What is Amnesia?
Amnesia, also sometimes called amnestic syndrome, is a condition in which the patient experiences memory loss. The condition may have a physical cause, such as an injury, infection, or other trauma that impairs brain function. Amnesia may also stem from a psychological cause, such as a traumatic experience that triggers memory loss.
Depending on their cause, some types of amnesia can be temporary, and the patient will eventually regain lost memories or the ability to create new memories. In other cases, mainly where the amnesia is caused by physical damage to the brain, the memory loss may be permanent.
Amnesia is different from dementia. Dementia patients often experience memory loss, but they also suffer from other cognitive problems that are usually not present in cases of amnesia.
The most common symptoms of amnesia include:
- Inability to recall information, events, people, and/or experiences.
- Difficulty recalling past events that occurred before the beginning of the amnesia. This is referred to as retrograde amnesia.
- Difficulty remembering new information or events that occur after the beginning of the amnesia. This is called anterograde amnesia.
- “Memories” of events that didn’t happen or confusion about when actual events occurred.
- General confusion.
Dissociative amnesia caused by traumatic events may take several different forms, including:
- Generalized amnesia. In these very rare cases, patients forget everything about themselves, including their identities and life histories.
- Localized amnesia. In these cases, patients are unable to recall a specific period or a specific event. Often, the area of amnesia coincides with the experience that triggered the memory loss.
- Selective amnesia. In this case, patients forget only some parts of a specific period or event.
- Systematized amnesia. Here, the patient loses a specific type of information, such as memories of a particular person.
- Continuous amnesia. In this case, patients are unable to form new memories.
- Dissociative fugue. These cases involve generalized amnesia, and the patient leaves his or her previous routine after losing memories of his or her identity. In extreme cases, the patient may wander to a new location and start a new life.
What Causes Amnesia?
Amnesia can be caused by any injury, disease, infection, or trauma that damages the parts of the brain that control memory. These parts of the brain include the thalamus, the amygdala, and the hippocampus; amnesia caused by damage to these structures is called neurological amnesia.
Some potential causes of neurological amnesia include:
- Heart attack
- Brain tumors
- Alcohol abuse
- Carbon monoxide poisoning
- Head injury or concussion
- Brain surgery
Some common triggers for dissociative amnesia include:
- Physical abuse
- Sexual abuse and rape
- Violent crime
- Death of a loved one
- Financial stress
- Interpersonal conflict
Amnesia can occur when someone experiences one or more of these triggers directly, or it may happen even to witnesses of traumatic events.
Is Amnesia Hereditary?
Most types of amnesia, both neurological and dissociative, are caused by injury, disease, or external factors. Because the memory loss stems from some external event acting upon the brain’s memory centers, it would seem there is no obvious link between family history and the risk of developing amnesia. However, there is evidence that some people may inherit a tendency to develop dissociative amnesia when exposed to traumatic experiences.
Researchers have identified a particular gene variation that makes people more susceptible to post-traumatic stress disorder (PTSD) or depression after experiencing a traumatic event. The results of one study also suggested the gene may increase the risk of trauma-associated memory loss, as well.
How is Amnesia Detected?
Many of the causes of amnesia result in sudden memory loss, and there are no recognizable signs that precede the memory problems. However, the underlying cause may be a disease, injury, or event that can lead to long-term brain damage or even death, so early signs of these problems shouldn’t be ignored.
- An infection anywhere in your body can spread to your brain and cause, among other things, memory loss. Treat all infections promptly.
- A sudden, severe headache may be a sign of a stroke or brain aneurysm. Other symptoms include paralysis or weakness on one side of the body.
- Seizures can also be an early sign of a problem that can lead to memory loss.
Amnesia differs from normal age-related forgetfulness and also from Alzheimer’s Disease and other forms of dementia.
Early signs of dementia include:
- Difficulties with problem-solving, language, speech, and reasoning. These cognition problems usually don’t occur in cases of amnesia.
