Why is testing needed before epilepsy surgery?

Success rates for epilepsy surgery are constantly improving, and advances in preoperative testing are largely responsible. Proper patient selection and a thorough presurgical workup is critical. 

If a review of the person's experiences with seizure medicines shows that adequate tests of at least a few different medications have not controlled seizures, a person may be referred to a specialized epilepsy center where presurgical testing can be done. 

The preoperative assessment has two general objectives:

  • To maximize seizure control after surgery
  • To minimize disruption of normal brain functioning. 

What is done during a presurgical evaluation?

The number and type of tests that make up the preoperative assessment will depend on the type of surgery being considered. General objectives of the tests include:

  • Assessing the person's current status:
    • These may include evaluations with epilepsy doctors, nurses, psychiatrists, social workers and neuropsychology testing. 
  • Determining the exact location of seizure activity:
    • Tests usually include Video EEG monitoring, MRI scans, and neuropsychology testing. Other tests may include PET, SPECT or MEG studies. 
  • Evaluating the surrounding areas of the brain to determine what kinds of problems the patient might experience after surgery:
    • Wada tests and/or functional MRI scans can help determine the location of language, memory and other important brain functions.
    • Brain mapping at the time of surgery evaluates areas of the brain around the seizure focus.
Authored by: Howard L. Weiner, MD | Joseph I. Sirven, MD
Reviewed by: Joseph I. Sirven, MD | Patricia O. Shafer, RN, MN on 8/2013