People rely on memory to do everyday tasks. Damage to the brain or emotional trauma can result in memory loss, also called amnesia. The memory loss may be temporary, as from electroconvulsive therapy, or permanent, as from traumatic brain injury. The National Institutes of Health notes that with severe memory loss, people may confabulate, or create stories, to make up for gaps in their memory.
Retrograde Amnesia
With retrograde amnesia, patients cannot remember events that occurred before the cause of their memory loss. For example, if a person suffers from a head injury, he may not remember what happened leading up to the injury. Rutgers University states that patients do not lose all of their memories with retrograde amnesia. Since brain injury or disease causes the retrograde amnesia, patients do not recover their lost memories. For example, patient H.M., who had surgery on his temporal lobe to stop seizures, had retrograde amnesia that affected his memories from two years before his surgery up until his surgery, according to the Canadian Institutes of Health Research.
Anterograde Amnesia
The most common form of memory loss, anterograde amnesia affects patients' ability to form new memories, according to Rutgers University. Just like in retrograde amnesia, brain damage causes anterograde amnesia. Since this kind of memory loss prevents patients from learning new information, it can affect their ability to keep a job. The Canadian Institutes of Health Research adds that H.M. also had severe anterograde amnesia. As a result, his memories were restricted to those unaffected by retrograde amnesia.
Anterograde amnesia affects both short-term memory and long-term memory. With short-term memory loss, patients cannot remember events that just occurred. For example, if a patient has a conversation, she cannot remember what she was talking about a few seconds later. With long-term memory loss, patients cannot store new memories and cannot recall the memories later in time.
Fugue State
A specific type of memory loss, fugue state affects patients' sense of self. Rutgers University states that patients forget their personal histories. Psychological trauma causes fugue state, unlike physical trauma that causes both retrograde and anterograde amnesia. As a result, psychotherapy treats fugue state, and patients can regain their identities.
