by DR Y.L.M.
My cousin was recently involved in a car crash. She sustained a head injury and, when she woke up, she had no memory of the crash itself. The doctors tell me this is amnesia. What does amnesia mean?
Amnesia is defined as a profound memory loss that is usually caused by an injury to your brain. There are two main types of amnesia - anterograde and retrograde.
In anterograde amnesia, you cannot remember recent information – such as the events of your crash. Your short term memory goes away, so even when you are lying on the hospital bed, you cannot remember anything that is happening to you after a few moments.
You cannot remember what you had for breakfast after you have eaten it, and you cannot remember who just visited you. When you go home, you cannot hold on to a job any longer because you cannot remember where you put that spreadsheet just moments ago, or what you were even supposed to do with it in the first place.
This type of amnesia is usually caused by damage to the hippocampus, fornix, and mamillary bodies – the areas of your brain that form new memories. But you will remember events from long ago, such as prior to your crash and what you did last week, and most certainly your name.
Wait, this is the famous type of amnesia they like to write about in movies, right? Like The Bourne Identity, where the hero cannot remember his name or who he was?
Yes. But those are very severe cases the movies like to play up! Most retrograde amnesia is not that severe. It is the opposite of anterograde amnesia.
Here, you will be able to remember the events of your crash (or any trauma) clearly, but not the events before it. You usually lose all memory of the events just before the crash, but your long-term memory (such as your name and where you work) is likely to be safe.
This one is usually caused by damage to the areas of your brain used in storing old memories, namely your temporal lobes and hippocampus.
In rare, unfortunate cases, both anterograde and retrograde amnesia can exist in the same patient.
Is a brain injury due to a car crash or blow to your head the only cause of amnesia?
No. Anything that affects your brain can cause amnesia. Physical injury, infections, drugs, alcohol abuse, degeneration due to dementia, strokes affecting the memory areas of your brain, even severe emotional stress, can all lead to some form of memory loss.
What other types of amnesia are there?
The other types are categorised more by their cause than their nature.
Traumatic amnesia, as its name implies, is caused usually by a blow to the head. This one is usually transient. It can be accompanied by a brief loss of consciousness. How long the amnesia lasts is actually dependent on how severe the brain injury is. The more severe, the worse the amnesia is.
Transient global amnesia combines severe anterograde amnesia (inability to form new memories) and milder retrograde amnesia (you still retain most of your past memories, though you can not remember anything that happened in the past few hours).
This one, again as its name implies, is only temporary and is caused by blood vessel disease in the brain. It happens more commonly in older people.
Wernicke-Korsakoff's psychosis is an amnesia caused by prolonged alcohol use. This one tends to get worse and is accompanied by other symptoms such as in-coordination and loss of feeling in the fingers and toes.
Hysterical amnesia is the type caused by a very traumatic emotional event (stress) that you cannot handle, eg watching the murder of a loved one, a violent rape. Your memory usually returns within a few days, though you may never fully remember the events of the trauma itself.
Infantile/childhood amnesia occurs when you cannot recall the memories from your early childhood. It is believed that some of the areas of your brain linked to memory were not fully mature at childhood.
Can amnesia be treated?
Amnesia has to be treated according to its root cause. For example, if your amnesia is caused by brain trauma, recovery or even surgery is the rule.
If your amnesia is caused by alcohol abuse, then by any means, you have to stay away from alcohol. If your amnesia is caused by a severe emotional stress, then psychotherapy and group therapy can help you recover emotionally.
For the amnesia itself, if you are stuck with it, the best you can do is cope. It can be very difficult for someone to cope with anterograde amnesia, but it helps if the sufferer writes down a daily schedule so that he does not forget where he is and what he is supposed to do at that hour.
For retrograde amnesia, it is very difficult to recover lost memories.
More info on AMNESIA here.
by DR Y.L.M.