Amnesia

 

Amnesia

Overview

Amnesia refers to the loss of memories, including facts, information and experiences. Movies and television tend to depict amnesia as forgetting your identity, but that's not generally the case in real life.

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 can be caused by damage to areas of the brain that are vital for memory processing. Unlike a temporary episode of memory loss, called transient global amnesia, amnesia can be permanent.

There's no specific treatment for amnesia, but treatment can be directed at the underlying cause. Tips to help enhance memory and get support can help people with amnesia and their families cope.

Symptoms

The two main features of amnesia are:

• Trouble learning new information.
• Trouble remembering past events and previously familiar information.

Most people with amnesia have problems with short-term memory, so they can't retain new information. Recent memories are most likely to be lost. More-remote or deeply ingrained memories may be spared.

For example, people may recall experiences from childhood or know the names of past presidents. But they may not be able to name the current president, know the month or remember what they ate for breakfast.

Isolated memory loss doesn't affect a person's intelligence, general knowledge, awareness or attention span. It also doesn't affect 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.

Amnesia isn't the same as dementia. Dementia often includes memory loss but also involves other problems with thinking that lead to a decline in daily functioning. These problems include having trouble with language, judgment and visual-spatial skills.

Memory loss also is a common symptom of mild cognitive impairment. This disorder involves memory and other cognitive problems that aren't as severe as those experienced in dementia.

Additional symptoms

Depending on the cause of the amnesia, other symptoms may include:

• False memories that are either completely invented or are real memories misplaced in time.
• Confusion or disorientation.

When to see a doctor

Anyone who experiences unexplained memory loss, head injury or confusion requires immediate medical attention.

People with amnesia may not know where they are or be able to seek medical care. If someone you know has symptoms of amnesia, help the person get medical attention.

Causes

Typical memory function involves many parts of the brain. Any disease or injury that affects the brain can affect memory.

Amnesia can result from damage to brain structures that form the limbic system, which controls emotions and memories. They include the thalamus found deep within the center of the brain. They also include the hippocampal formations found within the temporal lobes of the brain.

Amnesia caused by brain injury or damage is known as neurological amnesia. Possible causes of neurological amnesia include:

• Stroke.
• Brain inflammation, which may be due to an infection with a virus such as herpes simplex virus. Or inflammation may be a result of an autoimmune reaction to cancer somewhere in the body. It also may be due to an autoimmune reaction in the absence of cancer.
• Not enough oxygen in the brain. This may happen as a result of a heart attack, respiratory distress or carbon monoxide poisoning.
• Long-term alcohol misuse that leads to too little vitamin B-1, known as thiamin, in the body. When this happens, it's called Wernicke-Korsakoff syndrome.
• Tumors in areas of the brain that control memory.
• Alzheimer's disease and other diseases that involve the degeneration of nerve tissue.
• Seizures.
• Certain medicines such as benzodiazepines or others 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 don't cause lasting amnesia, but more-severe head injuries may cause permanent amnesia.

Another rare type of amnesia, called dissociative amnesia, stems from emotional shock or trauma. It can result from being the victim of a violent crime or experiencing other trauma. In this disorder, people may lose personal memories and information about their lives. The memory loss is usually brief.

Risk factors

The chance of developing amnesia might increase if you've experienced:

• Brain surgery, head injury or trauma.
• Stroke.
• Alcohol abuse.
• Seizures.

Complications

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 be supervised or need to live in a care facility.

Prevention

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:

• Don't drink large amounts of alcohol.
• Wear a helmet when bicycling and a seat belt when driving.
• Treat infections quickly so that they don't have a chance to spread to the brain.
• Get immediate medical treatment if you have symptoms that suggest a stroke or brain aneurysm. Those symptoms include a severe headache, feeling numb on one side of the body or not being able to move one side of the body.

Diagnosis

A comprehensive evaluation is needed to diagnose amnesia. It can rule out other possible causes of memory loss such as Alzheimer's disease, other forms of dementia, depression or a brain tumor.

Medical history

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 usually provides information.

Your health care provider may ask you several questions to help understand the memory loss. Issues that might be addressed include:

• The type of memory loss and whether it's recent or long term.
• When the memory problems started and how they progressed.
• Factors that triggered memory problems, such as a head injury, stroke or surgery.
• Family history, especially of neurological disease.
• Drug and alcohol use.
• Other symptoms such as confusion, language problems, personality changes or not being able to perform self care.
• History of seizures, headaches, depression or cancer.

