The Science of MS
Introducing brain atrophy
Let’s talk brain matters
When we talk about multiple sclerosis (MS), we often talk about things like lesions and relapses, but you might have also heard about something called brain atrophy. Brain atrophy is being talked about more and more these days, especially by some MS experts, so what exactly is it? And why are we talking about it?
To answer these questions we need to take a few steps back. MS is a neurological disease that causes damage to the cells in your brain and spinal cord (the central nervous system). So let’s take a really quick look at how the central nervous system (CNS) works, some of the things it does and what leads to the symptoms of MS.
The CNS is the body’s main control centre. Even when you’re chilling out watching TV, your CNS controls your breathing, your temperature and the muscles helping you stay upright. It makes sense of the moving images you’re seeing, the sounds you’re hearing and all while forming new memories too. Pretty exhausting when you think about it, right?
The cells in the CNS making all of this possible are called neurons (sometimes called nerve cells). They form connections and networks along which messages can travel. Neurons are strange looking cells made up of a cell body and a long fibre called an axon, which carries messages. The axon is coated in the fatty substance called myelin that protects the axon and helps signals to travel efficiently.
The cause of MS is still unknown but we do know that the immune system is involved. Our immune system is vital for our survival, protecting us from harmful things. But in MS, the immune system mistakenly sees myelin as a foreign material, and attacks it.
When myelin is damaged, the signals can’t travel as fast. And once the myelin around the nerve is completely destroyed, the signal may become blocked altogether, resulting in a broken connection.
Brain atrophy is something that happens to absolutely everyone, not just if you have MS. In fact, it’s a normal part of ageing. Our brains keep growing until we are in our very late teens and then very slowly start to shrink. This process can also be called brain volume loss, or brain shrinkage. But the damage caused by MS can make this happen a little bit faster.
So why can this happen in MS? Some cells in the brain die as a part of normal aging but in MS there are other processes taking place as well. For example, when myelin is destroyed the axon becomes much more vulnerable to further damage from the immune system. Sometimes resulting in the loss of the whole neuron. The continued loss of neurons and myelin can lead to the brain shrinking faster than normal.
The brain tries to cope with this damage by replacing the myelin and by using other pathways to re-route signals around these broken connections. But as these alternative pathways become damaged and broken themselves due to MS, the brain can no longer compensate.
Because the brain can find ways to compensate for some of this damage, changes to the brain can take place early on in MS, before you start to notice any symptoms.
These early changes in MS, including damage to neurons, brain atrophy and the development of lesions, are important as they have been linked to a number of problems, including long-term disability, problems with walking, vision, sexual function and mental health.
Brain atrophy is a result of damage to the brain in MS and is something to be thinking about when looking after your brain health. If you would like to know more about ways you can keep your brain healthy, take a look at this short guide. A guide for people with multiple sclerosis.
1. De Stefano N, et al. Arch Neurol 2001; 58: 65–70
2. Janardhan V, Bakshi R. Arch Neurol 2000; 57: 1485–1491
3. De Stefano N, et al. J Neurol Neurosurg Psychiatry. 2015; 0: 1-7
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