Anybody use fitbit or similar to track sleep?

Since my son's last seizure during his sleep, we purchased basis(like fitbit) to monitor or better understand his sleep pattern. My son is 7 but also has CP. Although he is verbal and can communicate with us, he does not know or tell when he has seizures. Since we got his sleep monitor, we are seeing heartrate spikes during his sleep in 150-160 range lasting anywhere from 5 min to 1 and 1/2 hours. I have read that heartrate increase can happen during nightmare or night terror and we know it is not necessarily seizure. That said, I don't think it is normal to have those high spikes 3-4 times a week. Does anyone use those and see any pattern like his? Do you know those are when you have nightmare? Maybe seizure? I ask my son everytime I see those spikes if he had bad dreams or if he woke up during the night(as sometimes it shows he was awake/walking etc. during the night), he says no every time but I don't know how credible his answers are. His neuro is concerned enough to order him video EEG but next available is not till April... Any thoughts or input would be appreciated! Thank you!