A huge part of who we are is our memories. If amnesia takes your past from you, are you really the same person? This is part of what I wanted to explore in "Blank Slate Kate". To do that, of course, I needed to learn about amnesia.
There are two basic kinds of amnesia. In 'anterograde amnesia', you can't remember things going forward after whatever event caused the amnesia because those things are no longer able to be transferred into your long-term memory. For example, you might not remember what you had for breakfast today, but you would remember events that happened in your past before the amnesia began.
My book focuses on 'retrograde amnesia', what most people think of when they hear 'amnesia', in which you forget your past. The memories may actually still be stored (which is why amnesia sufferers are often shown pictures and people from their past in the hopes those things will trigger the memories) but they can no longer be accessed.
Our brains are amazingly complex, and it's not always clear precisely what caused a particular person's amnesia. The most common causes I found in my research, though, were:
I found several cases of people being struck in the head during a car accident or even by a soccer ball and losing access to their memories for some period of time. Usually these people do recover within a few months as the brain heals, although often without the memories of the incident that caused the amnesia, but there are exceptions. Scott Bolzan (http://thebolzans.com/) slipped and fell in a bathroom and lost all of the memories of his life save for a few fragments of his childhood. Benjaman Kyle (http://en.wikipedia.org/wiki/
Electroconvulsive therapy (ECT)
This controversial treatment is used for cases of extreme depression or mania. Electrodes are applied to the scalp of a patient under general anaesthetic then enough electricity is sent through the skull to light a light bulb. The current lasts only a fraction of a second. The patient awakens from the anaesthetic confused and with no memory of events around the treatment but with no damage to long-term memories.
At least, that's what's supposed to happen. Throughout my work on "Blank Slate Kate" I was haunted by the stories I read, especially the one about the 55-year-old woman who lost thirty years of her life, including all memories of her children and her marriage to her now-late husband, to ECT. Even eleven years after the treatment, she had regained none of those memories. As if that weren't bad enough, she'd also lost all memories of the career for which she'd trained (psychiatric nursing, ironically) and could no longer work. She did win a judgment against the hospital, but what kind of money would be enough to compensate you for thirty years of your life? ($631,000 is what she won. I'm quite sure she'd rather have her career and memories.)
Alcohol or drug abuse
Taken in sufficient quantities, both alcohol and various drugs can cause tremendous brain damage in all areas, and of course memory can be affected as well. Both memory storage and retrieval can be interfered with by these substances, the precise kind and degree of damage depending on what substance and how much of it. The "I blacked out last night" drinking binge is an example of this kind of amnesia. A dramatic and traumatic event Soldiers who've seen particularly horrific things, victims of child abuse, and survivors of terrorist acts often can't recall the events around the incident. Sometimes the amnesia is specific to that event and sometimes all memories are affected. Many people have experienced this on a smaller scale. Have you ever been involved in a car accident or a robbery and not been able to remember what happened afterward? I once tripped over a sidewalk and had a spectacular fall during a training run (which I immortalized in "Seven Exes Are Eight Too Many" - might as well use my disasters for my books!) and I can clearly see the dog of the man who stopped to help me up but in my memory the man's face is utterly blank other than his sunglasses. I'm quite sure he had features but even later that same day I couldn't recall anything about him. Essentially, my brain was focused on other things ("Are we okay?" "Anything hurt?") and didn't bother to record the details of my helper.
Treating amnesia of course depends on why the memories were lost in the first place. If drugs or alcohol are the cause, then removing those might eventually let the brain recover enough that the memories are restored. Psychotherapy can help, especially in cases brought on by a traumatic event, and so can showing patients people and things from their past to aid in recall. Naturally, if the memories were not stored at all, then there can be no recovery.
If the amnesia can be completely or partially overcome, it's usually the case that the older memories come back first and then the more recent ones. My research didn't entirely reveal the reason for this, although I suspect it's about how firmly recorded a memory is and how many times you've recalled and thought about it. Your newer memories haven't been encoded as deeply because they're still new and you haven't thought about them as much.
Entire careers are built around studying amnesia and memory, and I've definitely simplified things both here and in "Blank Slate Kate". But I've done my best not to be inaccurate in my science and I hope I've succeeded. I also hope that you've enjoyed this post and that if you don't already have my free-to-download "Life, Love, and a Polar Bear Tattoo" (http://www.heatherwardell.
Thanks to Kaley for letting me share my research with you! And if you have any comments or questions about amnesia (which I'll do my best to answer although I'm not a doctor!) or anything else, feel free to post them!