Thanks for using the forum. I am happy to address your questions, and my answer will be based on the information you provided here. Please make sure you recognize that this forum is for educational purposes only, and it does not substitute for a formal office visit with a doctor.
Without the ability to examine and obtain a history, I cannot tell you what the exact cause of the symptoms is. However I will try to provide you with some useful information.
I am sorry to hear that your wife has had a stroke. I hope she recovers well with rehab. Certainly we can see seizures happen after a stroke because the area injuired in the brain can initiate electrical storms which manifest as convulsions. I think she received an appropriate evaluation with extended EEG monitoring.
The advantage of the EEG is that it can read the electricity patterns being generated by the brain, so when a patient has any activity which looks like a seizure, the EEG can tell us whether the patient was having a n electrical distubance in the brain which could account for the motor activity/convulsive activity seen.
If no electrical disturbance is seen on the EEG during the period when a seizure activity is happening, then there are two possibilities. One is that the electrical disturbance is too mild to be picked up by the EEG scalp electrodes (this possibility is unlikely if the patient is having a grand mal like seizure activity). The other possibility like you related is “non epileptic seizures” or non epileptic events.
Non epileptic events are not uncommon. One cause of it like it was explained to you is possible masked depression/anxiety/stress. It is important to realize that production of the motor/convulsive activity in a nonepileptic event is not intentional. The brain acts through pathways to convert masked stress/anxiety/depression into motor/convulsive activity.
Just the stress from having a stroke or the other event you have mentioned may be enough to precipitate a non epileptic event in anyone
Thank you for this opportunity to answer your questions, I hope you find the information I have provided useful, good luck.