You’ve read it a million times. The heroine (or hero) has no memory of who she is. No name. No remembered family. No past. Amnesia, says the doctor. And the story takes off. She (or he) attempts to recover her name. Her family. Her past. A little frightened and a lot intrigued, you are hooked.
You’ve read it so many times, it’s entertaining but not surprising. However, reality might surprise you.
Over the last month we’ve been talking about memory. In my post “What Do You Remember and How” you learned about the study of memory, the stages of memory, and the types of memory. “Do You Have a Terrible Memory?” discussed why you forget, the types of forgetting, and what normal forgetting is. You also learned that there were two umbrella terms that describe abnormal types of forgetting: Amnesia and Dementia.
You may be like me. You’ve read so many stories and seen so many movies or television shows whose characters suffered amnesia that you think you understand what it is. You could be wrong.
Do You Know What It Is?
Amnesia is total or partial loss of the ability to recall experiences or events that happened in the preceding few seconds, in the preceding few days, or further back in time.MerckManuals.com
You knew that, right? After all, that’s what the big and little screen and novels say. But did you know that people with amnesia rarely forget their name and their motor skills? Remember, I said memory is complex? So is forgetting.
What Causes Amnesia?
That’s a huge subject. Because we store our memories in bits and pieces throughout our brains, damage to any part of the brain can cause one or another form of amnesia. The list of things that can damage your brain is a little frightening.
- A nutritional disorder, particularly thiamin deficiency
- A severe head injury that affects the brain, a concussion or severe trauma (mild head injuries rarely cause permanent amnesia)
- Disorders that reduce the supply of blood or nutrients to the brain (including strokes and cardiac arrest)
- A brain infection (encephalitis)
- Disorders that reduce the supply of blood, oxygen, or nutrients to the brain)
- Alcohol abuse (both short term and chronic forms of alcohol abuse can cause amnesia)
- A brain tumor
- Severe mental stress, such as an emotional shock or trauma from physical or sexual abuse, or being the victim or witness of a violent crime
- Use of certain drugs, such as some antidepressants, muscle relaxants, or opioids, and amphotericin B or lithium
- Degenerative brain diseases, such as Alzheimer’s disease and other forms of dementia
- Electroconvulsive therapy
- Damage to the thalamus or hippocampus (parts of the brain and limbic system responsible for memory)
The Five Types of Amnesia
Retrograde Amnesia—In this type of forgetting, you lose existing memories. Typically, it affects your most recent memories first.
Anterograde Amnesia—with this kind of memory loss you cannot form new memories such as during an alcoholic or drug-induced blackout.
Transient Global Amnesia (TGA)—is an abrupt onset of anterograde amnesia that lasts from one to eight hours and affects people ages 40 to 80 years of age (average age is 61). Read more about TGA here.
Infantile Amnesia—the most common type of amnesia is the loss of memory of early childhood. Most people cannot remember the first three to five years of life.
Dissociative Amnesia—in this rare form of forgetting, the information lost would normally be part of conscious awareness and you might call it autobiographic memory. Read more here
How is Amnesia Diagnosed?
When someone arrives in the emergency room with a sudden memory loss, the doctor often orders an MRI or CAT scan to check for brain damage from a stroke or tumor. The doctors will also check blood work and take a detailed history.
Often a neurologist or neuropsychologist will perform a cognitive behavior test. This usually is a series of questions, some with multiple-step instructions or a list of three or more items which you’re asked to repeat back at various times during the test.
Do people with Amnesia Forget Everything?
When people suffer from sudden memory loss, the memories that they lose are generally what are known as episodic or explicit –they forget events and facts. They do not lose their implicit or procedural memory, which is what allows us to perform functions such as operating a cell phone or riding a bike.Improve Memory
Most often people suffering from sudden memory loss remember their name, their spouse, their dog. But they have difficulty with everyday activities because they can’t remember where they are going or what they’ve already done or said. They get frightened and frustrated and confused.
How Long Does Amnesia Last?
Recovery depends upon the severity of the disease or trauma that caused the amnesia. Most people recover their memories in time. In amnesia caused by some medications, recovery can be within minutes. Other cases may require days, months, or even years to recover. Sometimes the person never recovers their memories.
How Do You Treat Amnesia
If there’s a specific and known cause of amnesia, the cause will be treated. There’s no medication specific to amnesia. As I said above, often no treatment is necessary. Occupational therapy teaches skills and methods for dealing with memory loss. Sometimes, psychotherapy helps people adjust to memory loss and move forward.
But What About Dementia?
Dementia is more than forgetting. With dementia the memory loss is progressive and accompanied by cognitive problems that lead to a decreased ability to perform activities of daily living. Remember dementia is another umbrella term. We’ll discuss that and specific diseases soon.
Want to Know More?
My sources for this post include the MayoClinic.org, the Merck Manual, healthline.com, and the NIH. If you choose other sources, verify that the information is based on medical science. You may also wish to ask your doctor for more information.
Remembering and Forgetting
Remembering and forgetting are complex issues. And story books and movies aside, amnesia is frightening to everyone involved. This post skims over this information in an effort to answer questions and point you to more answers. If you have concerns about yourself, a friend, or family member, please consult your physician. Otherwise, I’m happy to answer your questions and would love to know if you knew about amnesia.