Physical exam

The physical exam may include a neurological exam to check reflexes, sensory function and balance.

Cognitive tests

The exam typically includes tests related to thinking, judgment, and recent and long-term memory. You'll be asked about your knowledge of general information — such as the name of the current president — as well as personal information and past events. You may be asked to repeat a list of words.

The memory evaluation can help determine the extent of memory loss and provide insights about what kind of help you may need.

Diagnostic tests

Your health care provider also may order:

• Imaging tests — including an MRI and CT scan — to check for brain damage or changes such as shrinkage.
• Blood tests to check for infection, nutritional deficiencies or other issues.
• An electroencephalogram (EEG) to check for the presence of seizure activity.

Treatment

Treatment for amnesia focuses on strategies to help make up for the memory problem. It's also important to address underlying diseases causing the amnesia.

Occupational therapy

You may work with an occupational therapist to learn new information and replace what was lost. Or you may use intact memories as a basis for taking in new information.

Memory training also may include strategies for organizing information so that it's easier to remember and for better understanding when talking to others.

Technological assistance

Many people with amnesia find it helpful to use smart technology, such as a smartphone or a hand-held tablet. With some training and practice, even people with severe amnesia can use electronic organizers to help with day-to-day tasks. For example, smartphones can be programmed to remind them about important events or to take medicines.

Low-tech memory aids include notebooks, wall calendars, pill minders, and photographs of people and places.

Medications or supplements

No medicines are currently available for treating most types of amnesia.

If Wernicke-Korsakoff syndrome is the cause of the amnesia, treatment can help prevent further damage. But most people won't recover all of their lost memory. Treatment includes replacing thiamin in the body, providing proper nutrition and not drinking alcohol.

If Alzheimer's disease is the cause of the amnesia, treatment with medicines called cholinesterase inhibitors can help with symptoms.

Research may one day lead to new treatments for memory disorders. But the complexity of the brain processes involved makes it unlikely that a single medicine will be able to resolve memory problems.

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. They may be able to provide advice or tips on living with amnesia. Ask your health care provider to recommend a support group in your area for people with amnesia and their loved ones.

If an underlying cause for the amnesia is identified, there are national organizations that can provide additional information and support. Examples include:

• Alzheimer's Association, 800-272-3900 (toll-free).
• Brain Injury Association of America, 800-444-6443 (toll-free).

Preparing for your appointment

You're likely to start by seeing your primary care provider. However, you may then be referred to a specialist in disorders of the brain and nervous system, also called a neurologist.

It's a good idea to arrive at your appointment well prepared. Here's some information to help you get ready and to know what to expect.

What you can do

• Write down any unusual symptoms as you experience them, including any that may seem unrelated to the reason for which you scheduled the appointment.
• Write down key personal information, including any major stresses or recent life changes. Ask family members or friends to help you ensure the list is complete.
• Make a list of all medicines, vitamins or supplements you're taking.
• Ask a family member or friend to come with you. Even in the best circumstances, it can be difficult to remember all of the information provided to you during an appointment. A friend or family member can help you remember everything that was said.
• Bring a notepad and pen or pencil to jot down the points you want to be sure to remember later.
• Write down questions to ask your health care provider.

Preparing a list of questions can help you make the most of your time with your provider, as well as ensure that you cover everything you want to ask. For amnesia, some basic questions to ask include:

• What's the most likely cause of my symptoms?
• Are there other possible causes for my symptoms?
• What kinds of tests do I need? Do these tests require any special preparation?
• Will my memory ever come back?
• What treatments are available, and which do you recommend?
• I have other health conditions. How can I best manage them together?
• Do I need to restrict any activities?
• Are there any brochures or other printed material that I can take home? What websites do you recommend?

In addition to the questions that you've prepared, don't hesitate to ask questions during your appointment if you don't understand something.

What to expect from your doctor

Your health care provider is likely to ask you a number of questions, including:

• When did you first notice your memory loss?
• Did you experience any other symptoms at that time?
• Were you involved in any trauma? For example, a car accident, violent collision in sports or an assault?
• Did an illness or another event seem to trigger the memory loss?
• Does anything help improve your memory?
• What, if anything, appears to make the memory loss worse?
• Do the memory problems come and go or are they constant?
• Has the memory loss stayed the same or is it getting worse?
• Did the memory loss come on suddenly or gradually?