Amnesia is a type of memory loss that affects your ability to make, store, and retrieve memories. Retrograde amnesia affects memories that were formed before the onset of amnesia. Someone who develops retrograde amnesia after a traumatic brain injury may be unable to remember what happened in the years, or even decades, prior to that injury.
Retrograde amnesia is caused by damage to the memory-storage areas of the brain, in various brain regions. This type of damage can result from a traumatic injury, a serious illness, a seizure or stroke, or a degenerative brain disease. Depending on the cause, retrograde amnesia can be temporary, permanent, or progressive (getting worse over time).
With retrograde amnesia, memory loss usually involves facts rather than skills. For example, someone might forget whether or not they own a car, what type it is, and when they bought it — but they will still know how to drive.
Retrograde vs. anterograde amnesia
The two main types of amnesia are anterograde and retrograde.
People with anterograde amnesia have trouble making new memories after the onset of amnesia. People with retrograde amnesia have trouble accessing memories from before the onset of amnesia.
These two types of amnesia can coexist in the same person, and often do.
Temporally graded retrograde amnesia
Retrograde amnesia is usually temporally graded, which means that your most recent memories are affected first and your oldest memories are usually spared. This is known as Ribot’s law.
The extent of retrograde amnesia can vary significantly. Some people may only lose memories from the year or two prior to having the injury or disease. Other people may lose decades of memories. But even when people lose decades, they typically hang on to memories from childhood and adolescence.
- not remembering things that happened before the onset of amnesia
- forgetting names, people, faces, places, facts, and general knowledge from before the onset of amnesia
- remembering skills like riding a bike, playing the piano, and driving a car
- retaining older memories, especially from childhood and adolescence
Someone with this condition may or may not be able to make new memories and learn new skills.
Focal retrograde amnesia
Focal retrograde amnesia, also known as isolated or pure retrograde amnesia, is when someone only experiences retrograde amnesia with few or no symptoms of anterograde amnesia. This means that the ability to form new memories is left intact. This isolated memory loss doesn’t affect a person’s intelligence or ability to learn new skills, like playing the piano.
Dissociative (psychogenic) amnesia
This is a rare type of retrograde amnesia resulting from an emotional shock. It’s not caused by damage to the brain, like other types of retrograde amnesia. It’s purely a psychological response to trauma. It’s often caused by a violent crime or other violent trauma and is usually only temporary. Symptoms include:
- being unable to remember things that happened before a traumatic event
- possibly being unable to recall autobiographical information
Retrograde amnesia can result from damage to different parts of the brain responsible for controlling emotions and memories. These include the thalamus, which is deep in the center of the brain, and the hippocampus, which is in the temporal lobe.
There are several conditions that can cause retrograde amnesia. These include:
Traumatic brain injury
Most traumatic brain injuries are mild, resulting in concussion. But a severe injury, like a serious blow to the head, can damage the memory-storing areas of the brain and lead to retrograde amnesia. Depending on the level of damage, the amnesia could be temporary or permanent. Check out the best traumatic brain injury blogs of the year.
Thiamine deficiency, which is typically caused by chronic alcohol misuse or serious malnutrition, can lead to a condition called Wernicke encephalopathy. If left untreated, Wernicke encephalopathy progresses into a condition called Korsakoff psychosis, which presents with both anterograde and retrograde amnesia. Learn the symptoms of a vitamin B deficiency.
Encephalitis is inflammation in the brain caused by a viral infection, such as herpes simplex. It can also be caused by a cancer-related or non-cancer-related autoimmune reaction. This inflammation can cause damage to the memory-storing parts of the brain.
Both large strokes and repeated small strokes can cause damage to the brain. Depending on where the damage occurs, memory problems may result. It’s common for strokes to lead to memory problems and even dementia. Two types of memory that can be affected by stroke include verbal memory and visual memory.
Any type of seizure can cause damage to the brain and cause memory problems. Some seizures affect the whole brain and some only affect a small area. Seizures in certain parts of the brain, especially the temporal and frontal lobes, are a common cause of memory problems in people with epilepsy.
Cardiac arrest causes people to stop breathing, which means their brain may be deprived of oxygen for several minutes. This can lead to serious brain damage, which may cause retrograde amnesia or other cognitive deficits.
To diagnose retrograde amnesia, your doctor will need to perform a full medical exam to look for all the possible causes of memory loss. It’s best to have a loved one help communicate with the doctor, especially if you’re forgetting or confusing the details of your medical history. Your doctor will need to know what medications you’re taking and any past health problems, like seizures, strokes, or infections.
Your doctor may perform a number of different diagnostic tests, such as:
- imaging tests (CT scan or MRI scan) to look for brain injuries or abnormalities
- blood tests to check for nutritional deficiencies and infections
- a neurological examination
- cognitive tests to evaluate short- and long-term memory
- an electroencephalogram to check for seizure activity
There are no specific medications used to treat retrograde amnesia. Generally, your treatment will focus on the underlying cause of the amnesia. For example, if you have epilepsy, you and your doctor will work to reduce your number of seizures.
Currently no cures for Alzheimer’s disease and other degenerative dementias exist. However, there are some medications that may slow the progression of Alzheimer’s disease. Treatment for other types of dementia generally focus on support and coping.
Some people with amnesia work with an occupational therapist to learn new information and try to replace what was lost. They work with the therapist to use their older, intact memories as a basis for storing new memories. Therapists can help people develop organizational strategies that make it easier to remember new information. It’s also possible to develop conversational techniques that can help people improve social functioning.
Psychotherapy may help to improve memories lost because of traumatic events. It can also help those with other forms of amnesia to cope with the loss of memory.
Many people with amnesia benefit from learning to use new technology, such as smartphones and tablets. With training, people with severe amnesia can use technology to help them organize and store information. Smartphones and such are particularly helpful for people with trouble making new memories. As well, they can also be used as storage devices for old memories. Photographs, videos, and documents can make good reference material.
Depending on the cause, retrograde amnesia might get better, worse, or remain fixed throughout life. It’s a serious condition that can present challenges, so the help and support of loved ones is often important. Depending on the severity of the amnesia, a person may regain their independence or they may need more care.