About 8 year ago, I had a TIA while in hospital for kidney stones. I had full hemiplegia paralysis on the left side, with facial droop, and difficulty speaking. A couple years later, I began having sudden spells of not being able to speak that lasted about 45 minutes. I could not form words with my mouth, could not whisper, but could write fine. As "whatever" it was "wore off" or recovered, I'd begin to be able to pronounce "ah", "oh", but not "oo". Over another 10 minutes, I may be able to say "Ma", "Pa", "Ta" etc, and I recovered to full function like this. This happened many times. After so many, as I recovered, I would be able to force my speech but it sounded distorted, like I'd lost muscle tone in my tongue and lips. Almost like a muscular dystrophy, but always immediate onset, and lasting about 45 minutes.
I have also had these rather brief episodes of what I perceived as "falling asleep", but I was aware of what was going on around me. If I was talking to someone, I would continue talking, but my words became "sleep talk", which were completely nonsensical, but I didn't know it. After some amount of time, maybe 5 minutes, I would "snap out" of it, and realize that I was just speaking nonsense, and excused myself with "never mind" when the people I was talking to behaved confused. I realized what happened, did not notice the onset, or what to do with that, and I recovered, recalling the event. It appeared almost as a "micro-sleep". What kinds of neurological condition might cause these things? Could the be "vasoconstrictive" events?