I suffer from short term memory loss. It runs in my family... At least I think it does... Where are they?

-- Finding Nemo

The drama of rekindling relationships in the setting of amnesia, the classic pistol whip to induce unconsciousness, memory loss as a way to cover plot holes... head injuries and amnesia pervade narratives. From soap operas to Momento, memory loss has a special way of creating tension in a story.

But what myths has the media spun for head trauma and memory loss? Let's start with the inciting injuries and then the aftermaths to get a better idea of how the medical world sees traumatic brain injury and its sequela.

Head Trauma

Picture it. Our heroine struggles in the clutches of the devilishly handsome--and for some reason shirtless--mafia boss. In her feisty disobedience, he pulls his gun to threaten her. True to her willful spirit, she spits in his eye. In an annoyed effort to subdue her, he whips her with butt of his gun and she collapses into an artistic heap. Hours later, she awakens from this assault, furious and thirsty for vengeance. No headache and hardly a hair out of place.

Despite the temptation of temporarily incapacitating a character with some well-placed head trauma, the real thing isn't quite so easy.

Let's revisit. Only this time, mafia boss is at a bar with his brother. One drink leads to another and--toxic masculinity being high at a place like this one--a bar fight breaks out. In the scuffle, his brother is hit in the side of the head and falls to the ground, unresponsive. Handsome mafia man rushes to his side. Fortunately, he aced his mandatory mafia first aid course and knows to check the airway, breathing, and circulation of his loyal and injured brother. Brother doesn't respond to verbal or painful stimuli so the boss rushes him to the hospital.

Once in the resuscitation bay, the doctors take over. If they're worried about the patient's ability to protect their own airway, they'll intubate to prevent adding vomit-induced airway occlusion to the head trauma. Provided that the patient stays stable enough to make it there, they'll rush him to the CT scanner to check for intracranial injuries.

They wait in the dark reading room, peering over the shoulder of the technician as the scan is sent to the computer screen. Bright white lights up on the screen. An epidural hematoma -- a broken artery has bled into the space between the skull and the covering layer of the brain and the increased pressure is a life threat.

The patient is rushed to the Operating Room, neurosurgery on the way to perform a craniotomy to evacuate the bleed or the ballsy rural Emergency Doctor drills burr holes in his skull to relieve the pressure before the patient can be transported to a higher level of care.

The recovery is tough: it's a long road that includes physical, occupational, and speech therapy. It's for this reason in the future, when he's dealing with the deliciously spirited heroine, our handsome mafia boss knows not to give her irreparable brain damage.

Wait. So every head injury causes brain bleeding?

Exaggeration on my part -- but even small head injuries can have cumulative effects.

Epidural hematomas (an arterial bleed between the skull and the layers covering the brain) are medical emergencies. The middle meningeal artery, the usual culprit for these bad boys, very quickly creates a large space-occupying hematoma (big collection of blood) that threatens to push the squishy brain out of the bottom of the skull. Which is bad. It's called herniation and it's not compatible with life. These patients rapidly need an intervention to release that pressure--either in the form of decompressive craniotomy or Burr hole. Classically, these patients will get hit in the head and have a "lucid interval" before rapidly progressing into unresponsiveness. However, this classic textbook picture doesn't always live up to real life (or to our example above).

Usually due to a tear in veins, subdural hematomas theoretically move slower. This intracranial brain occurs between the layers that cover the brain, specifically, between the epidural and subdural layers. Patients who have this type of bleed will classically have a progression of symptoms, steadily declining until they become unresponsive. Due to the pressure of an expanding bleed, these patients will also need decompression in a large enough bleed or close observation in a stable one.

While other brain bleeds can occur in trauma, these two represent the dramatic, intervention-required emergencies. But even with prompt intervention, the recoveries aren't easy. Speech therapists will be consulted to assess that the patient can safely swallow. Occupational and physical therapy might be needed to help retraining motor skills.

What about comas? Do people wake up from those?

Comas cover a huge range of pathology. To stick with the noggin-theme, I'll mention Diffuse Axonal Injury. This happens during trauma when the forces of the event (hypothetically) cause a shearing force within the brain, injurying the long tails of the brain cells.

Waking up from a coma isn't as easy as a prince sucking a piece of apple out of one's mouth. Or maybe I'm just practicing medicine incorrectly (1).

Ok. So what about amnesia?

There are two main types of amnesia (2): retrograde amnesia and anterograde amnesia.

Retrograde amnesia is the inability to remember memories that occurred before a certain point. This usually means the accident leading up to the injury, but can track as far back as a narrative might need. In the narratives of Anastasia (let's be real, the Dreamworks one is our favorite), she suffers from retrograde amnesia.

Anterograde amnesia is the inability to record memories after a certain point. Again, namely directly after the injury. The psychological thriller Momento is famous for utilizing this type of amnesia to create tension. Dory, from Finding Nemo, also suffers from anterograde amnesia.

I think romance dramas also like to utilize global amnesia. That is, the person forgets everything except their fundamental skills (namely things like how to breathe and walk and look glamorous in a hospital gown).

But what if it's just a "small" head injury? I really need my MC to be knocked out!!

As the evidence piles up, it seems like there is no such thing as a "small" head injury. To look into how physicians risk stratify head injuries, a loss of consciousness is a big deal. If patient's state they can't remember the seconds before/after an injury, it triggers our brains to look for these scary brain injuries.

Some Emergency doctors are more conservative than others, but if a patient told me they'd been knocked unconscious for 3 hours and then fought off their sexy kidnapper/assailant, I'd probably admit them for observation (even with a negative CT). And they'd definitely need a social work consult.

So I can't knock my MC out?

If you don't want to hear my nitpicking, do it a different way: bag over the head, magic, blow darts, a secret new drug (3)...just don't inadvertently give your characters irreparable brain damage for the sake of moving your narrative from point A to point B.

Because even injuries without loss of consciousness can cause pathology. As we look at athletes who unfortunately develop long term pathology from cumulative concussions and head injuries, we're beginning to see that even "small" head injuries have big effects. Chronic traumatic encephalopathy is thought to be caused by repetitive head trauma.

The brain is important.

If you're going to have pistol whipping mafia bosses, make sure your protagonist is wearing a plot-helmet.

And learned how to collapse in a graceful heap.

Footnotes

(1) If you're a prince in need of a job, I might be able to find work for you.

(2) There is a huge list of different types of amnesias, but for the sake of brevity (and an unforgiving schedule), we'll stick to the famous ones.

(3) We all know that chloroform is another unrealistic method to subdue someone