Though forgetting your identity is a common plot device in movies and television, that's not generally the case in real-life amnesia. Instead, people with amnesia, also called amnestic syndrome, usually know who they are. But, they may have trouble learning new information and forming new memories.
Amnesia refers to the loss of memories, such as facts, information and experiences, caused by brain damage, disease, or psychological trauma. Amnesia can also be caused temporarily by the use of various sedatives and hypnotic drugs. The memory can be either wholly or partially lost due to the extent of damage that was caused.
The term amnesia is from Greek, meaning "forgetfulness"; from “a-”, which means "without", and “mnesis”, meaning "memory".
There are two main types of amnesia, namely, retrograde amnesia and anterograde amnesia.
Retrograde amnesia is the inability to retrieve information that was acquired before a particular date, usually the date of an accident or operation. In some cases the memory loss can extend back decades, while in others the person may lose only a few months of memory.
Anterograde amnesia is the inability to transfer new information from the short-term store into the long-term store. People with this type of amnesia cannot remember things for long periods of time. These two types are not mutually exclusive; both can occur simultaneously.
There are other types of amnesia, which include:
Transient global amnesia: Transient global amnesia (TGA) is a poorly understood condition. If you develop it, you will experience confusion or agitation that comes and goes repeatedly over the course of several hours. You may experience memory loss in the hours before the attack, and you will probably have no lasting memory of the experience. Scientists think that TGA occurs as the result of seizure-like activity or a brief blockage of the blood vessels supplying your brain. It occurs more frequently in middle-aged and older adults.
Infantile amnesia: Most people can’t remember the first three to five years of life. This common phenomenon is called infantile or childhood amnesia.
Normal memory function involves many parts of the brain. Any disease or injury that affects the brain can interfere with memory.
Amnesia can result from damage to brain structures that form the limbic system, which controls your emotions and memories. These structures include the thalamus, which lies deep within the centre of your brain, and the hippocampus, situated within the temporal lobes of your brain.
Amnesia caused by brain injury or damage is known as neurological amnesia. Possible causes of neurological amnesia include:
Brain inflammation (encephalitis) as a result of an infection with a virus such as herpes simplex virus, as an autoimmune reaction to cancer somewhere else in the body (paraneoplastic limbic encephalitis), or as an autoimmune reaction in the absence of cancer
Lack of adequate oxygen in the brain, for example, from a heart attack, respiratory distress or carbon monoxide poisoning
Long-term alcohol abuse leading to thiamin (vitamin B-1) deficiency (Wernicke-Korsakoff syndrome)
Tumours in areas of the brain that control memory
Degenerative brain diseases, such as Alzheimer's disease and other forms of dementia
Certain medications, such as benzodiazepines or other medications that act as sedatives
Head injuries that cause a concussion, whether from a car accident or sports, can lead to confusion and problems remembering new information. This is especially common in the early stages of recovery. Mild head injuries typically do not cause lasting amnesia, but more-severe head injuries may cause permanent amnesia.
Another rare type of amnesia, called dissociative (psychogenic) amnesia, stems from emotional shock or trauma, such as being the victim of a violent crime, military combat, a natural disaster, a terrorist act, sexual or other abuse.
Any intolerable life situation that causes severe psychological stress and internal conflict can lead to some degree of amnesia. Psychological stressors are more likely to disrupt personal, historical memories rather than interfere with laying down new memories.
The chance of developing amnesia might increase if you've experienced:
Brain surgery, head injury or trauma
Amnesia varies in severity and scope, but even mild amnesia takes a toll on daily activities and quality of life. The syndrome can cause problems at work, at school and in social settings.
It may not be possible to recover lost memories. Some people with severe memory problems need to live in a supervised situation or extended-care facility.
The following are common symptoms of amnesia:
The ability to learn new information is impaired in anterograde amnesia.
The ability to remember past events and previously familiar information is impaired in retrograde amnesia
False memories may be either completely invented or consist of real memories misplaced in time, in a phenomenon known as confabulation.
Uncoordinated movements and tremors indicate neurological problems.
Confusion or disorientation may occur.
