Mapping Brain Function Prior to Surgery

After determining the part of the brain responsible for the seizures (see Diagnosing and Treating Epilepsy in Children), the epilepsy surgical team can map the brain via invasive and non-invasive methods to predict any major problems that could arise when removing the involved area. The neurosurgical approach is tailored to obtain maximal seizure control and minimize any dysfunction afterward. The objective is always to improve quality of life. The removal of a seizure focus may control seizures without causing any change in a patient’s function. In other cases, however, the area of the brain that gives rise to seizures can be located near important areas that control speaking, understanding, moving, remembering, or other critical abilities. Careful testing during the surgical workup and brain mapping process helps protect these functional areas while still achieving successful seizure control.

Non-invasive workup can include different types of scans that identify functional areas as well as differences in brain metabolism that indicate seizure foci. During invasive brain mapping, the brain is stimulated to create a functional map of the area of interest to determine the exact function of the areas being considered for surgical removal as well as the immediately surrounding brain. In some cases, the surgeon will briefly interrupt the function of that part of the brain and check to see whether the patient can still speak, understand, or move. If no function is lost when interrupting the function of that part of the brain, the surgeon can safely remove that portion and stop the seizures.

In some cases, the surgeon may identify some minor loss of function that will occur if the focus of the seizure were to be removed.  It is critical to ensure that the proposed surgery to control seizures will improve quality of life and not create significant long-term deficits for the patient. The information gathered from functional mapping of the brain is shared with the patient and his or her family to help them make an informed decision regarding treatment.