz: There are four “senses” implicated
in an impairment like Sana and Sawsen have.
First is proprioception which is our
sense of joint and limb positioning.
It’s the feeling of how your arm feels
when it is in a specific position.
Second, is kinaesthesia which is our sense of motion.
Third, is our sense of force, or ability to match a
force exerted on our body, and lastly, is our sense of
change in velocity, or how well we can detect vibration.
When our bodies move, our muscles send electrical
signals to our brains, which combine the information
from those 4 senses into a model that we can understand.
When it works, we can just “feel” where we are in a space.
Brew: Sana and Sawsen were born with genetic mutations
that render their piezo2 channels non-functional,
which leaves their sense of proprioception inert.
If you want to get a feel for what this sense
is, we can try the same tests as doctors run.
If you would be so kind.
Quiz: Sure!
First, place an item on a flat surface in front of you.
With your eyes open, touch your nose and then touch the item.
Next, close your eyes and repeat it.
Your proprioceptive ability will determine
how well you can “feel” where your hand
is in relation to the rest of your body.
You can also test this by standing
up straight and closing your eyes.
Try to stand as still as you can for 30 seconds.
You should be able to feel your weight shifting
even if you begin to tip over, and correct yourself—
something that people with inactive piezo2 cannot do..
Brew: In addition to allowing us to “feel” where our bodies
are without looking, piezo2 also helps us feel gentle touch.
Like we mentioned earlier, when we think of
our 5 senses: hearing, smell, taste, sight, and
touch, however it’s probably more accurate to say
that those are our 5 basic categories of senses.
Touch is not a single sense, but
composed of many kinds of touch-senses.
Gentle touch is also affected by piezo2, and
without it, it’s very difficult to feel anything
less than heavy pressure against the body.
Chill: Whoa…. What if they’re at home and the power goes out?
Would they just fall over?
Can they go swimming in the dark?
How do they use their phones if they can’t
feel when they’re tapping the screen?
Brew: Like we mentioned earlier, there have
been less than 20 people diagnosed with a piezo2
impairment, so your guess is as good as mine.
It’s pretty complicated, but basically
it all comes down to muscles.
If you’re familiar with human anatomy, you know that
muscles are composed of long fibres stretched over
bones and joints which either stretch or contract
depending on where they’re located, and what is moving.
Inside some of the larger muscle fibres are muscle
spindles, which are wrapped spring like sensory fibres.
When you, say, throw a punch, these spindles stretch
and contract, sending electrical signals to your
brain that tells it how fast your arm is moving.
Piezo2 is a major part of the process of
transmitting this subtle information of how
the muscles are positioned to the brain.
Without it, the connection between your brain and
your muscles only transmit part of the information.
When Sana and Sawsen stand up with their eyes closed, their
muscles are working to keep them upright just like any other
person, but their muscle spindles aren’t informing their
brains on how to correct for balance, and they topple over.
When their eyes are open they can look to their
surroundings to glean that information instead.
For the able-bodied, it’s hard to comprehend
that the world might not be easily navigable.
Something as simple as finding your nose on your
face might not be as universal as we might think.
We can do things like installing ramps, and
automatic doors to help those with mobility issues,
but when it comes to invisible disabilities,
we just need to trust and help any way we can.
Science can tell us many things like how
to keep ourselves from getting sick, or
heal ailments we once thought impossible.
It can carry us across oceans, and over mountains.
What it cannot do, is show us how it feels
to be someone else, and to experience a world
that presents far more walls than doorways.
Chill: Hey everybody it’s me it’s Chill,
and I’m just here to say this one thing.
Subscribe to my main homie Brew
and you’ll be in for quite a treat!
And you know what, just an added bonus, like
this video, maybe even leave a comment, and
you just might make someone smile today.
Me.
I’ll be smiling.
Alright, with that said—Chill out!