Utility of scalp‐recorded ictal electroencephalograms in childhood epilepsy with complex partial seizures

Abstract

The findings of the present study indicate that ictal EEG recordings are useful for determining the epileptogenic area in epilepsy with complex partial seizures, provided that more than 75% of the ictal recordings show the same ictal onset area.

Ictal fear depends on the cerebral laterality of the epileptic activity

“…In addition, we could have made erroneous inferences of neural activation of the focus during the fear symptom in some cases. That determination of side of focus is an imperfect art is attested to by: 1) inconsistency of focus determination in repeated scalp recordings (Yoshinaga et al 2004); 2) incongruence of metabolic imaging, functional imaging, surface and depth EEG (Stefan et al 1987); 3) persistence of seizures in lobectomized patients, at least 16%, in outcome studies (see McIntosh et al 2001 for a meta‐analysis of the outcome studies) and 11% in the present data set. That assignation of fear symptoms can be incorrectly assigned to the epileptic aura or ictus is suggested by the facts that; 1) there are cases in the literature (excluded from the present review) in whom fear symptoms were initially thought to be ictal (including those based on EEG), and in whom, after in depth investigation, those symptoms were no longer thought to be related to the actual ictus (Alsaadi and Vinter Marquez 2005); 2) persistence of seizures in patients treated with anticonvulsants (McCorrya and Chadwicka 2004) (48% in the present set of cases).…”

“…That assignation of fear symptoms can be incorrectly assigned to the epileptic aura or ictus is suggested by the facts that; 1) there are cases in the literature (excluded from the present review) in whom fear symptoms were initially thought to be ictal (including those based on EEG), and in whom, after in depth investigation, those symptoms were no longer thought to be related to the actual ictus (Alsaadi and Vinter Marquez 2005); 2) persistence of seizures in patients treated with anticonvulsants (McCorrya and Chadwicka 2004) (48% in the present set of cases). Finally, although ictal spiking is correlated with increased perfusion as measured by SPECT and fMRI, the correlation is not perfect (Kuhl et al 2004, Rougier et al 1999, Yoshinaga et al 2004). In short, in our judgment, considering the numerous technical and methodological sources of error in estimating hemispheric specialization using ictal phenomena, the right focus prevalence observed here is remarkably high.…”

“…It has consistently been found that the focal area determined by scalp EEG, might be, and often is, hypoperfused interictally and even ictally. However, spiking observed ictally on the scalp EEG has consistently been found to correspond to increased perfusion in the brain area under which the spiking is observed (Kuhl et al 2004, Rougier et al 1999. Yoshinaga et al 2004).…”

“…However, spiking observed ictally on the scalp EEG has consistently been found to correspond to increased perfusion in the brain area under which the spiking is observed (Kuhl et al 2004, Rougier et al 1999. Yoshinaga et al 2004). Furthermore, the focus area of interictal spiking is highly predictive (> 90%) of the focus area of subsequent ictal spiking (Blume et al 1991, Stefan et al 1987).…”

Advanced Treatments for Childhood Epilepsy

“…In a study of 486 seizures among 72 children and adults in whom the epileptogenic zone location was verified by postoperative seizure freedom, ictal scalp EEG localized correctly in 72% of cases, more often in temporal than extratemporal epilepsy. 34 Emerging evidence, however, demonstrates that in the setting of a clear structural lesion, nonlocalizing and even nonlateralizing interictal or ictal EEG features do not preclude successful resective epilepsy surgery, which can treat children with severe epileptic encephalopathies. 35 Neuroimaging.…”