"A very good question, and I'm glad you asked!" Washu beamed as though she had won the lottery- which she had once, thanks to the Washu Super-Odds Calculator- and gestured to the flashy piece of equipment with a wide grin. "Simply put, some people can't communicate the same way we can. Voice boxes destroyed, a stroke paralyzing them, whatever. But they can still think, and if they can think, then it's my job to make sure they can communicate! That's why I invented this little beauty."

She extended two probes from the main contraption, and put them to her own temples- having to brush through quite a bit of hair to do so- to show where it belonged. "The Transceiver can be connected to any computer, and it lets the person write or draw or whatever, just as they're thinking about it. Brilliant, isn't it? Revolutionizes medical therapy, doesn't it?"

She was stating all of that as though it was obvious, and equally obvious that the only proper response was 'Of course Doctor Washu, you are such a genius.'

...hey, it wasn't narcissism if it was the truth.