The most important part of the PHASE I evaluation is continuous computer assisted EEG monitoring with simultaneous video recording. The goal of monitoring is to record a patient's typical events. During the hospital stay, a patient's medications may be lowered in order to provoke seizures. Other procedures such as sleep deprivation, flashing lights, and hyperventilation may be performed for the same reason.
Continuous video and EEG recording is important for several reasons. Monitoring of seizures may help to establish a diagnosis when the cause of the seizures is unclear (differential diagnosis). It is useful in quantification of seizures and classification of seizure type. It is also a critical part of the evaluation of patients for epilepsy surgery, because it helps to identify the abnormal region of brain that is causing the seizures. This abnormal region is called the epileptogenic zone.
Neuropsychological testing may be performed during the PHASE I evaluation. This kind of testing helps to better understand a person's language and memory impairments, thereby identifying regions of the brain that are not working correctly. In addition, a psychiatrist evaluates many patients during PHASE I monitoring in order to understand and treat other problems. In many cases, the problems are directly related to the person's seizures.
Often, structural and functional brain imaging is necessary. For instance, a MRI of the brain looks for structural abnormalities that can cause seizures. A SPECT scan measures blood flow during a seizure in order to determine the part of the brain that is causing the seizure. The WADA test is a specialized way to evaluate language and memory function prior to surgery.
At the end of PHASE I, if the patient was admitted to the CCEC for differential diagnosis, he/she is discharged home on anticonvulsant medication(s), and returns to the Center or the referring physician for a follow-up visit. If the patient was admitted to the CCEC for a surgical evaluation, he/she is disconnected from the monitoring equipment, and medication is resumed. Once the antiepileptic drug levels are acceptable, the patient is discharged home. Within several weeks of discharge, a team conference is held to review all the hospital findings, and results of testing. If the epileptogenic zone could not be identified during Phase I monitoring, recommendations may be made to readmit the patient for a PHASE II evaluation. In cases where the team is able to identify the exact onset of the seizures, a recommendation may be made to proceed directly to PHASE III - epilepsy surgery.