Brain differences associated with epilepsy

Epilepsy is associated with thickness and volume differences in the grey matter of several brain regions, according to new research.

The largest-ever neuroimaging study of people with epilepsy, led by UCL and the Keck School of Medicine of USC in the US, shows that epilepsy involves more widespread physical differences than previously assumed.

The study’s lead author, Professor Sanjay Sisodiya from the UCL Institute of Neurology & Epilepsy Society said: “We found differences in brain matter even in common epilepsies that are often considered to be comparatively benign. While we haven’t yet assessed the impact of these differences, our findings suggest there’s more to epilepsy than we realise, and now we need to do more research to understand the causes of these differences.”

The team found reduced grey matter thickness in parts of the brain’s outer layer (cortex) and reduced volume in subcortical brain regions in all epilepsy groups when compared to the control group. Reduced volume and thickness were associated with longer duration of epilepsy. Notably, people with epilepsy exhibited lower volume in the right thalamus – a region which relays sensory and motor signals, and has previously only been associated with certain epilepsies – and reduced thickness in the motor cortex, which controls the body’s movement.

These patterns were even present among people with idiopathic generalised epilepsies, a type of epilepsy characterised by a lack of any noticeable changes in the brain, such that typically an experienced neuroradiologist would not be able to see anything unusual in their brain scans.

“From our study, we cannot tell whether the structural brain differences are caused by seizures, or perhaps an initial insult to the brain, or other consequences of seizures – nor do we know how this might progress over time. But by identifying these patterns, we are developing a neuroanatomical map showing which brain measures are key for further studies that could improve our understanding and treatment of the epilepsies,” said Professor Sisodiya.

The results are published in Brain.