Dr. Eddie Chang

I would say an area that even non-human primates have that can be specialized for vocalization.

It's a different form of communication than words, for example.

So there are a series of conditions.

They include things like brainstem stroke.

The brainstem is the part of the brain that connects the cerebrum, which is the top part, does our thinking and a lot of the motor control, speech, language, everything.

And the brainstem is what connects that to the spinal cord and the nerves that go out to the face and vocal tract.

So if you have a stroke there, you could be thinking all the wild, creative, intelligent thoughts you have in the mind and the cerebrum, but you can't get them out into words, or you can't get them out to your hand to write them down.

So that's a very severe form of paralysis called brainstem stroke.

There's another kind of conditions that we call neurodegenerative, where the nerve cells die, basically, or atrophy in a condition called

ALS.

That's a very severe form of paralysis.

In its extreme form, people essentially lose all voluntary movement.

The muscles to their diaphragm and their lungs essentially give out as well.

They get weakness there and then they can't breathe anymore.

In our field, these are kind of like the most devastating things that can happen.

This condition of what we call being locked in refers to this idea that you can have completely intact cognition and awareness, but have no way to express that.

no voluntary movement, no ability to speak.

And that is devastating because psychologically and socially, you know, you're completely isolated.

That's what we call locked-in syndrome.

And it's devastating.