There's a picture of the electrode array on the Nature site, and it looks about 3cm x 3cm, with about 16 x 16 sensors. So 256 inputs to the analysis system. I

There's a picture of the electrode array on the Nature site, and it looks about 3cm x 3cm, with about 16 x 16 sensors. So 256 inputs to the analysis system. I know nothing about these kinds of electrodes, but how sensitive do they have to be? Sub-microvolt? And how fast? Sub-millisecond? Finally, on the results themselves. If I read it right, the sensors had been previously implanted into epilepsy patients, and were "re-purposed" for this study. So I assume they patients were able to speak? If so, it's trickier to demonstrate advantages for those who have lost the ability to speak.