Brain Injury and PTSD: Adventures in Brain

Continuing with things I needed to understand about my brain:

For previous BI and PTSD posts look under the category to the right.

• BI: Diffuse Brain Injuries – these aren’t often talked about, but they seem to be fairly common, if less straightforward than focal brain injuries.

• BI:Everything is Information – Everything we sense (see, hear, taste and feel to put it simply) is information that must be interpreted in the brain, and this can go wrong at a number of stages. The going wrong can be caused by both mental illness and brain damage.

• PTSD: Wired for Survival – there are plenty of non-survival things going on in the brain (feeling confused, making puns, happy memories) but taking precedence is a need to survive.

 

Diffuse Brain Injury

A focal brain injury is localized to one area, a diffuse BI is spread over lots of areas, although the damage may be smaller and less intense in those areas. (Wikipedia page: https://en.wikipedia.org/wiki/Brain_injury )

I had a diffuse BI, which is why I had trouble with so many different aspects of functioning: memory, processing, movement, balance, sense of smell and so on. Because the damage did not wipe out any of those areas completely (as it might in a focal BI) I could be fine some of the time, but the more I did, the more my ability would disappear.

This made it confusing for other people (and me!) to understand what was actually wrong.

Everything is Information

I mentioned this briefly in a previous blog, but in order to understand BI, I think it needs more attention.

Images we see, sounds we hear, even physical sensations and smells, are all types of information that must be processed. This takes both energy and a number of different cognitive tools.

The process: Information enters the brain through an organ (eg eyes, ears)  and then bounces around the brain at great speed using existing information stored in the brain to interpret the new data. New connections are made and memories are formed on the basis that the brain thinks they might come in useful, a lot of information is discarded. The decisions for how the information is interpreted and what new memories are made, is made by routines (like computer programs) usually written in childhood and kept throughout adult life.

For example when we watch TV (I’m going to use Community as an example), our brains are very busy. These are some (but not all) of the processes that are happening. We are utterly unaware that most of them are happening:

• Reading facial expressions – using memory to to decide what the expressions mean, based on experience from childhood of what those expressions meant in the past.
• Remembering who characters are – using recent memory and facial recognition to know who they are  (eg that’s Jeff, he’s a lawyer), but also older memories of how we feel about people like that (he’s vain, I find this silly).
• Understanding language – using memory to know what words and expressions mean.
• Understanding the emotional intent behind speech – the tone, pitch and even speed of speech, indicates this.
• Interpreting jokes – using all sorts of memory, some linked to the programs itself, some to lifelong memories.
• Forming new memories –  about characters and situations that will be useful when watching the next episode.
• Forming new opinions about life – making associations between people and behaviour, between actions and consequences.
• Predicting – what might be about to happen based on previous experience (there’s Chang, he’s about to cause trouble).

With a BI, some or all of the processes can be damaged – either they don’t happen at all, they happen slowly or they happen wrongly. With a diffuse BI these abilities can change by the minute.

Sometimes I could watch a TV program for an hour and more or less understand and enjoy all of it. Sometimes I didn’t really get plot or even speech, but would enjoy watching the facial expressions (Jeeves and Wooster were perfect for this, they would keep me entertained for hours). Sometimes I couldn’t open my eyes, because trying to process what I saw hurt too much – this pain is difficult to explain. The sensation was a little like trying to do complicated arithmetic in your head, in a noisy room. It was a pain of extreme struggle and frustration which would quickly intensify into migraines, muscle pain etc.

As can be seen in the process above, memory is the way all this information holds together. There are many different types of memory that are stored in different parts of the brain (this website has a nice neat diagram showing the different types). It is possible to completely lose one type of memory, or to partially lose lots of them. Access to these memories can also be slowed down to varying degrees.

The way PTSD affects our processing of information is slightly different. Whereas BI slows down, stops or corrupts certain processes, PTSD tends to distort them through a filter of extreme emotion. Because PTSD involves emotions all turned up to 11, information that should be fairly straightforward (eg there is a dog) becomes a warning or a tragedy (that dog is about to attack me! or that dog is sad, it’s been abandoned, oh my God I have to save it!).

When PTSD and BI come together it can get truly ridiculous, because the faulty information caused by the BI then gets further distorted by the PTSD.

For example, once I was walking down a street and getting tired doing so, therefore my ability to process images started to fail. I saw a crisp packet move at the side of the road, couldn’t process what it was, so the PTSD filter came up with It’s an alien! It’s about to attack! And I was genuinely scared. It was a few moments before my memory kicked in with the information that I didn’t believe in aliens and that it was clearly a crisp packet.

Wired for Survival

PTSD is what happens when the brain believes we are in constant mortal danger. The symptoms are its way of dealing with that as it puts us in a to a physical state where we are ready for fight or flight. Due to a genuinely dangerous event, the brain seems to get locked in that state of extreme panic.

There doesn’t seem to be any logic as to why that particular experience affects the brain that way – like most people, I’ve had plenty of near-death experiences in my life, but this is the one that changed how my brain functioned.

These are some signs that the brain is locked:

(Note: All of these can be experienced when a person is stressed, but then when the stress passes, so do the symptoms. With PTSD, the symptoms are at full pelt and they don’t stop. A frustrating mismatch between our brains and modern life is that most modern stresses require clear thinking, but little actual danger. However, our brains assume all stress comes from physical threat and that thinking is irrelevant in such situations.)

• Hypervigilance – paying too much attention to sounds. This is our brains trying to listen out for danger. It is the reason we get more annoyed by noise when we are stressed and trying to concentrate, because under stress our brains think we are in danger and so are trying to listen for any evidence of that.
• Not sleeping – deep sleep is never a good idea when there is danger.
  
• Physical symptoms of stress – tight muscles, gritting teeth, restlessness, these are all signs that the body is ready to fight or flee.
• Over interpreting situations – looking for any sign that something might have gone wrong and then fretting about it.
• Struggling to eat – you brain doesn’t want you eating because it is difficult to fight or flee if you’ve just had a big meal.

Knowing that this is what’s happening doesn’t make the symptoms go away, but it does at least give an awareness that our understanding of the world is distorted: that we have no reason to be afraid, that people around us aren’t threatening or dangerous.

One knock on effect of this constant level of threat is exhaustion. When emotions are always set to 11, the body is working too hard all the time, without any proper rest.

People talk quite a lot about the dramatic symptoms of PTSD (flashbacks and panic attacks) but the exhaustion was most debilitating effect for me. It was so complete that it felt supernatural – as if all my limbs had been injected with lead and my mind was filled with fog.

Next BI and PTSD blog: The Basics of Caring for Yourself with BI and PTSD