So I wouldn't say brain damage leaving you alive but afflicted is as "extremely rare" as you make it out to be.
Ya, there's just one little descriptive chunk that will clear it up: brain damage from fighting(or work accidents) should be mostly lethal.
I think that before we accept the blanket statement that brain damage should be mostly lethal, we should have an expert chime in. The brain's very modular, and location of trauma has a huge effect on what happens. I mean . . . brain stem gets damaged, you're probably toast. Hypothalamus gets damaged, probably toast. Anything having to do with maintaining homeostasis, and your outlook's not too rosy. Obviously, any attack that immediately immediately pulverizes everything in your skull will encompass these areas which are vital to minute-by-minute function.
I'm reasonably sure, though, that anything causing damage in other ways--glancing blows by blunt objects, concussions, slashing injuries by smaller weapons, and especially piercing attacks--maybe things like spears assuming the area affected is limited, but especially bolts and arrows--is going to cause a variety of behavioral issues.
I'd imagine seizures would be one of the most common manifestations, on par with blindness and loss of other senses or motor dysfunctions. Probably more likely than, "Hey! I like Olivine!", anyway.
edit: and by "an expert," I don't mean me.
Well we can gather quite a bit of information from the old Phineas Gage story.
*1850ish he had an (artifact) iron rod shot through his head in a relatively vertical angle. Psychology classes mention him a lot to explain how we figured out what the frontal lobe does based on how his apparently ceased it's functions, being severed and all. They don't usually give details about how bits of brain fell out of his head later while he was vomiting but hey, they teach this stuff to little kids.
Realistically I expect he'd have bled out in earlier eras and even so he got some kind of nasty infection that probably had a big chance of killing him.
In particular though I'd like to know any details about what the rod did to th bones it went through. I don't know the anatomy of the skull well enough to tell how much bone it went through at the bottom and can't begin to make predictions about how much damage bits of bone would have caused but I can see the top of the skull having not done much damage if there was no way to reverse the direction of force.
I don't know, I think it would be pretty depressing to see my newly recovered brain damage victim stop what they were doing and start seizuring all over the place.
Agreed. There's an adage that usually gets tossed around which hasn't yet -- it's important that additional features add fun or gameplay depth.
This doesn't add depth, because the very crux of it is that "we can't do anything about brain injuries." If they act like other injuries and just make the dwarf bedridden? That's cool, that's how I understand this concept should work. If they make the dwarf start doing something else, like forgetting jobs or who she's married to? I can't do anything about that. Why isn't the dwarf just bedridden?
Whether it adds "fun" is more contestable, but I don't think there are enough "personality matters" decisions in the game (nor a high enough resolution to observe them) that this is a fair argument right now. What kind of 'quirks' do you envision? If Toady were to go out of his way and add entirely new actions, then I could understand this working out -- battered dwarves who constantly took breaks to commiserate with the fortress's war dogs, or something like that. But I think that this would still more be "zany for the sake of zany" than "personality matters," no matter how it was implemented at present. Probably best to wait for the arc where socialization will be tackled.
EDIT: Trepanation would be a legitimate way to tackle the most commonly fatal brain injuries for adults. It's not out of the question to implement!
I'm thinking if they're doing the rarer brain-altering-injury stuff it would mostly just be pissing off friends until they lowered in status and possibly making new friends. In a more dark-age sort of society taking breaks to talk to dogs probably gets you locked up and that's manageable enough.
So, thanks to today's update, it seems like gremlins will be Fun incarnate. Pulling ftw levers, letting megabeasts loose, and sneaking up from underground? I think fire imps may have a challenger for "creature that has most often screwed over my fort".
I've been setting up a nice control room with all my levers and the note system to say which is which anyway so unless I get tons of stuff set up but forget to guard it I won't have quite so much FUN.
I'm thinking about enabling mechanics on just about everyone and just doing workshop profiles so I can get mechanisms installed quickly (seems like even with three or four mechanics they always want to eat and haul rocks around for half a season before work starts on that lever,) and thus have some stuff off by what it actually does.
If there's any ability to tell when you need to be extra careful you could have a control room with floodgates instead of doors and have the lever for the floodgate walled off.
but we like convenience even if it's risky so I'm sure Gremlins will be plenty of FUN for practically everyone n_n
The lack of chasms or pits is going to make disposal a little tricky. Hopefully we can still atom-smash.
Did that included glowing pit tiles?