Changes in Interictal Pretreatment and Posttreatment EEG in Childhood Absence Epilepsy

Abstract

Spike and wave discharges (SWDs) are a characteristic manifestation of childhood absence epilepsy (CAE). It has long been believed that they unpredictably emerge from otherwise almost normal interictal EEG. Herein, we demonstrate that pretreatment closed-eyes theta and beta EEG wavelet powers of CAE patients (20 girls and 10 boys, mean age 7.4 ± 1.9 years) are much higher than those of age-matched healthy controls at multiple sites of the 10-20 system. For example, at the C4 site, we observed a 100 and 63% increase in power of theta and beta rhythms, respectively. We were able to compare the baseline and posttreatment wavelet power in 16 patients. Pharmacotherapy brought about a statistically significant decrease in delta and theta wavelet power in all the channels, e.g., for C4 the reduction was equal to 45% (delta) and 63% (theta). The less pronounced attenuation of posttreatment beta waves was observed in 13 channels (36% at C4 site). The beta and theta wavelet power were positively correlated with the percentage of time in seizure (defined as the ratio of the duration of all absences which patients experienced to the duration of recording) for majority of channels. We hypothesize that the increased theta and beta powers result from cortical hyperexcitability and propensity for epileptic spike generation, respectively. We argue that the distinct features of CAE wavelet power spectrum may be used to define an EEG biomarker which could be used for diagnosis and monitoring of patients.

Absence Seizure Detection Algorithm for Portable EEG Devices

“…There is a growing interest in the development of biomarkers of treatment response and side effects ( 35 ). These problems are the subject of our research ( 36 ).…”

Heterogeneity of resting-state EEG features in juvenile myoclonic epilepsy and controls

“…9 The alpha rhythm is of particular interest in IGE due to evidence of its basis in cortico-thalamic interactions, 10 which are central to the generation of generalised seizures/spike-wave discharges 11,12 and functionally and structurally altered in JME. 13,14 Aside from the alpha rhythm, there is evidence of abnormalities in other EEG frequency bands in IGE, such as increased theta 15,16 and beta power. 16 Further, functional networks derived from EEG or MEG activity have altered topology in IGE, as quantified using graph theory, [17][18][19][20][21] with evidence for the most extensive changes in functional connectivity existing in JME compared to other IGE syndromes.…”

“…13,14 Aside from the alpha rhythm, there is evidence of abnormalities in other EEG frequency bands in IGE, such as increased theta 15,16 and beta power. 16 Further, functional networks derived from EEG or MEG activity have altered topology in IGE, as quantified using graph theory, [17][18][19][20][21] with evidence for the most extensive changes in functional connectivity existing in JME compared to other IGE syndromes. 22 Whilst the reported differences in network topology are variable, increased clustering coefficient (indicating increased regularity of networks) is a somewhat consistent finding across studies.…”

Heterogeneity of resting-state EEG features in juvenile myoclonic epilepsy and controls

“… 13 , 14 There is also evidence of abnormalities in other EEG frequency bands in IGE, such as increased theta 15 , 16 and beta power. 16 …”

“… 9 The alpha rhythm is of particular interest in IGE due to evidence of its basis in cortico-thalamic interactions, 10 which are central to the generation of generalized seizures/spike-wave discharges 11 , 12 and functionally and structurally altered in JME. 13 , 14 There is also evidence of abnormalities in other EEG frequency bands in IGE, such as increased theta 15 , 16 and beta power. 16 …”