Some examples:
How many times I could raise and lower my leg before being exhausted.
Number of steps I could take at a time.
Words I blocked on.
Number of times I became altogether unable to complete a sentence. (Though this was more approximate.)
Number of pushups I could do.
Distance I could walk.
Complexity of the hardest logic-puzzle I'd successfully solved.
How many words I could write before my hand was exhausted.
How coherently I could write (I still have somewhere a piece of paper on which I wrote the same sentence, over and over, on each line; it gradually morphs from a literally indecipherable scrawl to something indistinguishable from a normal-though-sloppy person's handwriting.)

These were, of course, at different times in my recovery.