Epileptiform electroencephalographic patterns

Electroencephalography (EEG) is the most useful test for assessment of patients with epilepsy. It can help establish the diagnosis of epilepsy and determine the type of seizure disorder and its site of origin. Epileptiform abnormalities in the EEG tracing may be focal or generalized. The main types of focal epileptiform discharges arise from the temporal, frontal, occipital, centroparietal, centrotemporal, and midline regions of the brain. Generalized epileptiform discharges consist of the 3-Hz spike-and-wave, slow spike-and-wave, atypical spike-and-wave, paroxysmal fast activity, and hypsarrhythmic patterns. Status epilepticus is manifested by continuous epileptiform discharges or recurrent seizure activity without interim recovery, which can occur in a generalized or focal manner. Benign epileptiform variants unassociated with seizures can also be present in the EEG. Included in this category are the "14 & 6" positive bursts, small sharp spikes, wicket waves, 6-Hz spike-and-wave discharges, and rhythmic temporal theta activity. The EEG findings should be interpreted in the context of the overall clinical picture.