Waveform Window #20 Specific Eeg Patterns

Abstract

Specific EEG patterns are EEG patterns that are readily distinguishable from the background. These patterns can be normal or they can be abnormal. Normal specific patterns come in many forms. Some normal variants appear epileptiform but are nonepileptogenic in their significance, meaning that the variants have no established correlation with clinical seizures. Some variants are very rhythmic and must be examined by considering the location of the pattern, the background activity from which the pattern arises, and the state of the patient. Some specific EEG patterns are abnormal such as periodic lateralized epileptiform discharges (PLEDs), hypsarrhythmia, or 3Hz generalized spike and wave. Abnormal specific EEG patterns can sometimes help lead to the patient's diagnosis. These patterns can be challenging and fun to investigate and recognize. During the recording, the neurodiagnostic technologist must do all he/she can to identify the pattern, e.g., by changing the patient's level of consciousness (awake vs sleep, eyes open vs eye closed, responding or not responding to commands), verifying that the pattern is not artifactual, and any other procedures that block or bring out the suspected pattern. Creating a department archive of specific EEG patterns builds a collection of waveforms for students, new technologists, residents, fellows, and anyone studying for board exams.