What Is Amnesia?
Amnesia is a form of memory loss. Some people with
amnesia have difficulty forming new memories. Others cannot recall facts and
past experiences. People with amnesia usually retain knowledge of their own
identity, as well as motor skills.
Mild memory loss is a normal part of aging. Significant
loss of existing memories, or the inability to form new memories, could indicate
the presence of an amnestic disorder.
Types of Amnesia
There are multiple types of amnesia:
Retrograde amnesia is when
existing memories are lost. It frequently affects recently formed memories.
Older memories are affected more slowly. Diseases such as dementia cause gradual
Anterograde amnesia is when a
person cannot form new memories. This effect can be temporary, such as in a blackout
caused by too much alcohol. It can also be permanent, such as when a person has
suffered damage to the area of the brain known as the hippocampus (which plays
an important role in forming memories).
Transient Global Amnesia
Transient global amnesia (TGA)
is a poorly understood condition. It is when a person experiences confusion or
agitation that comes and goes repeatedly over the course of several hours. The person
may experience memory loss in the hours before the attack and usually has no
lasting memory of the experience. Scientists think that TGA occurs as the
result of seizure-like activity or of a brief blockage of the blood vessels
supplying the brain.
Causes of Amnesia
A memory’s location in the brain is thought to depend on the
memory’s age (Costandi,
M., 2009). To lose old memories,
a person must experience widespread brain deterioration, such as the
progressive memory loss due to Alzheimer’s disease or other forms of dementia. People
with dementia usually lose more-recent memories first and keep older memories
Anoxia (a depletion of oxygen levels) can also affect the
whole brain, although if it is not severe enough to cause brain damage, the
memory loss it causes can be temporary.
The hippocampus is responsible for forming new narrative memories, retrieving
recently formed memories, and sending these new memories to become associated
with the rest of the brain. Its cells are some of the brain’s most
energy-hungry and fragile. They are most easily disrupted by anoxia, general
anesthetic, toxins, and other threats. While the hippocampus is impaired, a
person will have difficulty forming new memories. Stroke, tumors, and infection
can cause permanent damage to the brain, including permanent memory problems.
If a person suffers damage to the hippocampus in both
halves of the brain, such as from encephalitis, he or she can develop complete
anterograde amnesia, which is the inability to form any new narrative memories.
Concussions commonly disrupt memories of the hours, days,
or weeks before and after the injury.
Short-term alcohol use can cause blackout, a temporary
form of anterograde amnesia. Long-term alcoholism can cause Wernicke-Korsakoff
Syndrome. A person with this condition will have difficulty forming new memories
but may not be aware of the fact.
A person who receives electroconvulsive therapy for
depression or other conditions will usually experience retrograde amnesia of
the weeks or months before their treatment.
Severe trauma or stress can cause dissociative amnesia, in
which the mind rejects thoughts, feelings, or information that the person is
too overwhelmed to handle.
Most people are unable to remember the first three to
five years of life. This common phenomenon is called Infantile or childhood
How Is Amnesia Diagnosed?
Amnesia can be diagnosed by a physician or neural
A person with amnesia will have difficulty recalling
facts, events, places, or specific details, such as that morning’s breakfast or
the name of the current president. They will still retain their motor skills,
such as the ability to walk, as well as fluency in any languages they speak.
How Is Amnesia Treated?
Treatment for amnesia usually consists of treating the
Chemically induced amnesia can be resolved by letting the
person detoxify from the drug. Amnesia from concussion or other mild head
trauma usually resolves over time. Amnesia from severe head injury may not
recede. Improvement is usually seen by six to nine months (Kolb, et. al, 2003).
People with persistent memory loss can get occupational
therapy to learn new information and memory skills to replace the missing or
broken connections. Therapy also teaches techniques for organizing information
to make it easier to retrieve, as well as the use of memory aids.
Preventing Memory Loss
The following healthy life practices may aid in
preventing memory loss:
- Avoid heavy use of alcohol or drugs.
- Use protective headgear when engaging in sports
that are at high risk for causing concussion.
- Keep mentally active throughout life. For
instance, take classes, explore new places, read new books, and play mentally
- Stay physically active throughout life.
- Eat a heart-healthy diet including fruits,
vegetables, whole grains, and low-fat proteins.
- Stay hydrated.