Epilepsy surgery can be a lifesaving measure for children with intractable epilepsy. But even when the surgery is successful at curing epilepsy, it can introduce language impediments and other cognitive issues. Several tests try to predict how surgery might affect a person’s language ability.
Functional magnetic resonance imaging (fMRI) is the preferred way to determine if a brain area targeted during surgery is the same area that the child relies on for language or speech. During an fMRI scan, the child is asked to complete tasks that activate different parts of the brain, sending oxygen to these areas. The fMRI machine then measures these changes in oxygen and displays them as a map so that the surgeon can see which areas of the brain are active during each task. This helps the surgeon determine where the edges of brain surgery should lie to avoid tampering with healthy brain tissue. Because slight movements can throw off the fMRI scanner and produce blurry images, some tasks may need to be repeated.
An fMRI scan is less expensive and less likely to cause injury than other predictive tests, such as Wada (intracarotid amobarbital test). But fMRI predicts only language skills while other tests can predict both language and memory. With regards to language prediction, fMRI is about as accurate as Wada. fMRI has successfully predicted language function after surgery in people with medial temporal lobe epilepsy, temporal epilepsy in general, and extratemporal epilepsy. However, fMRI is less accurate in people with temporal neocortical epilepsy or temporal tumors.
Presurgical language fMRI: Mapping of six critical regions
Combined electroencephalography-functional magnetic resonance imaging and electrical source imaging improves localization of pediatric focal epilepsy.
Does education play a role in language reorganization after surgery in drug refractory temporal lobe epilepsy: An fMRI based study?
Pediatric epilepsy surgery: Preoperative assessment and surgical treatment
Comparing the Intracarotid Amobarbital Test and Functional MRI for the Presurgical Evaluation of Language in Epilepsy
On the relative merits of invasive and non-invasive pre-surgical brain mapping: New tools in ablative epilepsy surgery
Lateralizing language function with pre-operative functional magnetic resonance imaging in early proficient bilingual patients
Practice guideline summary: Use of fMRI in the presurgical evaluation of patients with epilepsy: Report of the Guideline Development, Dissemination, and Implementation Subcommittee of the American Academy of Neurology
An Overview of fMRI from Psychcentral
Practice guideline summary: Use of fMRI in the presurgical evaluation of patients with epilepsy. Report of the Guideline Development, Dissemination, and Implementation Subcommittee of the American Academy of Neurology