Check her dialogue. She definitely was.
“I saw records of other "patients," and what had been done to them. Some couldn't hear anything but static. Others, just... gibbering wrecks...Never going back... and Elijah was on his way here, so I couldn't stop to see if it was something I could fix......if you can even fix what happened to me when they jabbed the electrodes into my skull and turned my head into a flashlight."
This seems to indicate she was lobotomized.
Lengthy post coming up. Don't take offense at this, it's not aimed at you in particular, I'm just illustrating a point.
...
Despite pop-culture, lobotomy is a very specific neurosurgical procedure that, among other things, doesn't use electrodes. It is also largely abandoned as a procedure, given that the original reasons for its usage (various mental disorders) are treated differently nowadays (and given how well-developed Fallout world is in medical terms - think of stimpaks, autodocs, mentats etc - it is not far-fetched to assume that they have surpassed lobotomy too).
Ability of speech and comprehension of it are focused mostly in two areas of the brain, that is
Wernicke's area and
Broca's area. The first one is responsible for speech comprehension, while the second one is responsible for speech production.
To put it bluntly, first one understands what is being said, while the second one produces speech.
I am making it all very simple, of course. These are highly complex areas of our cortex, and they are interconnected with many, many other parts of our brain and sensory/motor systems.
With that all being said, I have little recollection of how Christina acts in the game, but from what I remember, she cannot speak
at all, while she understands human speech, and is quite adept at mimicry and using hand signs to elucidate a point. Given that she can understand speech and can non-verbally respond and after her vocal cords are restored she can immediately speak fluently, this implies that these two brain areas crucial for communication weren't damaged, or at least not that much.
@peadar87 has properly pointed out that Christine has a condition known as alexia (inability to read) which here goes hand-in-hand with agraphia (inability to write). These are acquired conditions that stem from cortical injury of a very specific brain area (we are not completely sure which one, but it seems to overlap parts of temporal, parietal and occipital lobe of the dominant hemisphere - areas in which Wernicke is too). In other words, Christina had this particular area of brain injured. Since it's such a small area, using an electrode to damage it is feasible (feasible in video game terms - electrodes can be placed directly to the cortex but AFAIK they are used to register impulses within the cortex, not to cause harm, but eh, I guess we can pretend it was done).
In any case, harming such a small area is a very "precise" injury.
Lobotomy is, for a lack of a better word, a brutal procedure that leaves massive, global effects both on patient's nervous system, as well as their psyche. Christina was unethically experimented on, sure, but no, she wasn't lobotomized.
It's worth noting that in Fallout world "lobotomy" is a somewhat loose term (think of Lobotomites), but as I've already pointed out, I think medicine in FO has moved past this procedure.
Also, if I am not wrong, Chris Avellone wrote Christina - he is known for meticulously researching the subjects and stuff about which he is writing, so I'm pretty sure he wouldn't resort to such a ubiquitous and incorrect term of pop-culture's understanding of lobotomy to explain development of an important character. I'm not saying he read dozens of neurology and neurosurgery textbooks either, but you catch my drift.
P.S. I should point out that while I have a solid basis in neurology, I am not a neurologist. I'm a dude on a Fallout forum that's sleepy as fuck. Take stuff with grain of salt.
That being said, I'm confident in what I've written here.