Epilepsy-related brain circuits found in mapped lesions

New brain circuits discovered by mapping epilepsy-related lesions may have clinical implications in predicting epilepsy risk in patients after brain injury, a study found.

“We are learning more and more about where epilepsy comes from in the brain and what brain circuits need to be modulated to treat people with epilepsy,” said Harvard Medical School’s co-author of the study. Frederick Shaper, M.D., lecturer in neurology and scientific lead author, said. Speaking at the Brigham and Women’s Brain Circuit Therapy Center, he said: in the statement.¹ “Using the wiring diagram of the human brain, lesion network mapping allows us to go beyond the location of individual lesions and map their connected brain circuits.”

This case-control study JAMA Neurology.² To the researchers’ knowledge, this study is the first of its kind to investigate the association of lesion connectivity and epilepsy across different lesion etiologies.

Focal epilepsy is known to affect more than 30 million people worldwide, but it remains unclear why some lesions cause epilepsy and others do not. In this study, researchers aimed to better understand whether the location of epilepsy-associated lesions can be mapped to specific brain regions and brain networks.

Researchers used a technique called lesion network mapping to study more than 1,500 patients with brain lesions worldwide, including centers at Brigham and Women’s Hospital in the United States, Massachusetts General Hospital, Boston Children’s Hospital, and Northwestern University. We studied two datasets.

The researchers identified a total of 347 epileptic patients and 1126 epileptic patients in all data sets analyzed from September 2018 to December 2022. In addition, lesions were located in 76 stroke epilepsy patients and 625 stroke patients.

Epilepsy-associated lesions were found in multiple heterogeneous locations across different lobes and vascular regions, but these locations are part of specific brain networks of functional connectivity with the basal ganglia and cerebellum. bottom. These findings were then validated across his four independent cohorts of 772 patients with brain lesions, 271 (35%) of whom had epilepsy.

After validation, researchers found that lesions associated with this brain circuit were associated with increased risk of epilepsy after stroke (odds ratio) [OR]2.82; 95% CI, 2.02–4.10; P. < .001) and across different lesion types (OR, 2.85; 95% CI, 2.23–3.69; P. < .001).

The researchers also analyzed outcomes in 30 patients with drug-resistant epilepsy who received deep brain stimulation (DBS) treatment for seizures. As a result, these patients had improved seizure control (r = 0.63; P. < .001), if the DBS sites were connected to the same brain network identified by lesion mapping.

The researchers focused their studies on brain networks from focal brain lesions because it was unclear whether the results would remain significant across other causes of focal and generalized epilepsy. acknowledges that there are limits to Furthermore, lesion network mapping uses functional connectivity data from healthy patients to estimate the connectivity of lesion locations in the average brain, whereas individuals with brain lesions or epilepsy have functional connectivity. Gender may change and may change over time.

Despite these limitations, the researchers believe the study may help clinicians identify patients at high risk for epilepsy after brain injury and direct them to appropriate treatments such as DBS. there is

“We now have a better understanding of what brain circuits play a role in both the causation and control of epilepsy, which opens up promising opportunities for guiding therapies,” said Professor Shaper. . in the statement.¹ “Future clinical trials are needed to determine whether this circuit can effectively guide brain stimulation therapy for epilepsy and benefit patients.”

References

1. Brigham and Women’s Hospital. A new brain circuit in epilepsy has been elucidated. Yulek Alert! July 3, 2023. Accessed 10 July 2023. https://www.eurekalert.org/news-releases/994221.

2. Schaper FL, Nordberg J, Cohen AL, et al. Mapping lesion-related epilepsy to human brain networks. JAMA Neurology. Published online on July 3, 2023. doi:10.1001/jamaneurol.2023.1988