Are Episodes Of Eye-rolling, Muscle Spasms, And Head Shaking In A Child With Down Syndrome Seizures Or Tics?

My daughter has trisomy 21. She’s 8 mo old. Recently she has started these episodes of eyes rolling back in head along with muscle spasms. She doesn’t know it happening when it’s happening but she has also started shaking her head back and forth. We have a neurology apt in. Dec to see if it’s seizures it until then it’s very concerning! How can I tell it if it’s some sort of tic.