Are there early indicators of CTE in the brains of epilepsy patients?

Written by Roisin Conneely

A pilot study from the Mayo Clinic in Rochester (MN, USA) presents a possible link between the symptoms of chronic traumatic encephalopathy (CTE) and epilepsy.
Previous research has highlighted the presence of CTE symptoms in the brains of older epilepsy sufferers, but the team at Rochester wanted to determine if similar patterns could be observed in younger patients.

Study author Gregory Cascino (Mayo Clinic) explained: “Previous studies have found signs of CTE in up to a quarter or even a third of older people with epilepsy, so our aim was to determine if such signs could be found in the brains of younger people with epilepsy.”

The researchers examined microscopic sections of brain tissue from individuals living with epilepsy. The study is limited by the small sample size, with only ten participants who had each been living with epilepsy for an average of 24 years. All participants had previously undergone resective surgery, at an average age of 33. Eight had reported head injury, but these were unlikely to be severely damaging as none had required medical treatment.

Results demonstrated potential symptoms of CTE in only one of the individuals examinedbrain lesions as a result of tau aggregation. However, Cascino claims the other participants may go on to develop the condition in future: “This lack of tau in the brains of our study participants does not mean it’s not possible for them to develop CTE at a later age, but it appears that signs of the disease may not be obvious in most people before they are 50 years old.”

Tau aggregation is not exclusive to CTE; hence its presence in the brain of an epilepsy patient is not conclusive evidence for a link between the two conditions. Furthermore, the suggestion that this symptom is due to CTE caused by seizure-related head trauma is weakened by the fact that none of the patients had a history of repeated serious head injuries due to their seizures.

Whilst an interesting preliminary trial, owing to the sample size limitations, this study shows no strong evidence for a link between early signs of CTE and epilepsy. Results may also have been influenced by the fact that the majority of the cohort had undergone brain resection surgery. Future research to examine larger cohorts of young epilepsy sufferers over longer time periods is essential to determine any potential association.