Brain Scan And EEG Match Linked To Better Outcomes

What was studied

This paper was a systematic review of studies about epilepsy surgery for mesial temporal lobe epilepsy caused by hippocampal sclerosis, also called mesial temporal sclerosis. It looked at which findings before surgery were associated with becoming seizure-free after surgery.

The authors searched major medical databases and included 24 cohort studies published from 2010 to 2025. These studies included people who had different types of surgery, such as anterior temporal lobectomy, selective amygdalohippocampectomy, or stereotactic laser ablation. The review focused on preoperative clinical findings, EEG results, brain imaging, and neuropsychological testing.

What they found

Across the included studies, seizure freedom after surgery was reported in about 50% to 75% of patients. For anterior temporal lobectomy, seizure freedom was about 70% at 1 to 2 years in the studies reviewed.

The preoperative pattern most strongly associated with seizure freedom was multimodal concordance. This means several presurgery tests pointed to the same side and same area as the source of seizures, such as MRI showing visible hippocampal sclerosis, EEG showing seizures starting on one side, and PET showing matching low metabolism in that same area.

Findings on both sides of the brain were consistently associated with poorer seizure outcomes. Some structural measurements, like hippocampal subfield volumes and different hippocampal sclerosis subtypes, appeared to have limited prognostic value.

Limits of the evidence

This was a review of cohort studies, not a randomized trial, so it can show patterns of association but cannot establish that any one presurgery factor causes better or worse outcomes. The included studies likely differed in patient selection, surgery type, follow-up time, and how outcomes were measured, which can affect how consistent the results are.

The abstract does not give detailed information about ages, exact sample sizes for each surgery type, or numerical effect sizes for each predictor. Because of that, it is hard to know how well these findings apply to every patient or every epilepsy center.

For families and caregivers

For families considering epilepsy surgery for mesial temporal epilepsy with hippocampal sclerosis, this review suggests that surgery is often associated with seizure freedom, but results vary. Better outcomes were most often reported when several presurgery tests agreed about where the seizures were coming from.

This matters because a careful presurgical workup may help doctors estimate the chance of success more clearly. It also suggests that when tests show seizure activity on both sides, the chance of seizure freedom after surgery may be lower. This does not mean surgery will not help, only that the decision may be more complex.

What to watch next

Further studies using consistent outcome measures, clearer reporting of predictor strength, and comparisons across surgery types and longer follow-up would help clarify which preoperative factors are most useful.

Terms in this summary

mesial temporal lobe epilepsy

A type of epilepsy in which seizures start deep in the inner part of the temporal lobe.

hippocampal sclerosis

Scarring and cell loss in the hippocampus, a brain area involved in memory and often linked to temporal lobe epilepsy.

drug-resistant epilepsy

Epilepsy that does not come under good control after trying appropriate seizure medicines.

anterior temporal lobectomy

An operation that removes part of the temporal lobe to treat seizures.

EEG

A test that records the brain's electrical activity and can help show where seizures start.

PET

A brain scan that shows how active different brain areas are by measuring metabolism.

multimodal concordance

When several different tests all point to the same place in the brain as the source of seizures.

systematic review

A study that collects and summarizes results from many previous studies using a planned method.