You guys need to read
The Brain that Changes Itself, by Norman Doidge, M.D.
There is a section where he describes an interesting therapy effect, and a theory to explain it. When people practice speaking, such as memorizing speeches, their handwriting improves. If someone does lots of handwriting, especially nice italic cursive, not just scribbling, their speech will improve as well.
The theory is that some section of the brain is dedicated to the task of sequencing rapid motor movements, ones where there is not enough time to do all the adjustments on the fly. Both handwriting and speaking are examples that require bursts of very rapid and precise movements, all under the control of nerves firing, of course.
My notion is that since the AN can mess with our speech to some degree, it forces the "rapid movement sequencer" to go through some adaptations as well, thus messing with our handwriting at the same time. I like this better than the idea that I use a computer too much or that I'm just getting older, although both of those are true too.
Eve, though it is a motor issue, it is at least a high order motor issue, and I think we can interpret Cognitive for the purposes of this board as meaning "brain thingy", rather than a more precise definition.
Steve