it's cumbersome. >> lynn mackler: it is. >> pelley: but recently, scott found a new voice. >> scott macklere p.c.? i apologize for the quality of the voice. >> pelley: scott wrote these words, one letter at a time, with nothing but his thoughts and the help of what's called a brain-computer interface or b.c.i. he wears a cap that picks up the electrical activity of his brain and allows him to select letters simply by thinking about them. then, the computer turns his sentences into speech. >> scott mackler: i hate being helpless and when other people put words in my mouth. pelley: well, this is a very unusual interview for "60 minutes." we've done something that we never, ever do, and that is we've submitted the questions in advance, because it takes scott a little while to put the answers together using the b.c.i. device. scott, i understand that, earlier in the progression of this disease, you said that, at the point you had to go on a ventilator, you didn't want to go on anymore. but today, you are on a ventilator, and i'm curious about what changed your mind. >> scott mackler: because i