Do you think this is related to her neurological problems?
I don't think so, however that did cross my mind. She was being really full of it (the "Crazy Ay-rab" switch had been flipped, LOL!), the ground was the littlest bit slick, and I think she just took a spill because she forgot to really think her actions through. I worded it a little bit dramatically in my first post. What happened was she came down from this air maneuver, her right hind leg slipped on the little bank thing she came down on and went under her-tripping her left hind, her back end then went down while her front end scrambled to keep her up, then she slid over her right front leg with her left front still out, scraped up the right leg, stopped sliding, and got to her feet very gingerly and carefully. She obviously knew where all her legs were and she was really calm about it (I would figure that a horse that had suffered a neurological thing would be less calm in a situation where their legs went out from under them, but I could be wrong). She didn't thrash around, she just let the fall stop itself once she realized that she couldn't fix it. But yeah, I think it was just a case of the older mare forgetting her age and trying to be silly.
The vet who checked her out (one of the best in the area, no one I've talked to about her has any complaints and she has her own column in the local newspaper) a few weeks ago said that there was a slight possibility of something neurological like Wobbler's from a spinal tumor going on (among a whole host of simpler things that could have similar manifestations) but that it wasn't anything to worry about unless it started being more apparent since there are so many other things it could be.
I have since decided that I'm not going to worry about all the things it could be and just enjoy her. The most likely cause is that she's just aging. She is 26 and though she's been acting 5 for the last 3 years, her age has to catch up to her one day. She's a very smart mare and she lets me know whenever something isn't "right" so I have no doubts that if she felt at all like her body wasn't ok, she'd do everything possible to let me know. Since she's acting like her body is ok, I'm going to trust her on that one and not worry too much, like my nature wants me to, about the mild possibility of neurological issues.
Also, I gave her a little bute with her dinner (.5 grams) just to take the edge off because she was walking a little gingerly during her lesson earlier. Thankfully the later lesson cancelled. She'll have all day tomorrow off except for maybe a walk in-hand on a trail just to get her moving.