Being serious for a second, and don't mean to sound blunt, but...
Given how frequently you do this/similar, Mr V6CDX, is it worth asking quack about your absent mindedness during your next checkup? Although, from even my own personal experience with you, this predates you little bump a couple of years back.
(suggested with the best intentions in mind)
No offence taken, and it's something that's been in hand for a long time.
I don't want to go into huge detail, but to answer the question, a consultant I saw last year in London has documented brain / neurological injuries, along with central nervous system damage, and a referral to a neurosurgeon, some distance away has already been made.
Not unreasonable given a head-on closing speed in excess of 130mph.
In particular, I am having problems with short term memory, personality, fatigue, and concentration (especially around learning new things).
It's one of those things whereas, as isolated incidents things seem like nothing, but there is a trend in that, they happen much more frequently - and it has been picked up by those close to me, moreso than myself.
The way the consultant described it to me, is that, although I don't recall specific parts of the impact, even in the unlikely event I didn't bash my head, the deceleration forces still causes the brain to impact the inside of the skull at those speeds.
Thanks for the kind suggestion, but it's already been picked up and is being investigated