In A Nutshell
It’s a plot point in almost every movie and television show that features a story about amnesia. The memory loss includes forgetting your name, who you are, and all of your close family members . . . right? Actually, most types of amnesia leave all this knowledge intact and are characterized by an inability to form new memories or recall old but recent ones.
The Whole Bushel
We’ve all seen the movies and television shows where a character suffers from amnesia for one reason or another. Suddenly, they can’t remember what their name is, what they do, who they are, where they live, or who their family members are. While it’s a brilliant (if not overused) plot device, amnesia usually doesn’t work that way.
There are two main types of amnesia. Anterograde amnesia means that the person can no longer form new memories. Anything that happens after the event, accident, or illness that triggered the amnesia is forgotten right after it happens.
Retrograde amnesia is the type of amnesia we’re probably more familiar with. This is the type that impacts past memories, leaving the brain able to form new ones but unable to recall old ones. Where most fiction gets it wrong, though, is in what memories this impacts.
Most people who suffer from retrograde amnesia have their short-term memory impacted. Much more likely to survive are long-term memories that have been carried with you for years and are well ingrained into not just your brain, but your identity and your personality. That includes your name and who you are. Many people suffering from amnesia will remember details from their childhood, but not remember what they did for dinner the night before.
In some cases, there are some other, less commonly known symptoms of amnesia. A person might remember events, but have them placed at the wrong time. They might think that a birthday party from their childhood happened yesterday, or remember conversations from years ago as happening last week. Confusion and disorientation—often coupled with these misplaced memories—is common.
A person might also remember things that never happened to them as the brain makes up its own memories to replace the ones that are missing.
Another thing that’s often misrepresented is the idea that a person can slowly recover their memories and be aware that it’s happening. Often, a person with amnesia isn’t aware of the missing memories, and when they do return, they have no recollection of having gone through an episode of amnesia.
It’s also important to note that the memory loss that’s associated with amnesia is completely different from the memory loss that’s associated with dementia. With dementia, there are a myriad of symptoms that just aren’t found with amnesia, which impacts only the memory.
The main causes of amnesia are another area where fiction largely gets it wrong. We always seem to see characters suffering from memory loss after an accident or head injury. In fact, this type of memory loss is often mild and temporary, rarely resulting in permanent damage.
More common causes of amnesia are less dramatic to portray on television and in movies. A stroke is commonly associated with the development of amnesia, as well as other medical conditions that cause a loss of oxygen to the brain. Heart attacks, severe asthma or other respiratory disorders, and constant inhalation of other gases can cause permanent damage and amnesia. Brain tumors and inflammation of brain tissue can cause amnesia, and medical conditions such as Alzheimer’s can lead to the development of amnesia as one of the symptoms.
A very rare type of amnesia—and incidentally, another that’s a favorite of fiction and pop culture—is the type of amnesia brought on by a traumatic event or extreme stress. While it’s possible and that does happen, it’s much, much more rare than we’re often led to think.