I have dyslexia, no problems with captchas though. In fact I found the examples from OP article to be not all that difficult. Maybe it's because when I am solving the capture, I just look at one letter at a time, instead of trying to read and comprehend the word. I found it that in many cases the control word isn't actually a word at all, just string of characters. I usually have 80-90% success rate nowadays, used to be 100%, but they are really getting more and more difficult.