Oliver Sacks has just published an article on ‘Hallucinations of musical notation’ in the neurology journal Brain that recounts eight cases of illusory sheet music escaping into the world.
The article makes the interesting point that the hallucinated musical notation is almost always nonsensical – either unreadable or not describing any listenable music – as described in this case study.
Arthur S., a surgeon and amateur pianist, was losing vision from macular degeneration. In 2007, he started ‘seeing’ musical notation for the first time. Its appearance was extremely realistic, the staves and clefs boldly printed on a white background ‘just like a sheet of real music’, and Dr. S. wondered for a moment whether some part of his brain was now generating his own original music. But when he looked more closely, he realized that the score was unreadable and unplayable. It was inordinately complicated, with four or six staves, impossibly complex chords with six or more notes on a single stem, and horizontal rows of multiple flats and sharps. It was, he said, ‘a potpourri of musical notation without any meaning’. He would see a page of this pseudo-music for a few seconds, and then it would suddenly disappear, replaced by another, equally nonsensical page. These hallucinations were sometimes intrusive and might cover a page he was trying to read or a letter he was trying to write.
Though Dr. S. has been unable to read real musical scores for some years, he wonders, as did Mrs. J., whether his lifelong immersion in music and musical scores might have determined the form of his hallucinations.
Sadly, the article is locked behind a paywall. However you can always request it via the #icanhazpdf hashtag on twitter .
Link to locked article on ‘Hallucinations of musical notation’.
Mind Hacks 
when I play solitaire on a binge for a few days, I see card arrangements in my mind, and often get caught up deciding the next moves. The cards aren’t fixed though and they rearrange themselves. I usually take that as a sign that I need a different diversion.
When I was writing my bachelor’s thesis, I would dream ceaselessly that I was staring at my books and taking notes, or writing senseless words on the computer screen. It’s no wonder that the things we immerse ourselves in drown our subconscious images as well.
Another great place to request articles is /r/scholar on reddit.
This also brings to mind the phenomenon of seeing writing/other symbolic matter in dreams. I have had many lucid/semi-lucid dreams where I was quite conscious of reading a page of writing (usually mine) and trying desperately “consciously” to make some sense of it, even just a fragment, that I could “bring over” with me when I awoke.
But it always slips through my grasp, and over time I have realized that there really isn’t anything there to begin with. It’s like the subconscious is just “painting” with symbols that it doesn’t understand, giving us the “gist” of a reading experience in all its sensory detail EXCEPT for the actual meaning.
(Not to suggest that I haven’t received creative inspiration from dreams; but these are almost always in the sensory or emotional realms.)
I’ve heard music in dreams that I later recognized on the radio. Maybe some kind of auditory deja vu because I doubt that I could have heard the music before in any situation except dreaming (E African funeral music). I even wrote about it in my diary before I heard it, alas not the score.