I’d go with too fucked up to move. Remember, getting knocked out, even for a few seconds, is still a very serious concussion, and by extension a life threatening injury.
Off the top of my head, the symptoms should be: nausea, vertigo, (I think) blurred vision, and difficulty tracking (so, carrying on a conversation is also out).
This is actually what that “how many fingers am I holding up?” cliche is based on, it’s one way to judge if someone’s suffered a concussion, another is looking at pupil dilatation (by shining a light in their eye).
It’s also worth pointing out, because concussions are cumulative over time, these symptoms will actually get worse, and characters can’t learn to power through them. If your character’s getting clocked over the head repeatedly, they’ll end up dying from a blow to the head fairly quickly.
As a quick aside, there isn’t a safe way to render someone unconscious. I’ve been assuming a blow to the head, but tranquilizers require very specific doses (which vary based on weight and metabolism), and if you misjudge it even slightly, you can end up having no real effect, or outright killing the character you’re trying to tranq.
kickassfanfic said: You say ‘cumulative over time’ – is that indefinitely? Like if you haven’t been concussed in, say, two years, or TEN years, I dunno, and you get whonked upside the head again, is it just as bad as if your first whonk was the day before?
Not completely. Here’s the thing, when you suffer a concussion, what happens is your brain gets bounced off the inside of your skull. This results in bruising on the brain itself.
Someone who’s suffered a concussion is at substantially greater risk of suffering another, and any concussion they suffer will be more dangerous to them. This diminishes over time, but it never goes away fully. In other words, no, your brain never fully heals.
I’m sorry, I am oversimplifying things here. This is a really complex topic, and I’m not a doctor; but, from a writing standpoint? Yes. If your character is getting knocked unconscious, it will always be worse than the last time, regardless of if it was yesterday, or twenty years ago. If your character is getting clocked on the back of the head more than once or twice, they’re going to die.