Retrograde amnesia

[Lithium]

Okay, so I was taking one of my services optional elections for CME this year, entitled 'Defensive Driver Course'. Essentially, just a reminder of safe driving principles/practices. Surprisingly, my services most frequent amount of accidents occur when backing up, but anyways.

Anyways, I'll get straight to my question. When you're assessing a head-injured patient post MVC, often, they all have some form of memory impairment before or after the accident. This is referred to as antegrade or retrograde amnesia. After taking the course however, I have some thoughts about retrograde amnesia.

In the course, we discussed 'highway hypnosis' and such. It's been proven that for people who do an aweful a lot of driving, especially of the same routes, that at times, they're subconcious can take over and drive for them, and that person is no longer consciously aware of their surroundings. I know it's happened to me for a few times, especially on my drive in or back from work, sometimes I won't be able to remember the events that's happened in the past few minutes.

So, suppose now this person is driving around 'subconciously' but they happen to be involved in an accident. With this new information (ie. hitting the steering wheel, loud crashing sounds) the brain snaps out of its state and brings the person back to reality and what's occuring. However, they have no recollection of the events that happened prior to the accident, simply because they were zoned out, not due to head injury.

What do you think? Is this plausible for most patients? I'm not trying to say that a person suffering from a head injury wouldn't show signs of this form of amnesia, only that, it may be more common for the reasons I listed above.

Discuss!

peace

[AZCEP]

Interesting thought.

Hard to say precisely how the brain will respond in each individual, but your thought process seems to make sense. Might be something to consider discussing with a neurologist/psychologist. Just be prepared for the "I don't know.", response.

[BEorP]

I believe I recently read somewhere about something related to this (not car accident specific). If I remember correctly, it said that when you zone out in a class but then are called on by the instructor, you can actually remember what has just been said (even though when it was said you were not consciously listening) so you can answer the question. I don't know if this is the kind of answer you were looking for... and I will try to find where I read that when I am awake.

[Asysin2leads]

I'd say that if you are really zoned out and then crash, you might not remember the specifics of your drive up until the point of the crash, but you'll definitely remember the specifics of the crash if you are not memory impaired. You may not be able to recite every song you listened to on the radio before you went off the road, but why you went off the road, whether you lost control or swerved to avoid Grandma McGurk, you'll definitely remember that. An analogy would be that if you were really engrossed in the latest best seller, you may not remember your clock chiming on the wall, but if someone comes up and punches you in the face, you'll remember who hit you. If someone can't remember the events prior to the crash, and they are not on alcohol or drugs, either they have a concussion or contusion, or they feel asleep while driving. In any event, the bottom line is that if someone is suffering memory deficits s/p an MVA, its time to go see Mr. CAT scan at Mr. Trauma Center, no matter what the intricacies of neuropsychology might be.

[Malignant-Hyperthermia]

Interesting...

I guess my only contribution is that it is fairly rare for person to fail only 1 point of the NEXUS criteria, most fail 2 or 3, so hi-way hypnosis would be unlikely to be the only indicator for head/spinal pecautions

Please dont ask me to find that, i have no idea where i read it but it stuck in my brain

[vivibonita]

Just be prepared for the "I don't know.", response.

or the "its all idiopathic" response ...

[iMac]

It would depend for each person. In the end I don't see that it matters. Chances are if they really didnt remember the events prior to the accident (due to an actual TBI) chances are you will have other obvious signs of head injury than just amnesia. I doubt you would get, it never happened to me anyways, a pt that can't remember what happened yet you have nothing else that could be obvious of a possible head injury (contusions, facial abrasions, changes in BP, pulse pressure, agitation etc) Then you would also potentially have other signs like damage to the inside of the vehicle, or cracked/broken helped etc...

Maybe its me, maybe a lot of you have seen that happen before, who knows. But from what I had experienced, I wouldnt get one without getting at least one more of the other.

[AnthonyM83]

it said that when you zone out in a class but then are called on by the instructor, you can actually remember what has just been said (even though when it was said you were not consciously listening) so you can answer the question. I

Dude this phenomena saved my ass more times than I can count! I've been trying to come up with a good term for it for awhile.

And I think Asysin's response is solid as far as remembering most the crash anyway. You might not remember up to the point of the crash, but you'll remember being shaken around or the noises and the car coming to rest.