MRI brain scans are an essential part of the clinical tests done before seizure surgery. MRIs can help surgeons see where the part of the brain is that causes seizures, which they can then remove during surgery. But structural MRIs – those that only show the shape of the brain – cannot tell a surgeon how specific brain areas are working, which is key to knowing what areas to avoid and how likely the surgery is to be successful. To get this crucial information on brain function, a different form of brain imaging is needed.
Dr. Mary Pat McAndrews and her team at Toronto Western Hospital are conducting a research study using functional MRI (fMRI; a type of MRI brain scan that shows how brain areas and networks are involved in language and memory), in addition to EEG brain wave recordings and past medical records. Both fMRI and EEG are done while patients are ‘at rest’ and while doing specific language and memory tasks, providing key insights into how important brain networks are organized.
To date, Dr. McAndrews and her team have looked at the ‘at rest’ fMRI brain scans to examine the networks and connections within the part of the brain known as the hippocampus (affected in temporal lobe epilepsy). They found that the connections within the hippocampus ‘at rest’ were linked to how individuals performed on memory tests and can predict the degree of memory loss after surgical removal of the hippocampus.
Ongoing work in this study will also be able to tell whether EEG, which provides complementary information about the timing of different brain processes, can help predict surgical outcomes. Dr. McAndrews’ team is also looking at new ways to measure connections and networks within the brain, as well as testing different fMRI and EEG settings that will reduce seizures and preserve intelligence.
The hope is that these advanced brain imaging techniques and medical information will help improve predictions of surgery outcomes and allow the patient to make an informed decision when weighing the costs and benefits of seizure surgery.