Oh yes, I have experienced this. I thought I was going crazy. They could not find anything wrong with my heart. That was good but frustrating. They are finding it is Migraines. I am on topomax. They are still increasing my medication. I am getting closer to where it seems be leveling off. I know what you are going through. They thought I was having TIA's for the longest of time. Please don't give up. I have several in one week as well. I have had most if not all the symptioms you have mentioned. I thought they were crazy when they started to change their focus from heart to brain but I am telling you anything is worth it when you are the one that feels like you just want to lay down and die just to make them go away.
My 39 yr sister recently passed away after having odd symptoms for years that they thought were neurological with no evidence of such with MRI's, CAT scans and other tests.
It turns out she had a hole in her heart and it allowed 2 blood clots go to her brain and kill her almost instantly.
Have her checked carefully by a cardiologist. I got checked and I have the same issue that now needs to be corrected with non-invasive surgery
Never stop searching and look for the non-obvious....
I had hate to hear this about your wife. Mine unfortunately, started with a few minutes then developed to hours and now, I have cognitive problems. With Hemi. Migraines with Ocular on the Right side... a person can have a mild stroke that does not show up, If I understand it correctly. They believe I have had a stroke during one of my attacks. If I can say recommendation. My partner traveled alot during my episodes so I did not have a daily person watching my changes til they became critical. Many hospital visits, etc. Make sure someone is with her on a regular basis to watch change in drup reactions, or pain length, etc.