Definition
Amnesia refers to the loss of existing memories or an inability to create new memories, or both (Mayo Clinic). There are several different types of amnesia, including retrograde, anterograde, and psychogenic or dissociative amnesia. Amnesia can have functional (psychological) or organic (damage or injury) causes (Medical News Today).
Amnesia can be temporary or permanent. However, unlike the plotlines of many movies and books, amnesia doesn’t usually result in a total loss of identity. Most people with amnesia are lucid and might understand that they have a memory problem (Mayo Clinic).
Types of Amnesia
Retrograde Amnesia: This type of amnesia refers to an inability to recall past events and previously known information. In most cases older memories are less affected than recent ones. However, people with retrograde amnesia can usually learn and form new memories (Healthline).
Anterograde Amnesia: This type of amnesia involves an inability to create new memories or learn new things; also known as short-term memory loss. Most people with amnesia have this type (Mayo Clinic). Someone with anterograde amnesia can remember childhood events, but might not be able to remember what day it is or what they last ate for lunch.
Generally, older and more deeply ingrained memories are better preserved than newer memories, and when memory returns, the older memories come back first (Mayo Clinic).
Dissociative Amnesia: This condition refers to significant memory loss as a result of psychological trauma (NAMI). Psychogenic amnesia can be global, leading to a complete but temporary loss of identity, or situation-specific, which is the result of a severely traumatic or stressful event. People with dissociative amnesia block out the information associated with a traumatic event as a defense or self-protection mechanism (WebMD). This type of amnesia differs from retrograde and anterograde amnesia in that the memories in psychogenic amnesia still exist but are buried deeply cannot be recalled. However, the memories can resurface if triggered by another stressful event.
Causes of Amnesia
Amnesia has many causes, including damage or injury to the brain, dementia, alcohol and drug use, and severe stress (Healthline). A loss of oxygen to the brain can also cause amnesia. Drugs used for moderate sedation, including those used for certain medical procedures, lead to a loss of memory of the procedure even if the person is able to communicate with medical personnel during the event (Emedicine).
Sedation and oxygen loss to the brain are among the organic causes of amnesia. Other organic causes include (Mayo Clinic):
- Degenerative diseases including Alzheimer’s disease and dementia
- Head injuries
- Stroke
- Tumors
- Seizures
- Encephalitis
- Long-term alcohol abuse
Functional causes of psychogenic amnesia include depression and severely stressful events, such as being the victim of a violent crime. Other possible causes include (WebMD):
- Childhood abuse
- Natural disasters
- War
- Terrorist attacks
- Post-traumatic stress disorder (PTSD)
It should be noted that dissociative amnesia is rare and is usually temporary, lasting from a few seconds to a few hours. In rare cases, it can last longer, up to months or even years (Mayo Clinic).
Diagnosis
To diagnose amnesia, a neurologist or other health professional will first need to determine the cause of the memory loss, which can be difficult if the patient is having trouble with memory (Medical News Today). Family members can be helpful with this part of the diagnostic process. Tests such as MRI (magnetic resonance imaging), CT (computerized tomography) or an EEG (electroencephalogram) can be useful in determining the extent of any brain damage that might be present.
A physical exam will usually be carried out to test the patient’s reflexes, balance and sensory function, and cognitive testing can assess judgment, thinking, and the extent of the memory loss.
Treatment
Many cases of amnesia resolve spontaneously with time (Medical News Today), particularly those derived from head trauma. However, if there is an underlying injury, disease or psychological condition, it should be treated as soon as possible.
In cases of psychogenic or dissociative amnesia, treatment goals include relieving the symptoms and then helping the person cope with the trauma or stress that caused the amnesia (WebMD). Psychotherapy, medications, cognitive therapy, and even hypnosis can be useful for patients with psychogenic amnesia.
Treatments for organically derived amnesia usually focus on developing strategies for dealing with or compensating for the memory loss (Mayo Clinic). There are currently no medications that can restore memories. An occupational therapist can work directly with patients to find technologies and techniques to replace memories that have been lost or to organize information in useful ways. Modern smartphones and tablets as well as more traditional memory aids such as wall calendars, pill cases and notepads can all be very useful to amnesia patients to remind them of tasks to be done, medications to be taken, and important names, dates, and places.
Home care strategies for people suffering from amnesia include implementing strategies to prevent falls (fall detectors can be worn on a belt) and accidental door locks, as well as ensuring important phone numbers are posted near a telephone (News-Medical). A medical ID bracelet is also a useful device for patients with memory loss.
Prevention
Many organic causes of amnesia can be prevented by taking steps to reduce the risk of brain damage or injury (Mayo Clinic):
- Avoid excessive alcohol and drug use
- Wear helmets when cycling and motorcycling, headgear for contact sports and seatbelts when driving
- Be alert to signs and symptoms of stroke and do not wait to seek treatment for these symptoms
- Maintain cognition through continuous learning, reading, and physical activities (HealthLine).
Functional causes of amnesia may be difficult to prevent, but it can be helpful to seek treatment at the first sign of symptoms (WebMD). Anyone who has suffered a traumatic event, extended stress, or depression is at risk of dissociative amnesia, and immediate treatment through psychotherapy or counseling can help reduce the chances this type of amnesia will develop.
Conclusion
Amnesia refers to a partial or total loss of memory, usually due to physical or emotional trauma or degenerative disease. Amnesia is typically transient, lasting a few seconds to hours, but in rare cases can last longer and no matter the duration, amnesia can be quite distressing to both the patient and his or her caregivers. A thorough understanding of the various physical and psychological causes of amnesia and how they are treated can help patients either cope with the memory loss or resolve it.