- Marked changes in behavior or personality. Depending on the cause, these changes can be a part of amnestic syndrome, but in cases of dementia, they become profound over time.
How is Amnesia Diagnosed?
The diagnostic process for amnesia includes an effort to identify or rule out neurological problems that might be causing memory loss.
- Medical history. The doctor will ask questions about the nature of the memory loss, including when it began, whether it has changed over time, and whether other cognitive symptoms have occurred simultaneously. He or she will look for signs of neurological or psychological triggers, as well as a possible family history of related conditions.
- Physical exam. The physical exam will include neurological function tests, including reflexes, balance, strength, vision, and hearing.
- Cognitive exam. This exam will include tests of logic, reasoning, judgment, and short- and long-term memory.
- Laboratory tests. Blood tests will look for signs of infection, vitamin deficiencies, drug abuse, and other blood chemistry abnormalities.
- Electroencephalogram (EEG). This test monitors your brain’s electrical activity and can help to detect abnormalities in brain function.
- Imaging tests. Magnetic resonance imaging (MRI) and computed tomography (CT) scans can detect problems such as brain tumors, bleeding, swelling, and brain damage.
If the problem seems to be dissociative amnesia, the doctor will compare symptoms to the diagnostic requirements for that disorder:
- The memory loss affects the recall of important information and is more severe than typical forgetfulness.
- The memory loss interferes with daily functioning and/or causes significant distress to the patient.
- The memory loss can’t be explained by other neurological or psychiatric disorders.
How is Amnesia Treated?
Treatment for neurological amnesia may include:
- Occupational therapy. The therapy may focus on recovering lost memories, building new memories, and developing strategies for countering ongoing memory loss.
- Dietary supplements. There are currently no drug-based treatments for amnesia, but memory loss associated with alcoholism is sometimes caused by a thiamin deficiency (vitamin B1). In this case, B1 supplements may help.
- Memory aids. Organizers, calendars, photographs, and technological reminder systems can help a sufferer to function.
Treatment for dissociative amnesia can include:
- Psychotherapy. Sessions with a professional therapist can help the sufferer address the traumatic source of the amnesia and learn to cope with its effects.
- Cognitive Behavioral Therapy (CBT). This type of psychotherapy helps the sufferer to develop strategies to counter harmful thoughts and behaviors.
- Hypnosis. Clinical hypnosis aims to help the sufferer, through relaxation techniques, possibly recover lost memories and stop ongoing memory loss.
- Meditation and alternative therapies.
- Medication. Medications may be used to treat depression or anxiety if they are present in conjunction with the amnesia.
How Does Amnesia Progress?
Some types of amnesia can be temporary, and all the sufferer’s memories are eventually restored. A kind of brief amnestic syndrome, called transient global amnesia, often resolves itself within a day or less.
Types of amnesia caused by brain damage, however, are more likely to be permanent. When memory loss is profound and permanent, the sufferer may need long-term care and/or supervision.
Dissociative amnesia can sometimes resolve quickly, and the sufferer can regain lost memories. In other cases, the memory loss may be permanent. The likelihood of a good outcome often depends on whether or not the sufferer can successfully deal with the traumatic circumstances that triggered the amnesia.
How Do I Prevent Amnesia?
There is no known way to prevent the onset of amnesia directly. The best strategy for the prevention of memory loss is to avoid the situations that cause the memory loss:
- Treat infections promptly.
- Follow safety rules when engaging in activities where there is a risk of head injury. Always wear a seat belt while driving or riding in a vehicle.
- Don’t abuse alcohol.
- Be alert to warning signs of a stroke.
Amnesia Caregiver Tips
If your loved one suffers from amnesia, coping with the disorder’s effects can lead to frustration, confusion, and even depression. Keep these tips in mind to best support your loved one and maintain your own mental health.
- Accompany your loved one to all medical appointments. Because of the very nature of amnesia, you might be better equipped than your loved one to answer questions and retain medical advice.
- Provide a safe, secure, stress-free environment where your loved one will have the best chance of recovery.
