Retrograde amnesia takes place when a subject is unable to recall memories from the past that happened prior to the accident or the disease leading to memory loss. Let’s explore the different aspects of this condition & understand the possible ways to treat it.
- What Is Retrograde Amnesia?
- Understanding Retrograde Amnesia
- Retrograde Amnesia At A Glance
- Difference Between Retrograde Amnesia & Anterograde Amnesia
- Types Of Retrograde Amnesia
- Causes Of Retrograde Amnesia
- Symptoms Of Retrograde Amnesia
- Diagnosis Of Retrograde Amnesia
- How To Treat Retrograde Amnesia?
- Tips To Prevent Retrograde Amnesia
- Help Is Available
What Is Retrograde Amnesia?
Mind Help explains “Retrograde amnesia (RA) is a type of mental health disorder where the memories formed prior to the onset of the condition get affected.” The psychiatric disorder is caused by damage to the memory-storage areas of the brain or hippocampus since the already existing long-term memories are stored in the neurons and synapses of different brain regions. This type of mental disorder usually occurs from the damage in the regions of the brain that is closely linked to declarative memory, such as the temporal lobe and prefrontal cortex. The damage may result from a blow to the head, a stroke, tumor, hypoxia (lack of oxygen in the brain), chronic alcoholism, etc. Retrograde amnesia can range from transient to permanent to progressive, depending on the reason (getting worse over time).
Because RA is frequently temporally graded, ancient memories are more accessible than events that occurred shortly before the trauma. Additionally, events close to the time of memory loss may never recover. The key reason behind this is the fact that neural pathways of newer memories are not as strong as older ones that have been strengthened with years of retrieval and reconsolidation. Additionally, with this condition, memory loss generally occurs revolving around the facts rather than skills. For example, a person might forget that he owns a car, however, that will not affect the person’s driving skills.
Understanding Retrograde Amnesia
A study 1 by psychiatrists Jonathan M. Reed and Larry R. Squire explains that RA “refers to loss of memory for information acquired before the onset of amnesia.” A person develops this condition after a traumatic brain injury, leading to the inability to remember the events of life that had happened in the years or even decades before the injury. The principal reason responsible for this condition is the damage caused to the memory-storage regions of the brain. Traumatic injury, a seizure, stroke, a serious illness or degenerative brain disease can lead to RA. Depending on the reason, this disorder can be temporary, permanent, or progressive.
Additionally, in this condition, the memory loss generally occurs catering to facts rather than skills. For example, a person might forget that he owns a car, however, that will not affect the person’s driving skills.
It must be noted that there is no actual cure for RA, exposing the victim’s memory to significant articles from their past may help to speed up the rate of recall.
Retrograde Amnesia At A Glance
- Retrograde amnesia (RA) is a type of mental health disorder where the memories formed prior to the onset of the condition get affected.
- Retrograde amnesia refers to the loss of information acquired before amnesia while anterograde amnesia (AA) is an impaired capacity for new learning.
- RA is usually the result of damage in different parts of the brain accountable for controlling emotions and memories.
- The condition or the severity of retrograde amnesia entirely depends on the cause.
- Traumatic injury, a seizure, stroke, a serious illness or degenerative brain disease can lead to RA.
- There is no actual cure for RA, exposing the victim’s memory to significant articles from their past may help to speed up the rate of recall.
Difference Between Retrograde Amnesia & Anterograde Amnesia
Retrograde amnesia refers to the loss of information acquired before amnesia while anterograde amnesia (AA) is an impaired capacity for new learning. According to a 2013 study 2 , there is “an orderly relationship between AA and RA, such that patients with more severe AA also had more extensive RA. In addition, RA was measurable only after AA reached a substantial level of severity.” In retrograde amnesia, a person is unable to remember events that have happened in the past, prior to the injury or the disease that caused the loss. Such patients are generally able to remember meanings and other actual information but are not able to recollect specific events or situations. On the other hand, when a person is unable to collect and retain new information but is capable to recall data and events that happened previously, it is known as anterograde amnesia.
