Types of Memory Loss – Amnesia Definitions

Amnesia is the common medical term used to describe memory loss. There are three primary types of amnesia:

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Retrograde Amnesia is the loss of ability to recall episodic memories and many times semantic memories that happened before a brain injury occurred.

Retrograde amnesia tends be strongest for memories that happened just before the brain injury event. For example, a person who sustains a serious concussion during an automobile accident may not remember anything about his or her life for several days prior to (and including) the accident.


Anterograde Amnesia is the loss of ability to form new episodic memories and many times semantic memories after a brain injury occurs (this also includes the onset of neurological disorders such as Alzheimer’s disease).

Anterograde amnesia significantly and negatively impacts a person’s quality of life. The inability to form any new episodic memories renders a person to live in a perpetual “now” state, where new events are never remembered. This condition can also create safety issues — not remembering that dinner preparation was started on the stove has led to numerous house fires among people with symptoms of Alzheimer’s disease.

Concerned about the possibility of memory loss symptoms in someone close to you? Use the Memory Loss Checklist, a free tool for family, friends, and caregivers.

Global Amnesia

Global Amnesia is typically a temporary state, and is generally known as transient global amnesia (TGA). TGA tends to act as a combination of recent retrograde amnesia (loss of recall for recent events) and anterograde amnesia.

The triggers that can cause TGA seem to cluster around very stressful emotional events and extreme physical exertion. Another possible cause is a transient ischemic stroke. TGA is more prevalent in older adults (age 50+).

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