Thanks for everyone's input. I know I mentioned one study in particular, and Mark is right to point out the nuances of it. There are many others, including textbooks, which mention that benzos cause further cognitive damage, but it is true that no study has yet ascertained exactly the amount of damage and whether or not it ever goes away in the long term.

It may be that my healing is simply slow/has stopped, just wanted to warn against potential dangers and see if anyone else had some insight. For those who come across this later, feel free to chime in. Seems like our collective experience -- as incomplete as it is -- may be the closest we will get to knowing the effect of these drugs on brain injury.