Distinct electrographic abnormalities to help classification can be identified among different electroclinical syndromes. Reflex seizure-related EEG abnormalities can be elicited by the use of triggers such as cognitive tasks and pattern stimulation during the EEG recording in selected patients. Sleep, sleep deprivation, hyperventilation, intermittent photic stimulation, eye closure, and fixation-off are often used as activation techniques to increase the diagnostic yield of EEG recordings. There are circadian variations of generalized epileptiform discharges. However, admixed with typical changes, atypical epileptiform discharges are also commonly seen in GGE.
Other classic EEG abnormalities are polyspikes, epileptiform K-complexes and sleep spindles, polyspike-wave discharges, occipital intermittent rhythmic delta activity, eye-closure sensitivity, fixation-off sensitivity, and photoparoxysmal response. The main EEG feature of GGE is bilateral, synchronous, symmetric, and generalized spike-wave complex. Genetic generalized epilepsy (GGE) consists of several syndromes diagnosed and classified on the basis of clinical features and electroencephalographic (EEG) abnormalities. 2Department of Neuroscience, Monash Medical Centre, Melbourne, VIC, Australia.Vincent’s Hospital, The University of Melbourne, Melbourne, VIC, Australia
