Retrograde amnesia: Forgetting your past completely
Imagine forgetting everything from the past decade and being completely unable to recall those years. In this article, we will find out what retrograde amnesia is, how it affects the brain, the different types, causes, diagnosis, treatments, and the outlook for those with retrograde amnesia.
What is retrograde amnesia?
Amnesia is a phenomenon that affects our memory. Retrograde amnesia is a type of amnesia that affects our long-term memories that were formed before the onset of amnesia. It is caused by damage to the memory-storage parts of our brain, located in various regions. The type of memory loss involved with retrograde amnesia is more about losing facts rather than losing skills. For example, you may forget whether you own a bike and/or what it looks like, but you won’t forget how to ride a bike. It tends to affect the episodic memory, autobiographical memory, and declarative memory while keeping the procedural memory intact.
The difference between retrograde amnesia and anterograde amnesia
Unlike with anterograde amnesia where there is an inability to form new memories, retrograde amnesia allows for very specific information to be forgotten- a single event, for example. Someone who has anterograde amnesia could play the piano (implicit memory) but wouldn’t be able to describe their first piano recital (explicit memory). Someone who has retrograde amnesia could probably describe their first piano recital if it happened a long time ago and remember how to play the piano.
What brain areas are affected
Retrograde amnesia goes for our most recent memories first. However, the more severe the amnesia, the farther back in time the memory loss will go. This happens because the neural pathways in our brain that involve never memories are not as strong as the neural pathways that involve our older memories.
Retrograde amnesia is the result of damage to different parts of the brain that are responsible for controlling our emotions and our memories. The hippocampus, which is located in the temporal lobe, which is known to look like a little seahorse in our brain, is in charge of classifying our memories- especially our long-term memory. The thalamus, which is in the center of our brain, transmits the majority of our perceived sensory information (visual, auditory, and tactile) so that the information can be processed in other parts of the brain. It’s used for our motor control, as well.
In order for memory loss to occur, there must be damage to more than just one part of the brain. That means that if you have a language-related memory loss, the hippocampus isn’t only damaged, but also Broca’s area, a part of the brain which houses language information, is also damaged.
Types of Retrograde Amnesia
There are several different types of retrograde amnesia and each type comes with its own symptoms.
Temporally graded retrograde amnesia is the most common type of retrograde amnesia. This means that your most recent memories are the memories most affected and your older memories are usually left unimpaired. This is known as Ribot’s Law. Some people who are affected by a temporally graded retrograde amnesia may only lose memory from the one or two years prior to the injury or disease that caused the amnesia. Someone who has temporally graded retrograde amnesia may not be able to form new memories or learn new skills. Other people lose decades of memories.
Some symptoms may include:
- Being unable to remember things that happened before the onset of amnesia (before the injury or disease)
- Remembering skills like playing the piano, driving a car, and riding a bike
- Forgetting the names of people, faces, places, facts, and general knowledge that you knew before the start of having amnesia
- Remembering older memories from childhood and adolescence
Focal retrograde amnesia, also known as pure or isolated retrograde amnesia, is an isolated memory loss that happens when someone experiences retrograde amnesia with few or no symptoms of anterograde amnesia. The ability to form new memories is left undamaged and your ability to learn new skills, like riding a bike, isn’t affected. It’s an inability to retrieve remote information in the face of normal ability in order to learn new information without any other psychological or cognitive impairment. It’s a relatively mild form of retrograde amnesia because the majority of people who suffer from it are able to lead lives without much set back due to the amnesia.
Dissociative retrograde amnesia, also known as psychogenic amnesia, is caused by extreme emotional shock, not damage to the brain like other forms of retrograde amnesia. It’s simply a psychological response to trauma. It can be caused by a violent crime or violent trauma and is often temporary.
- Being unable to recall autobiographical information, such as your own name
- Being unable to remember things that happened before the traumatic event
Possible Causes of Retrograde Amnesia
Possible causes of retrograde amnesia include a traumatic brain injury, a serious illness, a seizure or a stroke, or a degenerative brain disease. Depending on the cause, the amnesia can be temporary, permanent, or progressive (it worsens over time).
Typically people who get retrograde amnesia from a traumatic brain injury (TBI) can’t remember what happened in the years, possibly even decades, leading up to the brain injury. Although the majority of TBI’s are mild, usually ending with a concussion, the serious ones can cause such severe damage to the memory-storing parts of our brain that the amnesia could be temporary or permanent. One study on a 15-year-old boy who hit his head and completely lost consciousness showed that he was unable to remember anything, but could play the piano, which shows that his procedural memory was still intact. He gradually recovered some memories within the few days following his TBI, but he has autobiographical amnesia which shows he had issues remembering famous public facts and events for two years prior to the injury. This means that he couldn’t remember who won the Super Bowl the year before.
