In people with temporal lobe epilepsy (TLE), grey matter – the darker part of the brain that consists of densely packed nerve cell bodies – becomes reduced in particular areas. A recent study, published in the Journal of Clinical Neurology, has now shown that this decrease is more pronounced in people with right-sided TLE than in those with left-sided TLE.The research also suggests that the extent of grey matter ‘volume’ reduction is linked to clinical characteristics such as the duration of the person’s condition and the frequency of their seizures.During the study, the researchers, led by Dr Seung Bong Hong, at Sungkyunkwan University School in South Korea, recruited a total of 60 people with TLE, half left-sided and half right-sided, who had undergone successful epilepsy surgery. They also enrolled 30 age-matched, healthy controls for comparison. The researchers examined the brains of the subjects using magnetic resonance imaging (MRI) and made measurements of their grey matter volume.The results showed a decrease in grey matter in four structures of the brain in people with left TLE compared with controls. Two of the four structures were only affected on one side of the brain, one was affected on both sides and the other was affected only on the right side.In subjects with right-sided TLE, grey matter loss was found to affect more brain structures than in those with left-sided TLE, but a large proportion were affected on both sides of the brain.  This meant that grey matter reduction was more extensive in the right-sided TLE group overall.In people with right-sided TLE, more extensive loss of grey matter was associated with a longer duration of epilepsy, a lower age of onset and more frequent seizures. In those with left-sided TLE, however, it was linked to a lower age of onset and a history of febrile seizures.The results of this study, which correlate epilepsy pathology with clinical outcomes, suggest that the imaging methods used here may be useful in gaining a deeper understanding of the epileptic networks involved in TLE. This will hopefully lead to better management of the condition.As the findings were in people who had responded well to epilepsy surgery for previous two years, this work could also contribute to the complex field of surgical assessment in the future.Author: Dr Özge ÖzkayaClick here for more articles about brain science including genetics.