Amnesia is a term that most people recognize as meaning a loss of memory. Memory loss is a big factor with this condition, and there are various reasons as to why it occurs. The common link in all amnesia cases is a loss of brain cells.
Amnesia frequently occurs due to a head injury in which the brain is damaged. A severe blow to the head can be enough to cause the condition. If a person suffers head injuries while involved in a car crash, amnesia may result. Such trauma may result in brain damage and loss of brain cells, eventually leading to memory loss. The degree of memory loss is usually in proportion to the severity of the blow to the head.
Deterioration of the brain cells due to infections of the brain can also result in amnesia. Infections such as herpes and encephalitis cause the loss of brain cells. Diseases that cause dementia, such as Alzheimer’s, can also result in amnesia and memory loss.
Another medical cause of amnesia is a link to alcohol and drug abuse. Wernike-Korsakoff's psychosis is a form of memory loss caused by the prolonged abuse of alcohol. The condition worsens if the abuse is extended and can be accompanied by other problems, such as disorientated movements. There may also be loss of feeling to the body’s extremities.
Amnesia can often be set off by a traumatic incident. Known as hysterical amnesia, it is the brain's way of coping with the trauma. The memory may return within a few days, but it may be incomplete.
The extent and length of memory loss depends on the type of amnesia and the cause of it. Anterograde amnesia sufferers are unable to recall any new information. Short-term memory is erased, as are any recent incidents after brain trauma. However, any events before the trauma will be recalled without problem.
The opposite of anterograde is retrograde amnesia. In this type of amnesia, the sufferer will be able to recall any events after the brain trauma, but none from before. One of the rarest forms of memory loss is transient global amnesia. Sufferers of this disorder have trouble retaining new memories, but also have a slight loss of memory going back only a few hours. This type of memory loss is supposedly temporary and is more common in elderly people suffering from vascular problems.
The main problem with memory loss and brain damage is the loss of brain cells. Because of the integrated network of brain cells, those that are lost cannot be renewed. Psychotherapy, some medicines and hypnosis have often been used to help recall lost memories. The degree of success involved with these methods depends on the individual and the amount of brain damage involved.