Q and A: What Injuries Might Cause My Character’s Amnesia and How Would It Be Evaluated and Treated?

11 Apr

Q: I want my victim and her best friend to be in a car accident. One girl dies instantly, and it looks like the second girl will die too, but she survives. I need her to be in a coma then wake up and have temporary amnesia but then after several days (specifically around 10) she completely regains her memory of the events immediately before the accident, so that she can tell the police that the driver (the deceased) was trying to use her brakes, instead of simply running a red light. Is this realistic? Could the exact cause of the coma (blood clot, structural damage, etc) be diagnosed and if so how? What kind of head injury would cause these injuries? What treatments if any could be used to bring her out of the coma and amnesia? What about any long-term neurological effects?

A: The short answer is that all of this will work for your story. Comas and amnesia are funny things and virtually anything can happen.

A comatose person may remain so for days or months or years and then wake up gradually, in fits and spurts, or suddenly. The victim would likely be somewhat confused and disoriented for a period of time—this could be minutes, hours, days, or weeks—and might then return completely to normal or might be left with all sorts of mental deficits such as confusion and disorientation, and could have personality changes. They could be withdrawn, very talkative and outgoing, paranoid, angry and combative, quiet and passive, or any thing else. Or not. They could wake up and be normal is every respects. All is possible.

She would have no memory for the time she was comatose and may or may not remember what came before. This is called retrograde amnesia. Her loss of memory could go back any period of time before the accident—a few minutes, a few hours, days, months, years, or forever And her memory of previous events may be partial, spotty, or complete. It may return slowly over days, weeks, or months or may return quickly. Again, all is possible.

The bottom line is that coma and amnesia are both poorly understood and come in thousands of flavors. This is good for you since you can craft your story any way you wish and it will work.

When she came to the hospital she would go through a battery of tests designed to find out if she had any serious brain injury. These could include skull X-rays, CT scans, MRIs, EEGs (Electroencephalogram–a measure of brain wave activity), spinal taps, and other things. When the tests all came back normal, the diagnosis would be a cerebral contusion (basically a brain bruise). She would be given steroids (like Decadron 8 milligrams IV twice a day) to lessen any brain swelling. Other than that, time is the only treatment.

Once the victim woke up the MD would perform a complete neurological exam to assess brain function. This is complex and I doubt you really need it for your story anyway. He would then perform a mental status exam, which is designed to assess orientation, memory, and cognitive function. He does this with a series of questions. The victim may be able to answer them all, only some of them, or none of them depending upon her mental status. This is a huge subject but a few things he might do would be:

Orientation means does the person know who he and others are, the date, his location, and what situation he is in. The MD might ask: What’s your name? How old are you? Point to the victim’s sister, friend, etc. and ask Who is this? What is today’s date? Who is the president? What type of building are we in?

Memory would be tested by asking: What do you last remember? He might then tell her the name of everyone in the room and ask her to repeat them. Or say a sequence of numbers and get her the repeat them back.

Cognitive function means the ability to understand concepts and connections. He might ask her to subtract 7 from 100 and 7 from that number and so on. Answer: 100, 93, 86, 79, etc. He might ask her what does the phrase cry over spilt milk mean? Or a penny saved is a penny earned. Such questions test her ability to reason and use abstract thinking.

It’s more complex than this but this should help.

Your victim might not require anything and could go home a week after awakening—depending upon what other injuries she sustained of course. More likely she would need psychiatric counseling and physical therapy (PT). Again, you have great leeway here.


Posted by on April 11, 2012 in Medical Issues, Q&A, Trauma


8 responses to “Q and A: What Injuries Might Cause My Character’s Amnesia and How Would It Be Evaluated and Treated?

  1. Nancy DeMarco

    April 11, 2012 at 7:30 pm

    Great information – thank you. I wondered – I had a horse with a C2 fracture (vertebral body) and a cord injury, and along with dexamethasone, she was given DMSO IV. She stabilized within a couple hours, and eventually had a complete recovery. Is IV DMSO ever used in people for CNS injuries? Just curious – it could have been the dex, but this mare’s response to the combination was amazing.


  2. kaye george

    April 11, 2012 at 10:00 pm

    So, no tests would be done while the patient was still unconscious? Wouldn’t they check for bleeding in the brain with an MRI and/or CT scan?


    • D.P. Lyle, MD

      April 12, 2012 at 7:34 am

      Of course. A complete neuro work up including a CT or MRI would be done to rule out any significant brain injury. If all was normal it might be considered to be a simple concussion. This was covered in my answer.


      • Margaret Koch

        April 12, 2012 at 8:16 am

        D.P. Lyle asked on the DL list what type of injury might cause his character’s amnesia: (I wrote this before I knew that it had to be a car accident, and I didn’t know D.P. was an M.D. this might not be news to him.)

        I think you have a lot of options. Any head injury that would cause shearing of neuronal tails — that includes most impact injuries and even whiplash — could cause amnesia. The problem comes when you address duration of amnesia. Brief is easy. Extended is harder to make credible unless you also have injuries extensive enough that would interfere with other areas of function.
        You can’t easily do it with an internal vascular event like a stroke, because memory is scattered through the brain, not just in one place.
        I’d prefer to make it psychological, or the result of a near-death drug experience — that would involve the whole brain. Electrical shock would do it, too. You’d have more freedom with psychological, because the causes are so individual, and amnesias without any identifiable physical cause have lasted for years.

        (I added this to my DL response to make it specific to the car accident. I suggest that you go with brief amnesia (a couple of days) due to traumatic brain injury, but then describe fragmented memory coming back with strong psychological components (grief, survivor guilt) that complicate the full return of memory. Since the memory of another driver being at fault is crucial, whose fault it was would have strong emotional repercussions, and the desire to blame oneself could interfere so that you could extend it out to the ten days you need, or more.)

        Margaret Koch
        The Dr. Stark Mystery Series
        CAULDRON, Book Seven, to be available by Hallowe’en


  3. murderinessex

    April 12, 2012 at 9:01 am

    From a writing point of view I would evaluate it as a cheap trick and treat it by replacing it with a less hackneyed plot device.



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