- Help your loved one with reminder systems, organization, and any other technique that will help with daily functioning during the recovery period.
- Take advantage of other family members, friends, and your community to care for your loved one. Don’t try to take on the entire responsibility for caregiving by yourself.
- Seek out a support group. It can be beneficial to be able to talk to others who are in your situation.
Many people with amnesia also suffer from other brain and mental health-related issues, a condition called co-morbidity. Here are a few of the disorders commonly associated with amnesia:
Amnesia Brain Science
Researchers are working to understand the neurology of amnesia, hoping that a better understanding of why the condition occurs at the cellular level could lead to more effective techniques for treating and reversing memory loss. Some scientists believe that amnesia is caused by cell damage that prevents memories from being stored in the brain. Others believe that memories continue to be stored but that some neurological problem prevents the amnesiac from accessing the stored memories.
Many research projects are aimed at pinpointing the causes of amnesia, including:
- One study has modified memory-storing nerve cells in mice to make the cells sensitive to light. The scientists then used light to try to recall the mice’s memories artificially. The experiment helped scientists understand the difference between memory-formation, memory-storage, and memory recall mechanisms in rodents’ brains.
- Another study focused on how a person’s awareness of the recording of a fact in their memory plays a role in the ability to recall that fact later. The study seemed to show that participants were better able to successfully record a fact when they knew that they were being asked to form a new memory.
Title: Targeted Transcranial Magnetic Stimulation to Improve Hippocampal-dependent Declarative Memory Abilities
Contact: David E. Warren, PhD
University of Nebraska Medical Center
The investigators propose a pilot study of the potential for non-invasive transcranial magnetic stimulation (TMS) to improve memory in healthy adults (young and old) and to treat memory deficits in older adults with amnestic mild cognitive impairment (aMCI). aMCI is a condition that frequently precedes Alzheimer’s disease (AD), and a key symptom of aMCI is clinically significant memory loss (i.e., rapid forgetting) greater than expected for age. The investigators will test whether a form of non-invasive brain stimulation, repetitive transcranial magnetic stimulation (rTMS), can improve memory abilities in healthy young adults, healthy older adults, and older adults with aMCI by retuning memory-related brain networks.
Title: Home-based Brain Stimulation for Memory (MemStim-home)
Principal Investigator: Alvaro Pascual-Leone, Dr.
Hinda and Arthur Marcus Institute for Aging Research
This is a feasibility study, which will include older adult participants (Ps) with memory deficits, together with willing and able administrators (As), to administer tACS to the participants. This study will include 20 older Ps and 20 As to assess the feasibility of deploying home-based tACS in larger clinical trials and prepare for the development and implementation of such trials. The proposed project will systematically examine the feasibility of remote, caregiver-led tACS for older adults vulnerable to memory decline. This study will provide data to support the safety and effectiveness of home-based tACS in this population. It will lead to future research to increase access to tACS as a part of memory decline prevention and treatment for older adults who have more difficulty reaching a clinic for treatment due to disability or who live more remotely.
Title: Dietary Modulation of Neuroinflammation in Age-Related Memory Disorders
Contact: Richard Sloan, PhD
Columbia University Medical Center
New York, NY
Within 25 years, the US population aged 65 and over will double in size to 80 million, bringing with it an epidemic of aging-related cognitive decline, from normal cognitive aging to neurodegenerative disorders, including Alzheimer’s Disease. These conditions impair quality of life and functional status, impose an enormous burden on individuals, their families, the healthcare system, and require elucidation of mechanisms and development of new treatments to prevent or at least slow their progression. The use of plant-based food and drink for health purposes has a long and well-documented history. Cocoa beans contain a substance that has multiple beneficial health effects. In this study, the investigators will test this substance’s impact on brain structures and cognitive outcomes in a 12-week randomized controlled trial of 146 healthy participants, age 50-69, who will receive this cocoa derivative or a placebo. The investigators also will examine the role of inflammation in this relationship. Such a trial has the potential for significant clinical impact.