I remember when I was a little kid "The Crazy Old Man" he was called. He swore up and down he could hear voices and music in his teeth.
It wasn't till after he died I read an article about how fillings in the teeth sometimes picked up radio frequencies.
That was when I resolved to never criticize or condemn someone who claimed something I could not believe or understand -- It might be just a case of some piece of information I didn't know yet.
I also resolved not to try to convince people of something they were determined not to believe.
So the basics have been available for around 50 years, maybe more. It is nice someone finally came up with a useful application for it. Perhaps miniaturization of circuitry accounts for the delay.