Paradoxically means in a seemingly impossible and at the same time opposite way.
Your are referring to the interview with OLIVER SACHS in which he talks about his cases/patients as a neurologist dealing with diseases like Alzheimers, Autism etc. and also the time he suffered from (I can't remember) I think it was a stroke that effected his left arm and hand?.
so it is saying that people who suffer these conditions will create words, sentences and absorb logic to us, to explain the world as they experience it. The interview and the subject matter is very specific, I would need to see that part of the interview and to know the patient and condition being discussed, to try and give a more detailed answer, if I can.