Oliver Sacks' books are usually crammed with amazing stories. So much so that even the footnotes should never be skipped.
I just started "The Mind's Eye" and found this tantalizing story relegated to a footnote:
"2. I was reminded, when Lilian told me this, of a patient I had seen in the hospital some years before, who had overnight become totally paralyzed from a spinal cord infection, a fulminating myelitis. When it became evident that no recovery was forthcoming, she fell into despair, felt that her life was over - not only the great things of life but the little familiar pleasures of each day, like doing the New York Times crossword, to which she was addicted. She requested that the Times be brought to her each day, so that at least she could look at the puzzle, get its configuration, run her eyes along the clues. But when she did this something extraordinary happened, for as she looked at the clues, the answers seemed to write themselves in their spaces. Her visual imagery strengthened over the next few weeks, until she found she was able to hold the entire crossword and its clues in her mind after a single, intense inspection, and then solve it, mentally, at her leisure later in the day. This became a source of great solace to her, in her paralysis; she had no idea, she later told me, that such powers of memory and imagery were available to her."
The Mind's Eye
footnote, p. 24
"Such powers of memory and imagery" are probably latent in all brains but lie dormant until they're forced into service by the necessity of extreme deprivation in other areas. In other words, it's a skill everyone would like to have but certainly not at the apparent cost.
His book, "Awakenings" also has tales of powers of visualization developed by the post-encephalitic patients he was treating. They were not spine damaged but frequently "frozen" by the Parkinson's-like aftermath of their encephalitis. Several of them seemed to have developed the ability to occasionally escape their plight by entry into full-blown hallucinatory worlds of their own creation.
"The Mind's Eye" came out in 2010. His most recent book, "Hallucinations" may go into more detail about the circumstances under which such things happen. I'm eager to read it.