Years ago, one of my mares had some seizures. It seemed to span about a year and we caught her at them 2-3 times. When we went out to feed, we found her kind of staggering and foaming at the mouth. I called the vet who arrived within about 45 minutes and each time, had we gone out at the time the vet arrived, we'd not have known she had an issue. Which made me think she'd been having them when we just were not around to notice. The final time the vet was out, she did some physical testing, like pulling her tongue out and she did not retract it quite as soon as she should (though she seemed "normal" to observe in the pen). She had me do different turns with her and her feet were not exactly coordinating as they should but within the span of her (short) visit, she was back to normal. She asked me to video if it ever happened again, but it never did. The last time was, I think, in fall 2005. She's a mare I drive and have a couple foals out of. One of my favorites. The first time I saw her having a seizure, I thought EPM or something worse, and honestly thought she was going to die (I am given to worst case projections), but it's been years and she's apparently perfectly fine.