This classification is based on two principles, distinguishing first between localized (focal) and generalized epilepsies and second between idiopathic and symptomatic etiologies. The International Classification of Epilepsies and Epileptic Syndromes were proposed by the Committee on Classification and Terminology of the International League Against Epilepsy (9). Overall, repeating the EEG once increases the yield an additional 20% to 30% (7,8).Ĭertain forms of epileptic seizure disorders have special clinical and EEG characteristics irrespective of their etiologies. In children less than 10 years old, the incidence is about 80%. Overall, the incidence of detecting IEDs during the first EEG in adult epilepsy patients is about 30% to 50% (7,8). Multifocal IEDs and focal IEDs, especially at the midline, frontal, and anterior temporal regions are highly (75%–95%) correlated with clinical seizures (5,6). Also IEDs elicited by photic stimulation and generalized spike-wave discharges are less correlated with seizure history compared to focal spikes.
Specificity also varies depending on the type of IEDs: Only about 40% of the patients with benign rolandic spikes of childhood or benign epilepsy of childhood with centrotemporal spikes ( BECTS) and 50% of patients with childhood epilepsy with occipital paroxysms ( benign occipital spikes of childhood) have a history of seizures (5). IEDs are found in 1.9% to 3.5% of healthy children (2,3) and 0.5% of healthy adults (4). The specificity of IEDs is determined by the incidence of IEDs in the normal population (false-positive), compared with that in patients with epilepsy. Also, epileptiform activity arising from deep brain structures such as the medial temporal lobe, subfrontal lobe, or interhemispheric medial cortex may not be readily recorded by scalp electrodes. Detection of IEDs differs, depending on the origin of the epileptiform activity: If a relatively small area of cortex is involved as the epileptogenic zone, IEDs may not be detected by scalp electrodes. IEDs are also recorded more often in children than in adults. Generally, greater seizure frequency is associated with higher yield of IEDs (1). An EEG that includes sleep or is recorded after sleep deprivation increases the yield of IEDs. The likelihood of detecting IEDs varies, depending on seizure type, age, and seizure frequency. Thus, we often rely primarily on IEDs for the diagnosis of epilepsy. In a routine EEG (a recording of approximately 30 min) the chance of recording a clinical seizure (ictal) event is rather rare, unless the patient is having frequent seizures or is in status epilepticus. IEDs, represented by spike or spike-wave discharges, are the most sensitive and specific markers for the diagnosis of seizures. In evaluating the EEG of a patient with possible seizures, we may see interictal epileptiform discharges (IEDs) and/or nonspecific paroxysmal discharges, with or without focal or diffuse slowing. PAROXYSMAL DISCHARGES AND SEIZURE DIAGNOSIS The epilepsies of premature babies or neonates are beyond the scope of this chapter. Maybe tommorrow.In this chapter we address the electroencephalography (EEG) of pediatric epilepsies.
I'll post a picture of the screen when she goes to bed so you guys can see what Im talking about.Īnyway, I was hoping the Neuro would stop by and give us some insight but no dice.
I know it may be totally normal for her but everyone is acting like it looks strange. The nurse asked me what she's doing in her sleep when it happens and she is literally not moving one s really strange. Literally the second she wakes up, the events and spikes stop. However, she's had over 800 spikes and 37 events while sleeping today. Otherwise its completely normal while she's awake. When shes awake, there have been only 2 spikes, both really big and they were immediately after waking. Now that its been hooked up longer, I can see the dramatic changes between sleep and wakeful times. I wanted to ask but didnt because I dont want some ignorant nurse scaring me because she's not a neurologist. Can you have a seizure without any outward movement while sleeping? No one has said a single word about her EEG, but have been in our room many times eyeing the screen suspiciously.