Encephalitis is brain inflammation due to a viral infection, like herpes simplex, or an autoimmune reaction, cancer and non-cancer related. This inflammation can cause damage to the memory-storing areas of our brain.
Thiamine deficiency, usually caused by habitual alcohol misuse or severe malnutrition, can lead to what is known as Wernicke encephalopathy. Essentially, a vitamin B deficiency. When Wernicke encephalopathy is left untreated, it leads to korsakoff psychosis, which leads to both anterograde and retrograde amnesia.
Cardiac arrest triggers people to stop breathing which means that their brain will be deprived of oxygen for a few minutes. When our brain is deprived of oxygen, this can provoke severe brain damage which leads to serious cognitive deficits as well as retrograde amnesia.
Alzheimer’s disease, along with other degenerative dementias, can lead to progressively worsening retrograde amnesia.
Strokes, both large and continually small, can lead to brain damage. They are the second most common cause of cognitive impairment, after dementia. Depending on where the brain damage is, memory problems can occur. Strokes can affect both verbal memory and visual memory.
Any type of seizure can cause brain damage and thus, cause memory problems. Some types of seizures affect the whole brain while others affect only a small area of the brain. In people with epilepsy, a chronic disorder that causes unprovoked and recurrent seizures, memory problems are often due to seizures in the temporal and frontal lobes.
Retrograde Amnesia Diagnosis
In order to diagnose retrograde amnesia, there needs to be a full medical exam performed by a doctor to look at all of the possible causes for the loss of memory. It helps to have someone with you who can communicate with the doctor and who knows your medical history- this way you don’t need to worry about forgetting or confusing any details.
A doctor can perform a number of tests. Some of those may include:
- Blood tests in order to check for any nutritional deficiencies and/or infections
- A neurological examination which is the assessment of sensory neuron and motor responses, like reflexes, and can include things like a physical exam and a review of the patient’s medical history.
- Imaging tests like a CT Scan or an MRI Scan in order to look for brain abnormalities or injuries. CT scans are the standard technique used for evaluating a brain injury in the emergency room. According to a clinical trial performed by the University of California, San Francisco, and the San Francisco General Hospital and Trauma Center, MRIs may be better at predicting the long-term outcomes for people with milder TBIs than a CT scan because an MRI reveals signs of brain injuries not seen in a CT scan.
- Cognitive tests in order to evaluate short-term and long-term memory. One test called the TYM test (Test Your Memory Test), involves ten tasks which involve the ability to copy a sentence, calculation, semantic knowledge, verbal fluency and recall ability. The TYM test has been tested on 540 cognitively healthy people and 139 people who were diagnosed with a mild cognitive impairment or Alzheimer’s disease.
- Using an electroencephalogram to check for seizure activity in the brain.
Retrograde Amnesia Treatment
There are no medications that exist specifically for retrograde amnesia. Instead, the treatment is more so focused on the underlying causes of amnesia. For example, someone with Alzheimer’s disease may take medication to slow down the progression of it. Or for example, someone with epilepsy will work on having fewer seizures which should, in turn, slow down the development of amnesia due to epilepsy.
Other types of treatment:
- Occupational therapy is used to help learn new information and to try to replace what was lost. An occupational therapist will help develop the older, more intact memories to help build a stronger basis for storing new memories by using organizational strategies that make remembering new information easier or developing conversational techniques to help improve social functioning.
- Psychotherapy, using therapy instead of medications, is used to help improve lost memories. Furthermore, it’s known to help people who have other forms of amnesia to cope with memory loss in general.
- Technology, like smartphones and tablets, is becoming a known treatment for retrograde amnesia because, with training, people who have severe memory issues can use technology to organize and store information. Technology can also be helpful to make new memories by taking pictures and videos to be used as reference material.
The outlook for people with retrograde amnesia
The outlook for people with retrograde amnesia depends on the cause of the amnesia in the first place. It can get better, worse, or stay the same throughout like. Depending on how severe the amnesia is, someone may be able to regain their independence or they may need more care from others.
Tips for patients and family members
- Stay patient and remain calm.
- Have a safe spot for your keys, wallet, and phone (for example, the mantel by the front door or the kitchen counter) where you always leave the most important things.
- Here is a list of great techniques to help improve memory!
- Write it down! Keep a notepad by the phone or computer.
- Use alarms to remind yourself to do things. For example, to take out the trash or take something out of the oven.
- Repeat back or tell someone else important information that you will need to remember. Not only does this help you know that you heard the information correctly, but it also increases the chances that you will be able to recall the information later on.
Have you or anyone you know experienced retrograde amnesia? What did you do to help treat it? Let us know in the comments below!