What types of amnesia are there?
Anterograde amnesia. This form of amnesia follows brain trauma and is characterized by the inability to remember new information. Recent experiences and short-term memory disappear, but victims can recall events prior to the trauma with clarity.
Retrograde amnesia. In some ways, this form of amnesia is the opposite of anterograde amnesia: the victim can recall events that occurred after a trauma, but cannot remember previously familiar information or the events preceding the trauma.
Transient global amnesia. A temporary loss of all memory, but it particularly affects the ability to form new memories (severe anterograde amnesia), with milder loss of past memories (retrograde amnesia) going back a few hours. It is rare and is most common among older persons with vascular disease.
Traumatic amnesia. Traumatic amnesia is caused by brain damage from a hard blow to the head, such as in a car accident. It can lead to anything from a brief loss of consciousness to coma. Traumatic amnesia is often transient, the duration of the amnesia is related to the degree of injury and may give an indication of the prognosis for recovery of other functions.
Wernike-Korsakoff's psychosis. Wernike-Korsakoff's psychosis is memory loss caused by extended alcohol abuse. This tends to be a progressive disorder and is usually accompanied by neurological problems, such as uncoordinated movements and loss of feeling in the fingers and toes.
Hysterical (fugue) amnesia. Hysterical (fugue) amnesia is usually triggered by a traumatic event that the person's mind is unable to properly handle. Usually, the memory slowly or suddenly returns a few days later, although memory of the trauma itself may remain incomplete.
Infantile/childhood amnesia. Infantile/childhood amnesia refers to a person's inability to recall events from early childhood. Some say this type of amnesia could be linked to language development or the fact that some areas of the brain linked to memory were not fully mature.
Posthypnotic amnesia is where events during hypnosis are forgotten, or where past memories are unable to be recalled.