While both are serious mental health disorders, the severity of RA is often symbolized by what memories are retained. The extent of memory impairment is determined by the extent of brain damage, that is, whether it is limited to the hippocampus or involves the temporal cortex. On the other hand, anterograde amnesia is usually a permanent condition and it is assumed to be caused by damage to the hippocampus section of the brain. It must be noted that both the conditions can be present in one individual, thereby, making it harder to deal with the condition. Also, the treatment of both conditions is significantly complex since there is no concrete method to treat both conditions.
Types Of Retrograde Amnesia
Retrograde amnesia can be divided into 2 categories, each of which are defined by different symptoms. Let us understand the various types of retrograde amnesia along with the symptoms.
1) Focal Retrograde Amnesia (FRA)
Focal retrograde amnesia, also known as isolated or pure RA, occurs when a patient only struggles with this condition with few or no symptoms of anterograde amnesia. Thus, the ability to form a new memory is left intact. It also does not hamper the subject’s intelligence or ability to learn new skills, like playing the piano. This syndrome is linked with various neurological disorders such as traumatic brain injury, encephalitis, hypoxia or epilepsy.
Research 3 shows that FRA is a rare neurocognitive condition that involves “an isolated loss of retrograde memory.” As per a 2008 study 4 , FRA can be caused by different events such as head injury, dissociative fugue, seizure, accident that don’t involve head injury, posttraumatic headache, acute distress, migraine attack and syncope. “FRA is a disorder characterised by a loss of memory function caused by a variety of events, including both physical and psychological injuries,” the researchers explain.
2) Dissociative (psychogenic) Amnesia
A rare type of RA, dissociative amnesia occurs due to emotional shock. Unlike other types of retrograde amnesia, it is not caused by any damage to the brain. It is defined as a psychological reaction to a traumatic event. According to a study, the condition is characterized by a retrospective gap in the memory catering to relevant personal information, usually pertaining to traumatic or stressful events. This form of memory loss goes beyond ordinary forgetfulness and is not the result of substance use or the consequence of a medical condition.
Thus, dissociative amnesia is usually caused by a violent crime or other violent trauma and is only a temporary condition. Symptoms include:
- Inability to recollect things that happened before the traumatic event
- Like unable to recall autobiographical information
Research 5 also indicates that dissociative amnesia may also cause dissociative fugue.
Read More About Dissociative Fugue Here
3) Temporally Graded Amnesia
Retrograde amnesia is normally temporally graded. It means that the person’s most recent memories are affected first while the oldest memories are usually spared. This is also known as Ribot’s law. The degree of this type of RA varies significantly. While some may lose memories from the year or two before any head injury, others can lose decades of memories. However, even then, such patients generally usually retain memories from childhood and adolescence. According to a 2002 study temporally graded retrograde amnesia (TGRA) is a condition involving premorbid memory loss, whereby information acquired recently is more damaged than information acquired more remotely. Someone with this condition may or may not be able to develop new memories and learn new skills.
Causes Of Retrograde Amnesia
The operation of normal memory involves many parts of the brain. Any disease or impairment that affects the brain can intervene with memory. RA is usually the result of damage in different parts of the brain accountable for controlling emotions and memories. There are several reasons that can cause this condition. The following are mentioned below.
1) Traumatic Brain Injury
On a general note, maximum brain injuries are mild, resulting in a concussion. A severe brain injury, such as a concussion, can, on the other hand, cause irreversible damage to the memory-storing areas of the brain, resulting in retrograde amnesia. Depending on the extent of damage, the amnesia could be a short-term or long-term condition. According to a 2018 study, traumatic brain injury (TBI) is known to facilitate the development of both anterograde amnesia and retrograde amnesia. While the first condition impairs learning and preservation of new information, RA gives rise to memory loss, especially of the events prior to the injury. Clinicians evaluate the severity of this condition by asking patients about their “last memory” prior to the injury. These assessments, however, do not consider memory for earlier life events.
2) Thiamine Deficiency
Thiamine 6 deficiency, which is mainly caused due to chronic alcohol misuse or serious malnutrition, can lead to a condition called Wernicke Encephalopathy 7 . However, if this condition is left untreated, it can progress into yet another condition called Korsakoff Psychosis. This condition is present in both retrograde and anterograde amnesia.
