Thank you, Mark. It is possible indeed, although I doubt it is what happened: I remember quite clearly what I did just before sleeping, and I was fine. Another possibility is that I got up during the night, bumped my head, went back to bed, and do not remember this at all.

I might be overreacting but I am not as confident as you are that movements while asleep are necessarily slow. In the past I have seen several times my ex-girlfriend, who was prone to having nightmares, bolting up, and screaming "no", as if she were trying to avoid a danger. And my retrospective impression is that this movement was quite abrupt.

I have a couple of questions for you and others, if I may. I am now at day 10 after this impact and doing my best to recover from it (I am off work for now). So,

• Is it ok to use screens (with moderation) as soon as the sensitivity disappears, or should I avoid them for several weeks? I have seen conflicting advice on that.
  
• When is it safe to see the chiropractor again for my neck? This was very efficient to treat my tension headaches before this impact, but I am afraid to see her too soon after this new concussion, as her manipulations make my head move a bit.
  
• Are jigsaw puzzles and audio books ok during the active phase of the recovery? I am trying to keep myself busy...

Thank you again, and my best wishes.