Surgery may reverse imaging-defined brain age in mesial temporal lobe epilepsy

Surgery for mesial temporal lobe epilepsy correlated with a reduction in imaging-defined brain age, indicating that morphological brain changes related to accelerated aging may be reversible, according to a study published in Neurology.

The findings also highlighted the benefits of resective surgery on overall brain health for patients with refractory focal epilepsy, the researchers noted.

“A machine learning model for estimating chronological age from structural MRI scans has shown promise,” Christophe E. de Bézenac, PhD, from the department of pharmacology and therapeutics in the Institute of Systems, Molecular and Integrative Biology at the University of Liverpool, and the Walton Center NHS Foundation Trust, both in the United Kingdom, and colleagues wrote. “Increased brain-predicted age (relative to actual age) indicates accelerated aging or higher cumulative exposure/sensitivity to pathological brain insults, in contrast to brain resilience. The Brain-Age-Gap-Estimation (BrainAGE) has been used to examine neurodegenerative and psychiatric disorders and the influence of gene interaction, environment and life burden. In epilepsy, increased BrainAGE was observed in patients with refractory focal epilepsy and patients with [temporal lobe epilepsy (TLE)] and inter-ictal psychosis.”

de Bézenac and colleagues collected 3D T1-weighted MRI scans before and after temporal lobe surgery from 48 patients with mesial temporal lobe epilepsy (mTLE) at the University Hospital Bonn, Germany, to estimate brain age using a gaussian processes regression model. After controlling for brain volume change, investigators assessed BrainAGE before and after surgery and compared patients with 37 age- and sex-matched control participants.

Compared with control participants, patients had a preoperative increased BrainAge of 7.97 years (95% CI, 5.26-10.8); however, after surgery, that increase dropped to 2.8 years (95% CI, 0.05-5.78) regardless of whether surgery yielded complete seizure freedom. The researchers also noted a lateralization effect among patients with left mesial temporal lobe epilepsy, who had BrainAge values that were similar to the control group values after surgery.

“Our findings showed that patients with left mTLE were more likely to have normalized BrainAGE after surgery relative to patients with right mTLE, though no difference was found in resection size between left and right surgery,” de Bézenac and colleagues wrote. “This is an additional novel finding and we can only speculate on the reasons why there is a lateralization difference. Surgery aside, it is well demonstrated that patients with left and right mTLE have different distributions of brain abnormalities: Patients with left mTLE are frequently reported to have a more bilateral and widespread distribution of brain alterations relative to patients with right mTLE, as well as a more intense progression of white and grey matter atrophy.”

Further, the possibility that certain morphological brain changes associated with accelerated aging in mesial temporal lobe epilepsy may be reversible aligned with results from other studies, according to the researchers.

“This is consistent with studies that found neuropsychological improvements following surgery and those calling for earlier surgical intervention where medical therapy is ineffective,” de Bézenac and colleagues wrote. “Models of brain-predicted age may provide insight into the treatment and prognosis of epilepsy.”