Differences in brain volume, gray matter thickness tied to epilepsy

New research from the University College of London (UCL) and the Keck School of Medicine at the University of Southern California (USC) found that epilepsy correlates with thickness and volume differences in the gray matter of several areas of the brain.  

According to a release from UCL, the study published Jan. 21 in Brain reveals how different types of epilepsy portray more widespread physical differences than scientists previously thought. The study was conducted by the global ENIGMA-Epilepsy consortium located at USC.  

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

Researchers from UCL and USC collected data from 24 research centers throughout Europe, North and South America, Asia and Australia, according to study methods, and extracted structural brain measures from 2,149 MRI brain scans of people with epilepsy. Additionally, the researchers pooled together 1,727 health controls and were analyzed for common brain patterns while divided into four subgroups to separate identified neurostructural differences. 

According to results, researchers found a commonality in all epilepsy groups: reduced gray matter thickness in the brain's cortex and reduced volume in the subcortical brain regions. Furthermore, the researchers concluded reduced volume and thickness relates to a longer duration of epileptic seizures.

"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," Sisodiya said, according to the press release.

Additionally, these same patterns were found in people with idiopathic generalized epilepsies, which otherwise would not be visible to a neuroradiologist from a typical brain scan. According to the study, researchers noted that the differences between subgroups equate to "differences in underlying biology."

"Some of the differences we found were so subtle they could only be detected due to the large sample size that provided us with very robust, detailed data," said Christopher Whelan, with USC & Royal College of Surgeons in Ireland. "We have identified a common neuroanatomical signature of epilepsy, across multiple epilepsy types. We found that structural changes are present in multiple brain regions, which informs our understanding of epilepsy as a network disorder."