There may be problems with short-term memory, partial or total loss of memory
The person may be unable to recognize faces or locations.
Isolated memory loss doesn't affect a person's intelligence, general knowledge, awareness, attention span, judgment, personality or identity. People with amnesia usually can understand written and spoken words and can learn skills such as bike riding or piano playing. They may understand they have a memory disorder.
Being a little forgetful is completely different to having amnesia. Amnesia refers to a large-scale loss of memories that should not have been forgotten.
Amnesia isn't the same as dementia. Dementia often includes memory loss, but it also involves other significant cognitive problems that lead to a decline in daily functioning.
A pattern of forgetfulness is also a common symptom of mild cognitive impairment (MCI), but the memory and other cognitive problems in MCI aren't as severe as those experienced in dementia.
When to see a doctor
Anyone who experiences unexplained memory loss, head injury, confusion or disorientation requires immediate medical attention.
A person with amnesia may not be able to identify his or her location or have the presence of mind to seek medical care. If someone you know has symptoms of amnesia, help the person get medical attention.
How is Amnesia Diagnosed?
Amnesia can be diagnosed by your doctor or a neurologist. He or she will need to rule out other possible causes of memory loss, including dementia, Alzheimer's disease, depression, or a brain tumour.
They will take a detailed medical history, which may be difficult if the patient does not remember. Family members or caregivers may need to be present.
Your doctor may also use cognitive tests to check your memory. They may also order other diagnostic tests. For example, they may use an MRI or CT scan to check for signs of brain damage. They may use blood tests to check for nutritional deficiencies, infections, or other issues. They may also perform tests to check for seizures.
How is Amnesia Treated?
To treat amnesia, your doctor will focus on the underlying cause of your condition.
Chemically induced amnesia, from alcohol for example, can be resolved through detoxification. Once the drug is out of your system, your memory problems will probably subside.
Amnesia from mild head trauma usually resolves without treatment over time. Amnesia from severe head injury may not recede. However, improvements usually occur within six to nine months.
Amnesia from dementia is often incurable. However, your doctor may prescribe medications to support learning and memory.
Psychotherapy can help some patients. Hypnosis can be an effective way of recalling memories that have been forgotten.
Family support is crucial. Photographs, smells, and music may help.
If you have persistent memory loss, your doctor may recommend occupational therapy. This type of therapy can help you learn new information and memory skills for daily living. Your therapist can also teach you how to use memory aids and techniques for organizing information to make it easier to retrieve.
Malnutrition or Wernicke-Korsakoff syndrome can involve memory loss due to a thiamin (vitamin B1) deficiency, so targeted nutrition can help. Whole grain cereals, legumes (beans and lentils), nuts, lean pork, and yeast are rich sources of thiamin.
Coping and Support
Living with amnesia can be frustrating for those with memory loss, and for their family and friends, too. People with more-severe forms of amnesia may require direct assistance from family, friends or professional caregivers.
It can be helpful to talk with others who understand what you're going through, and who may be able to provide advice or tips on living with amnesia. Ask your doctor if he or she knows of a support group in your area for people with amnesia and their loved ones.
Because damage to the brain can be a root cause of amnesia, it's important to take steps to minimize your chance of a brain injury. Examples include:
Avoid excessive alcohol use.
Wear a helmet when bicycling and a seat belt when driving.
Treat any infection quickly so that it doesn't have a chance to spread to the brain.
Seek immediate medical treatment if you have any symptoms that suggest a stroke or brain aneurysm, such as a severe headache or one-sided numbness or paralysis.
Stay mentally active throughout your life. For instance, take classes, explore new places, read new books, and play mentally challenging games.
Stay physically active throughout your life.
Eat a heart-healthy diet, including fruits, vegetables, whole grains, and low-fat proteins.
Tips for Coping with a Poor Memory
Keep everyday items, such as car keys, in the same place and try to do things in the same order each time.
Write information down, and keep paper and a pencil near the phone.
Keep a diary at home as well as at work to remind you to do daily tasks.
Use an alarm to help you remember to do something in the future, such as taking something out of the oven.
Repeat important information you need to remember back to someone.