Magnetoencephalography (MEG) is a new method for non-invasive imaging of brain activity. It is similar to electroencephalography (EEG), but it tracks brain activity using magnetic field changes rather than electrical field changes. MEG is better than EEG at tracking brain activity that occurs within the brain. MEG can also be combined with magnetic resonance imaging (MRI) – which provides a picture of the brain’s structure – to accurately pinpoint areas within the brain that cause seizures.
Together with colleagues at the Hospital for Sick Children and Toronto Western Hospital, Dr. Douglas Cheyne’s group is developing new ways of combining MEG and MRI to localize areas in the brain that are generating “interictal spikes”. Interictal spikes are brief abnormalities in brain activity that occur between seizures, and can be used to help find the region of the brain where seizures begin. Finding the area where seizures start (known as an ‘epileptic focus’) can then be used to guide surgery, where this part of the brain is removed.
Dr. Cheyne’s approach to using MEG and MRI for brain imaging may eliminate the need to place electrodes (sensors) directly onto the brain to find the epileptic focus. Instead, doctors and researchers may be able to obtain the same information using MEG and MRI but with a less invasive, safer approach.