Evaluating cerebral concussion.

Years ago we developed a rat model that was consistently comatose for 1-2 seconds following 50 G acceleration of the head. Motor normalcy returned in about 10 seconds, and normal memory in an hour. There were immediate electroencephalogram and transmitter changes. All these returned to normal within an hour following 1 or 20 such concussions. We could find no light or electron microscopic changes. Halothane anesthesia precludes measurement of coma and introduces distortion of metabolite findings. To date our findings indicated concussion at this level is completely reversible.