Memory Challenges: How Chronic Pain Shrinks the Hippocampus
Have chronic pain and noticed at times your brain seems to have changed into candy floss?
And at times, it seems as if, the candy floss is melting - and getting worse as time goes by?
Well, you're not wrong, as chronic, or persistent pain has been shown to have a negative affect on your brain. More precisely a part of your brain named the 'hippocampus'. The most worrying aspect of this is our hippocampus is an important part of the brain for learning and memory.
"Therefore our hippocampus is an important part of our brains that we really need to protect."
Constant or Chronic Pain has Implications for Learning and Memory
Talking with clients they've often mentioned mental challenges at work.
Ø Where it can take longer than usual to learn new skills
Ø Difficult to adapt to changes in work,
Ø Left them feeling inadequate.
This can also leave patients confused as it can be a recent change, together with feeling exhausted, as work just seems 'harder these days'.
A Memory Sparked by a Podcast
A recent podcast about the detriment of ultra-processed foods on the hippocampus prompted one of my own memories - a comment left by a patient on the Chronic Pain Australia Website.
Strange, how a piece of research, or in this case a podcast about a worrying change in our brains, a decrease in the size of the hippocampus, triggered one of my own memories from 2016.
In 2016, I wanted to be involved in Chronic Pain Week, being the owner of a Pain Clinic in Perth, Western Australia. At that time there was little publicity around chronic pain and I was planning to host an event during pain week.
Unfortunately, as a naturopath I couldn't take part, nor could I become a member of their website. Unfortunate!
At that time I read an extensive comment someone had made on the Chronic Pain Australia website, effectively a cry for help from a man who'd had chronic pain for many years. This was an example of chronic pain affecting a man's memory, let's call him George, and his general cognition that became a problem that impacted his everyday functions.
He Couldn't Understand Why No Doctors Were Listening
"Why is no one listening to me when I try to describe what is happening to my brain. This chronic pain is impacting on my memory".
"My cognition is failing. Recalling events is difficult. I cannot remember facts or hold onto new information or recall conversations."
"Not a single doctor or specialist is listening to me - I know it's related to my pain - nowhere and no one is acknowledging the effect of chronic pain on my brain".
Chronic Pain Patient Not Being Heard
This all sounds very sad, particularly, saying he's 'not being heard'. However, I do agree that perhaps memory and learning are not considered as often, or at all, as physiotherapy, medications and other chronic pain management ideas.
Research: Does Chronic Pain Impact Brain and Memory?
Sometimes when I put 'pen to paper' or fingers to keyboard I'm mostly sharing my thoughts, ideas and experience but today is all about research and it's very worrying to me and should be to you.
How is our brain particularly, the learning and memory done by the hippocampus, affected by chronic pain and lifestyle?
Brain Research Examining the Health of the Hippocampus
To help our understanding and begin to solve any problem, like "our brains turning into candy floss," we need to know -
Ø What the problem is - what is happening to our hippocampus?
Ø What causes a decrease in the size of the hippocampus?
Ø How this affects our learning?
Ø What are the impacts on our memory?
Ø What could be the long-term implications?
Our brain is constantly undergoing something called neuroplasticity - plasticity meaning that it can and does change. Nerve cells or neurons in the brain can get trimmed and pruned with inactivity. You may have heard the expression "use it or lose it" rather reflective of what may happen in our brain, our neural network.
The work done by Mutso (2012) and colleagues has demonstrated a decrease in the size of hippocampus and suggested that there are also changes in its function or what the hippocampus actually does for us within our brain. This first piece of research was to compare the size of the hippocampus or hippocampal volume in groups of patients with three different chronic pain conditions.
Ø Chronic back pain (CBP)
Ø Chronic regional pain syndrome (CRPS)
Ø Osteoarthritis (OA)
Ø A control group of people without pain
Chronic Pain Conditions Have Smaller Hippocampus Volume
Diagram from: Mutso, Amelia A., et al. "Abnormalities in hippocampus functioning with persistent pain.
The diagram above shows brain changes. Compared to the normal black bar, you can see a reduction in the volume of the hippocampus for three pain conditions. The amount of decrease from normal varies between types of chronic pain conditions.
Mutso's investigation and measurements shown in the diagram above make it very clear there is a reduction in the hippocampal volume, or decrease in the size of the hippocampus.
"Reduction in hippocampal volume we see in chronic pain patients, and these abnormalities may underline learning and emotional deficits commonly observed in such patients" pg1.
George was Right - His Brain was in Trouble!
Although the type of chronic pain suffered by George, the man at the beginning of this article is unknown, this research and the diagram above is evidence that he is right and his problems with memory, cognition and learning are valid and need to be acknowledged.
One further point worth mentioning is the hippocampus is involved in giving context to our learning. I remember as a maths teacher the challenge was to have an emotional link, or for the pupils to have an emotional link so they could remember mathematical facts. I mostly failed on this challenge!
