Possible narcolepsy, epilepsy in my new horse?

["guest@endurance.net" <guest@endurance.net>]

DebbieLewis dlewis@condorearth.com
The horse is a 9-year old Egyptian Arab gelding, two weeks into a 30-day trial period.  Symptoms have been observed twice while loading into a trailer, and possibly once in a show ring.  (i.e. "stressful" situations)  The horse "zones out", drops his head, eyes glaze over, lips vibrate (almost electrically)(not a quiver or a flopping), his knees go unsteady (but do not buckle) and he is non-responsive to voice commands.  Gentle tugs on the halter have no effect.  A slow, firm pull on the halter will bring up his head, but it drops again.  Duration of sypmtoms is about one-half minute to two minutes.  Then he pops back, lifts his head, shakes it, and returns to the task at hand.  One time he had a small piece of carrot in his mouth, and stopped chewing.  When he came to, he began chewing again and finished the carrot.  No signs of distress or sweating.  No sign of choke, convulsions, twitching, or involuntary body movement.  It looks like he is falling asleep.  My daughter said he may have done the same thing while lined up in the show ring.  She thought he might fall.  I haven't observed this at any other time.  The previous owner said she only saw this "behavior" once, on a trail ride long ago, and assumed it was no problem.

Has anyone seen anything similar?  This horse had a negative coggins test, passed a prepurchase exam and showed no temperature, respiratory or other abnormalities.  He does have an extremely calm, placid personality, and a slow, smooth way of going.  Could this be epilepsy?  narcolepsy?  EPM?  encephalitis?  brain electrical imbalance? rabies?  stress from thye move?  Is it contagious?  Should I separate him from the herd?  He was an only child, and lived along before I got him.  Hadn't left home for several months.  

My vet is now recommending that I not buy, and has revised his opinions regarding the prepurchase exam.  This horse has not passed.  I like this little guy's quiet demeanor, and would like to keep him.  Thank you for any advice or ideas that you may have.  I hope I haven't been too wordy or too brief.