My Yorkie Holly started having seizures at around 3 years of age, the vet said it was caused by her hormones when she was in season so he suggested that we had her spayed to stop it. She didnt convulse during her fits, she just went rigid and stared, totally unaware of her surroundings, usually lasting between 2 to 3 minutes. We had her spayed but the seizures still continued, not as regularly though, perhaps a couple of times a year, so I guess it wasnt her hormones, we never found out the real reason. She is 16 now and has a heart murmur and is going blind, my puppy is slowing down