Amnesia refers to the loss of memories, such as facts, information and experiences. Though having no sense of who you are is a common plot device in movies and television, real-life amnesia generally doesn't cause a loss of self-identity. Instead, people with amnesia — also called amnestic syndrome — are usually lucid and know who they are, but may have trouble learning new information and forming new memories. Amnesia can be caused by damage to areas of the brain that are vital for memory processing. Unlike a temporary episode of memory loss (transient global amnesia), amnestic syndrome can be permanent. There's no specific treatment for amnesia, but techniques for enhancing memory and psychological support can help people with amnesia and their families cope.
Complications of Amnesia
Amnestic syndrome 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.
Causes of Amnesia
Normal memory function involves many parts of the brain, and any disease or injury that affects the brain can interfere with the intricacies of 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 center of your brain, and the hippocampal formations, which are located within the temporal lobes of your brain. An amnestic syndrome caused by brain injury or damage is known as neurological or organic amnesia. Possible causes of neurological amnesia include:
Head injuries, such as those sustained in car accidents, can lead to confusion and problems remembering new information, especially in the early stages of recovery — but usually don't cause severe amnesia. Another rare type of amnesia, called psychogenic or dissociative amnesia, stems from emotional shock or trauma, such as being the victim of a violent crime. In this disorder, a person may lose personal memories and autobiographical information, usually for just a brief time.)
Signs & Symptoms of Amnesia
The two main features of amnesia are:
Most people with amnestic syndrome have problems with short-term memory — they can't retain new information. Many also have some degree of impaired memory recall. Recent memories are most likely to be lost, while more remote or deeply ingrained memories may be spared. Someone may recall experiences from childhood or know the names of past presidents, but not be able to name the current president or remember what month it is or what was for breakfast. The memory loss doesn't affect a person's intelligence, general knowledge, awareness, attention span, judgment, personality or identity. People with amnestic syndrome usually can understand written and spoken words and can learn skills such as bike riding or piano playing. They may also understand that they have a memory disorder. 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 the ability to carry out daily activities. 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.
Additional signs and symptoms
Depending on the cause of the amnesia, other signs and symptoms may include:
Diagnosis of Amnesia
To diagnose amnesia, a doctor will do a comprehensive evaluation to rule out other possible causes of memory loss, such as Alzheimer's disease, dementia, depression or brain tumor.
The evaluation starts with a detailed medical history. Because the person with memory loss may not be able to provide thorough information, a family member, friend or another caregiver generally takes part in the interview as well. The doctor will ask many questions to understand the memory loss. Issues that might be addressed include:
The physical examination may include a neurological exam to check reflexes, sensory function, balance and other physiological aspects of the brain and nervous system.
The doctor will test the person's thinking, judgment, and recent and long-term memory. He or she will check the person's knowledge of general information — such as the name of the current president — as well as personal information and past events. The memory evaluation can help determine the extent of memory loss and provide insights about what kind of help the person may need.
Diagnostic imaging tests — including magnetic resonance imaging (MRI), computerized tomography (CT) and electroencephalogram (EEG) — may be ordered to look for damage or abnormalities in the brain. Blood tests can check for infection, nutritional deficiencies or other issues.
Treatments of Amnesia
Treatment for amnesia focuses on techniques and strategies to help make up for the memory problem.
A person with amnesia may work with an occupational therapist to learn new information to replace what was lost, or to use intact memories as a basis for taking in new information. Memory training may also include a variety of strategies for organizing information so that it's easier to remember and for improving understanding of extended conversation.
Many people with amnesia find it helpful to use a personal digital assistant (PDA), such as a Palm Treo, BlackBerry or iPhone. With some training and practice, even people with severe amnesia can use these electronic organizers to help with day-to-day tasks. For example, they can program the PDA to remind them about important events or to take medications. Low-tech memory aids include notebooks, wall calendars, pill minders and photographs of people and places.
Medications or supplements
No medications are currently available for treating most types of amnestic syndrome. Because Wernicke-Korsakoff syndrome involves a lack of thiamin, treatment includes replacing this vitamin and providing proper nutrition. Although treatment, which also needs to include alcohol abstinence, can help prevent further damage, most people won't recover all of their lost memory. Researchers are investigating several neurotransmitters involved in memory formation, which may one day lead to new treatments for memory disorders. But the complexity of the brain processes involved makes it unlikely that a single medication will be able to resolve memory problems.
Prevention of Amnesia
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. For example:
When to seek Medical Advice
Anyone who experiences unexplained memory loss, a 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, don't hesitate to help the person get medical attention.