Another finding was the disturbance in the nerve connections and neural functioning of the hippocampus may cause negative conditioned learning from the continual experience of pain and understandably negative emotions (note the anger of George above).
What I'm saying here is that we get into a place, or way of being, that we experience every day and have emotions connected with that experience. This can put us in a continuous roundabout or loop.
That loop illustrates we are in pain, constantly, and we have emotions connected with that pain, constantly, therefore we are continually learning to be in pain. Hence the "stuckness" that can happen to some chronic pain patients.
Susceptibility to Persistent Pain due to Past Trauma and Negative Experiences
As some of my regular readers will note I do believe what has happened to us in the past can impact whether acute pain can become chronic pain. So, past trauma and pain experiences I believe can make us more likely to develop chronic pain, could this negative conditioning be involved in this process?
".... the role of the hippocampus to actively encode a range of pain related memories" (Apkarien, 2008)
This idea is discussed more in my article 'What causes pain - Life can? Primarily, the story is about the challenges faced by a single dad doing his very best to raise his children after losing his wife in childbirth.
I plan to further explore/explain this connection in another article, soon. But for now I'll just say that it could help explain the "complete stuckness" of some patients with intractable chronic pain. Patients unable to make changes regardless of treatments, self-help techniques and endless advice and suggestions from a wide range of chronic pain practitioners - a very difficult situation for both patients and doctors.
Returning to the research and diagram above, we can see a difference in the results for different chronic pain conditions. The researchers suggested the more extensive decrease in the size of the hippoccampus for chronic back pain (CBP) and chronic regional pain syndrome (CRPS) could be due to the involvement of neuropathic or nerve pain. In contrast to the patients with osteoarthritis (OA) who have a more inflammatory condition.
"Targetting the reversal of these systematic changes in chronic pain could improve both patient quality of life and actual pain behaviour."
Make Changes Today - Use Natural Pain Solutions
Brain Changes as Acute Back Pain Becomes Chronic Back Pain
I realise this article may be getting technical but stay with me. One other important piece of research also demonstrates negative changes to hippocampal functioning - how the hippocampus connects and relates to other brain areas - occur as patients with acute or short term back pain who fail to recover and move into more long-term back pain.
This research suggested two important possible connections. I say connections, as more research is needed in this area.
Firstly persistent pain may not just be about the size, or volume of the hippocampus. Think about this effective shrinking like the ivy Charlie is cutting in the garden, but also how the hippocampus functions. Or the ivy regrows.
Imagine what happens to a tree pruned at the wrong time. Either crazy growth if pruned too late or new growth killed if exposed to late winter frosts. Both of these effects would have consequences for the future growth and health of the tree.
Secondly, possible brain changes between the hippocampus and other brain areas that underlie learning and emotional abnormalities could have a 'chicken or egg' situation with the possible brain changes making chronic pain worse or chronic pain getting worse prompts more brain changes.
"Complicated, I know, but as you know,
Chronic Pain is Complicated"
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Conclusion - The Brain, Hippocampus and Chronic Pain
Our brain health is often completely neglected in chronic pain treatment. Psychological treatment can be offered but as I’ve shown here the effect of memory recall and learning new information is ignored. These memory and thinking problems weren't covered in my postgraduate training course.
When I asked about cognition and memory (remember the comments of George and my other clients) the only response was the discussion about catastrophising and being fearful and I was pointed to forms more connected to depression and anxiety.
What I write about in this article is the largely ignored problems of being able to function in daily life with a brain that is just not performing as it was before chronic pain developed. This is also regardless of age.
It needs to be remembered when we forget, or recall fails more often than we’re used to it’s very scary. Am I going crazy? Am I getting dementia? Reassurance that our chronic pain be affecting our brain, is worrying but at the same time we have a reason for the changes we’ve experienced.
To end on a brighter note, I hope to continue with more blogs about the brain, its ability to change itself, for good and for bad via neuroplasticity. These will include self-help ideas and changes you can make to help not only your brain but your chronic pain.
In the meantime, try out some self-help techniques - here
I'll be back with you soon!
Chronic Pain Australia
Apkarien AV. Pain perception in relation to emotional learning. Curr Opin Neuroboil. 2008
Mutso, Amelia A., et al. "Abnormalities in hippocampus functioning with persistent pain."
Journal of Neuroscience 32.17 (2012): 5747-5756.
Mutso, Amelia A., et al. "Reoganization in hippocampal functional connectivity with transition to chronic back pain." Journal of neurolophysiology 111.5 (2014): 1065-1076.
Want to find simple effective ways to reduce your chronic pain without increasing your stress and overwhelm? This is where I can help! Ideas can be found in the articles on my website. You can sign-up to regular updates or spend time using some of the collection of self-help techniques. After over 20 years of having my own pain clinics pain clinics I started natural pain solutions to reach more people, rather than one person at a time. Therefore when I completed my postgraduate pain management studies I wanted to spread the word about holistic self-help techniques that people can use at home. Learn more about me here.