Neuropsychological testing usually consists of a battery of cognitive tests designed to measure specific mental abilities quantitatively, allowing a comparison to expected normal ranges for each task. The performance on individual tasks provides important information about the function of specific brain regions. For example, impaired short-term memory may indicate an abnormality in the function of a part of the brain called the temporal lobe.

Patients with epilepsy occasionally suffer from memory problems or other cognitive difficulties. These problems can result from an underlying brain disease that is causing the seizures. In addition, repeated, uncontrolled seizures can impair learning and other cognitive abilities. Under these circumstances, patients may benefit from a quantitative assessment of their intellectual function in order to gain insight into the severity and the cause of their seizures. In some cases, anti-epileptic medications themselves may also produce mild cognitive difficulties.

In the special circumstance in which a patient is being evaluated for surgical treatment of epilepsy, neuropsychological testing can provide information about the parts of the brain producing the seizures. Since recurrent seizures over long periods of time may interfere with brain function, neuropsychological testing is used to detect which parts of the brain are not functioning normally, to help locate the origin of the patient's seizures within the brain. This information is then used in conjunction with other tests to decide what parts of the brain could be removed to prevent further seizures.