One of the most important considerations when performing epilepsy surgery is to remove the seizure focus (the area of the brain where seizures begin) and avoid the healthy brain cells nearby. In doing so, patients who have surgery are less likely to experience side effects or functional deficits after surgery. When removing a seizure focus in the left hemisphere, it is important to avoid the language centres that control speech and understanding.

Traditionally, it has been assumed that if you avoid the two main areas in the brain associated with speech – Broca’s and Wernicke’s areas – there would be minimal post-surgery impairments in language. However, through more dynamic studies of the brain, we now know that speech production and understanding language may involve other networks outside of Broca’s and Wernicke’s areas, and may also vary from patient to patient.

Drs. Erin White and Elizabeth Pang from the Hospital for Sick Children and Dr. Taufik Valiante from Toronto Western Hospital have been conducting a series of studies to improve the mapping of language networks in the brain. Using electroencephalography (EEG) brain wave monitoring and a variety of language stimuli, they are able to identify the language processing areas in the brain. Importantly, this is being done with conventional scalp electrodes before surgery, instead of using the typical electrodes placed on the exposed brain during surgery.

Preliminary results seen in healthy children and adults highlight the effectiveness of using this protocol for identifying language networks within the brain. Drs. White, Pang and Valiante are currently in the process of conducting a study in children with drug-resistant epilepsy to see if pre-surgery monitoring can be just as effective as monitoring during surgery, potentially showing that this less invasive, pre-surgical method can reduce the risk of speech impairments following surgery.

Leave a Reply

Your email address will not be published. Required fields are marked *

Post comment