The Four Best-Known Types of Amnesia

Amnesia is the loss of memories, including facts, experiences, and information. Despite what movies suggest, most people who experience amnesia do not forget who they are but have a hard time remembering things from the past or forming new memories. There are several types of amnesia, each with unique causes and effects. In most cases, there is no cure for amnesia, particularly if it develops due to damage to the parts of the brain that are necessary for proper memory formation.

Diagnosis

Diagnosing amnesia typically involves an evaluation of other causes of memory loss to rule out dementia, Alzheimer’s disease, or a brain tumor. The doctor will take a complete medical history and attempt to get a thorough understanding of the type and degree of memory loss. People experiencing amnesia are not always able to reliably report these things, so it is common for a trusted family member or friend to be present during the evaluation. The physician will carry out neurological and cognitive tests, along with diagnostic tests, including CT scans, MRIs, and blood panels.

Retrograde Amnesia

Retrograde amnesia is the loss of information acquired before the incident causing amnesia occurred. In other words, the person may not remember autobiographical specifics from their past or facts they previously learned. Retrograde amnesia has fascinated the medical community for over a century and is still not well understood.

Causes of Retrograde Amnesia

The most common identified cause of retrograde amnesia is a desc=”Retrograde Amnesia for Facts and Events”]brain injury . One small study looked at hippocampal formation lesions and connected them to retrograde amnesia concerning autobiographical data. Removal of the temporal lobe and temporal lobe infarctions have also led to retrograde amnesia, but these studies are somewhat incomplete and difficult to interpret, primarily due to small sample sizes.

Anterograde Amnesia

Another type of amnesia is anterograde amnesia. Anterograde amnesia is when the person experiencing amnesia has problems with short-term memory. People with anterograde amnesia may remember their childhood and other deep, ingrained memories while not being able to recall the date, what they had for breakfast, or who is the current president.

Causes of Anterograde Amnesia

Recent research suggests that anterograde amnesia may be caused by something interrupting the memory, but what causes this interruption is unknown. Studies demonstrate that some people with anterograde amnesia can retain new information longer than others, but this retention was profoundly affected if new information was introduced following the initial learning.

Transient Global Amnesia

Another type is transient global amnesia. This is an episode of memory loss and confusion that comes on suddenly. Someone experiencing transient global amnesia is not able to make new memories but typically remembers who they are and recognizes loved ones. One of the interesting things about this type is that it tends to resolve on its own after several hours, and the person will not remember the incident.

Causes of Transient Global Amnesia

There is no clearly identified cause of transient global amnesia. Possible explanations include abnormalities in blood flow, hypoxia, ischemia, migraines, and epilepsy. Researchers have identified various events as possible triggers for an episode, including head trauma, physical exertion, sudden immersion in hot or cold water, and sexual intercourse.

Dissociative Amnesia

Dissociative amnesia may be diagnosed when a person cannot remember important information about their life, specifically biographical data. In rare cases, a person experiences a dissociative fugue, forgetting everything about who they are. They may even move and start a new life with a different identity. Unlike other types, dissociative amnesia is classified as a mental illness, during which normal functions breakdown.

Causes of Dissociative Amnesia

As dissociative amnesia is considered a mental illness, diagnostic criteria are spelled out in the DSM-5. The main symptom is being unable to recall important biographical information. To receive this diagnosis, the person must experience distress in daily life due to the symptoms, and the amnesia cannot be caused by substance abuse or any other physical or mental disorder. Dissociative amnesia is generally caused by trauma, abuse, or extreme stress.

Treatment

Treatment for amnesia depends on the type and cause. A popular approach is identifying and addressing underlying physical or mental issues while also working on strategies to accommodate for memory problems. Memory training is helpful, and occupational therapy can aid the recovery of lost skills. Smartphones and other technology are helpful for setting reminders, and notebooks, photographs, and calendars are also beneficial.