As per a study 8 , Korsakoff’s Syndrome is an amnestic disorder that involves both anterograde and retrograde amnesia. As with diencephalic lesions, the disorder is connected to long-term alcohol abuse, and thiamine deficiency has long been implicated in its development. The key features of this condition include the inability to learn new information or form new memories and the inability to retrieve old memories. Without thiamine supplementation, the deficiency leads to acute and reversible incidents of Wernicke Encephalopathy that can eventually lead to the more permanent condition of Korsakoff’s Syndrome.
Encephalitis 9 is defined as a condition whereby inflammation occurs in the brain due to a viral infection, such as herpes simplex 10 . It can also take place due to a cancer-related or non-cancer-related autoimmune reaction. This inflammation can hamper the memory-storing parts of the brain.
According to a study 11 , herpes simplex virus encephalitis (HSVE) mainly affects the medial and lateral temporal lobe and orbitofrontal cortices with bilateral or lateralized involvement. When damage occurs in the medial temporal lobe, the capacity to recall personally experienced and temporally specific events or episodes gets affected. Problems in encoding, storing, and retrieving events learned from the past and related to new information may also occur, marking retrograde and anterograde amnesias, respectively. Lesions to the dominant hemisphere’s temporal lobe are associated to semantic memory loss and anomia, while injuries to the prefrontal cortex and subcortical areas disrupt the linkages within these regions, and may also produce executive dysfunction.
4) Alzheimer’s Disease
Alzheimer’s disease and any other form of degenerative dementias can lead to progressive worsening retrograde amnesia. Currently, there are no cures or treatments addressing the concern.
Read More About Alzheimer’s Disease Here
Large strokes and repeated small strokes, both can cause injury to the brain. The problem catering to memory depends on where the damage is occurring. It’s usual for strokes to result in memory problems and even dementia. Verbal memory and visual memory are the two types of memories that can be affected by stroke.
As per a study 12 , a unilateral stroke to the brain is sufficient to cause significant retrograde memory impairment, with right-sided injuries affecting the recalling power of autobiographical events more than left-side injuries. Although it may cause relatively mild memory deficits, it can be temporally pervasive rather than defined by a traditional temporal gradient. Furthermore, the memory of events (both autobiographical and public) was weakened in patients who had had a stroke that included the hippocampus, but not in those whose strokes overlooked the concerned region.
Any type of seizure can cause harm to the brain followed by memory problems. Some seizures attack the whole brain while some only attack a small area. Seizures in some parts of the brain, especially the temporal and frontal lobes, leads to memory problems in people with epilepsy.
7) Cardiac Arrest
Since cardiac arrest hinders with the breathing process, chances are high that it may deprive the brain of oxygen for several minutes. As a result, serious damage in the brain can take place which may cause retrograde amnesia or other cognitive deficits.
Symptoms Of Retrograde Amnesia
As per Ribot’s Law 13 , RA is (generally) temporally graded. In simpler words, a subject’s most recent memories will be majorly affected first while keeping the oldest memories intact (usually).
The intensity of this disorder can alter significantly. For example, one individual may only lose memories from the year or two before the injury or disease, whilst another may lose decades of recollections. However, in the second case, the subject will probably hang on to memories from childhood and adolescence. With that being said, here are the symptoms of retrograde amnesia.
- The inability to remember things that had occurred before the onset of amnesia
- Unable to remember names, people, places, facts, faces and general knowledge prior to amnesia
- Ability to remembering skills like playing the piano, riding a bike, and driving a car
- Recalling old memories, especially from childhood and adolescence
Additionally, it must be noted that a subject with such a mental condition may or may not be able to create new memories and learn new skills.
Diagnosis Of Retrograde Amnesia
To diagnose RA, the doctor is entitled to perform a complete medical examination, thereby looking for all the potential causes leading to memory loss. Ideally, some close to the subject, like the subject’s family should communicate with the doctor, especially if the subject is forgetting or confusing the aspects of his/her medical history. Additionally, the doctor will ask about the current medication pattern and along with details of any past health problems, like seizures, strokes, or infections.
A doctor or a healthcare expert may perform multiple diagnostic tests, such as:
- Imaging tests like the CT scan or MRI scan to study brain injuries or abnormalities
- Blood tests to monitor nutritional deficiencies and infections
- A neurological examination
- Cognitive tests to assess short and long-term memory
- Carry out an electroencephalogram to check for seizure activity
How To Treat Retrograde Amnesia?
