Sorry to go over the same ground again, but I just wanted to clarify our conversation from a few days ago. Apologies if the following seems a little cold and technical.
You said that a blow to the head that produces mild or very mild concussion-like symptoms will very often not result in diffuse axonal injury, but may cause dendritic injury.
You also said that a short period of dizziness, confusion or a brief loss of consciousness immediately following head trauma would be classed as "mild or very mild" symptoms.
The question I wanted to ask is the following:
Are there always (or almost always, like 99% of the time) some noticeable symptoms very soon after a blow that is potentially injurious to the brain — even in the mildest cases? For example, if a concussion specialist had the misfortune of banging his or her head on a low-hanging doorway at a slow to normal walking speed (as I did) would their knowledge of concussions enable to rule out the possibility of dendritic injury within 10 minutes or so on the grounds that they hadn’t experienced any of the common immediate symptoms — e.g. brief loss of consciousness, seeing stars, ringing in the ears, feeling dizzy or confused, not being able to clearly remember the event? What I am saying is, are these immediate symptoms the minimum requirement to suspect any damage and would they be easily identifiable to someone who knew what they were looking for?
Also, if your answer to this question is that, yes, there can be some dendritic injury even without noticeable symptoms, is this type of dendritic injury (i.e. a near symptomless one) equivalent in severity to the type of injury caused by heading a soccer ball — i.e. so mild that you would have to do it hundreds or maybe thousands of times within a certain time-frame before there would be any impact on cognition?