Toddler Seizures?

If anyone has had similar symptoms with their toddlers, I'd love to hear about it. Our daughter started having strange episodes almost a year ago that are very rare, but suspicious when they happen. She puts her head down out of the blue, and her arms and body go limp. She hasn't fallen down, but almost does. Our neurologist hasn't been able to determine that they are definitely seizures, since they don't fit standard seizure descriptions. Three EEGs all showed mildly abnormal activity, but she didn't have any of those episodes during the EEGs. She had a normal MRI. These episodes are rare and have only happened once every few months or so. They were more frequent when she was younger for a while. She does seem to have some sensory issues, especially with sound, but she's not autistic. These sensory issues have been more pronounced lately, and the latest episode was last night. We were eating dinner, and she stood up, and her head went down and her eyes seemed to roll up (looking up). Her head doesn't seem to be limp but rather seized as tight to her neck as it can go. Her arms were limp and she started to fall forward when I caught her. It lasted for only 30 seconds or so, so I couldn't get it on video for our neurologist. I'm torn whether or not to put her on anti-seizure medicine, when no one has been able to determine if these are in fact seizures or not, and they happen so rarely. If anyone has had similar activity in their child that has been diagnosed, please let me know. Many thanks.