My dad is 52 and in great health. Last year he had "spells" where he would go from being 'normal' to incoherent, disconnected speech (not making sense), being slightly off-balance, and later could not remember that point in time nor some events prior to it. A "spell" would last anywhere from 30 minutes to 12+ hours.
After much prodding, he went to a doctor. His general health is fantastic (blood pressure lower than mine!). They ran some scans on his brain and found nothing.
It had been a long time since he experienced one of these "spells" until few days ago. This one was slightly different than before, however. He was at a pizza place having dinner, and began "nodding off" to sleep. His girlfriend and my son kept trying to shake him awake, but he kept nodding. They finally got him home, and he wanted to go to bed - and he slept for 12 hours. When he woke up, he could not remember the entire previous day.
Should I be concerned that TIA's could be happening, even despite his good BP and cholesterol levels? Could something else be causing these kinds of events?