There is no specific medication to treat this disorder. However, the treatment generally focuses on the underlying cause of the amnesia. For example, if a subject has epilepsy, the doctor along with the subject will come up with a treatment plan to reduce the frequency of seizures.
Also, to date, there are no cures for Alzheimer’s disease and other degenerative dementias exist. However, there are a few medications that may slow down the progression of Alzheimer’s disease. Treatment for other types of dementia usually focuses on support and coping. Here are a few ways to treat retrograde amnesia.
1) Therapy Treatment
To treat RA, here are the following therapies as suggested by the experts or primary care physicians.
A. Occupational therapy
Individuals with RA go for therapy sessions with an occupational therapist to acquire new information while trying to replace the lost element. They sit with the therapist who helps them to use their older, intact memories as a foundation for storing new memories. Such therapists can also assist people to develop organizational strategies that will help the subject to remember new information. It’s also possible to promote the growth of conversational techniques that can help the subject to improve his/her social functioning. As per a 2018 study 14 , occupational therapy (OT) is one of the components of a multidisciplinary team approach that concentrates on facilitating participation in meaningful occupations as an essential element of healthcare. Generally, the idea of OT has been misunderstood among the public and even among healthcare professionals.
Psychotherapy is generally geared towards helping the subject to improve lost memories due to a traumatic event. It can also help the subject with other types of amnesia to cope with the loss of memory. A 2015 study 15 found formulation-driven psychological therapy using methods outlined by cognitive behavioral therapy (CBT) and acceptance and commitment therapy (ACT) for psychogenic amnesia can prove to be effective. It can help to improve anterograde and retrograde memory impairments as well.
Many people with retrograde amnesia gain from learning to use new technology, such as tablets or smartphones. With proper training, people with severe RA can utilize technology to help them prepare and store information. Additionally, apart from using it as a storage for new memories, one can also store old memories in the form of videos, pictures and documents that can work as good reference material.
Tips To Prevent Retrograde Amnesia
Given the fact that any injury to the brain can cause RA, it’s essential to take a few safety measures to minimize one’s chance of suffering any form of brain damage.
- Avoid unnecessary alcohol intake
- Make sure to wear a helmet when riding a bike and fasten the seat belt when driving.
- Treat any sort of infection quickly to avoid its chances from spreading to the brain.
- Seek immediate medical treatment if there are any symptoms suggesting a stroke or brain aneurysms, such as a severe headache or one-sided paralysis.
Help Is Available
The condition or the severity of retrograde amnesia entirely depends on the cause. It might get better, worse or remain fixed for one’s lifetime. No matter what, this mental health disorder is a serious condition that can present challenges. Thus make sure to help and support the loved ones as it is the severity of the condition that determines whether it is a temporary or a permanent ailment.References:
- Reed, J. M., & Squire, L. R. (1998). Retrograde amnesia for facts and events: findings from four new cases. The Journal of neuroscience : the official journal of the Society for Neuroscience, 18(10), 3943–3954. https://doi.org/10.1523/JNEUROSCI.18-10-03943.1998
- Smith, C. N., Frascino, J. C., Hopkins, R. O., & Squire, L. R. (2013). The nature of anterograde and retrograde memory impairment after damage to the medial temporal lobe. Neuropsychologia, 51(13), 2709–2714. https://doi.org/10.1016/j.neuropsychologia.2013.09.015
- Sehm, B., Frisch, S., Thöne-Otto, A., Horstmann, A., Villringer, A., & Obrig, H. (2011). Focal retrograde amnesia: voxel-based morphometry findings in a case without MRI lesions. PloS one, 6(10), e26538. https://doi.org/10.1371/journal.pone.0026538
- Stracciari, A., Fonti, C., & Guarino, M. (2008). When the past is lost: focal retrograde amnesia. Focus on the “functional” form. Behavioural neurology, 20(3), 113–125. https://doi.org/10.3233/BEN-2008-0222
- Sharma, P., Guirguis, M., Nelson, J., & McMahon, T. (2015). A Case of Dissociative Amnesia With Dissociative Fugue and Treatment With Psychotherapy. The primary care companion for CNS disorders, 17(3), 10.4088/PCC.14l01763. https://doi.org/10.4088/PCC.14l01763
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