Added clinical value of the inferior temporal EEG electrode chain

Justesen, Anders Bach; Johansen, Ann Berit Eskelund; Martinussen, Noomi Ida; Wasserman, Danielle; Terney, Daniella; Meritam, Pirgit; Gardella, Elena; Beniczky, Sándor

doi:10.1016/j.clinph.2017.09.113

Cited by 23 publications

(20 citation statements)

References 28 publications

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“…In the current study an extended 10–20 (31‐electrode scalp montage) was used, which includes an inferior temporal row of scalp electrodes. Although the extended 10–20 montage is superior to the standard 10–20 (19‐electrode scalp montage) for identifying temporal lobe IEDs, 14 our study does suggest the potential value of high spatial resolution scalp EEG for extratemporal lobe epilepsy 51 …”

Section: Discussionmentioning

confidence: 70%

“…EEG studies were performed using an extended International 10-20 system (31 electrodes that include the inferior temporal chain). 13,14 Interictal findings were coded based on laterality as bilateral interictal epileptiform discharges (IEDs), unilateral IEDs (more than 80% of the discharges on one side 15,16 ), or no IEDs. Based on the EEG report description, we collected data on the typology of the IEDs (sharp waves, spikes/polyspikes, both, or no IEDs), on the percent of temporal lobe IEDs, and on the frequency of discharges (rare or frequent).…”

Section: Eegvariablesmentioning

confidence: 99%

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Improving the prediction of epilepsy surgery outcomes using basic scalp EEG findings

et al. 2021

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Objective:This study aims to evaluate the role of scalp electroencephalography (EEG; ictal and interictal patterns) in predicting resective epilepsy surgery outcomes. We use the data to further develop a nomogram to predict seizure freedom.Methods:We retrospectively reviewed the scalp EEG findings and clinical data of patients who underwent surgical resection at three epilepsy centers. Using both EEG and clinical variables categorized into 13 isolated candidate predictors and 6 interaction terms, we built a multivariable Cox proportional hazards model to predict seizure freedom 2 years after surgery. Harrell's step-down procedure was used to sequentially eliminate the least-informative variables from the model until the change in the concordance index (c-index) with variable removal was less than 0.01. We created a separate model using only clinical variables. Discrimination of the two models was compared to evaluate the role of scalp EEG in seizure-freedom prediction.Results:Four hundred seventy patient records were analyzed. Following internal validation, the full Clinical + EEG model achieved an optimism-corrected c-index of 0.65, whereas the c-index of the model without EEG data was 0.59. The presence of focal to bilateral tonic-clonic seizures (FBTCS), high preoperative seizure frequency, absence of hippocampal sclerosis, and presence of nonlocalizable seizures predicted worse outcome. The presence of FBTCS had the largest impact for predicting outcome. The analysis of the models' interactions showed that in patients with unilateral interictal epileptiform discharges (IEDs), temporal lobe surgery cases had a better outcome. In cases with bilateral IEDs, abnormal magnetic resonance imaging (MRI) predicted worse outcomes, and in cases without IEDs, patients with extratemporal epilepsy and abnormal MRI had better outcomes.

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Section: Discussionmentioning

confidence: 70%

Section: Eegvariablesmentioning

confidence: 99%

Improving the prediction of epilepsy surgery outcomes using basic scalp EEG findings

et al. 2021

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“…Adequate coverage of the head, especially inferior temporal regions, is of importance. Although this was not an inclusion criteria, all of our included HR-ESI studies used whole-head electrode coverages, including subtemporal regions therefore improving localization accuracy [75,78,7].…”

Section: Discussionmentioning

confidence: 99%

Diagnostic accuracy of interictal source imaging in presurgical epilepsy evaluation: A systematic review from the E-PILEPSY consortium

Mouthaan

Rados

Boon

et al. 2019

Clinical Neurophysiology

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Interictal high resolution (HR-) electric source imaging (ESI) and magnetic source imaging (MSI) are non-invasive tools to aid epileptogenic zone localization in epilepsy surgery candidates. We carried out a systematic review on the diagnostic accuracy and quality of evidence of these modalities. MethodsEmbase, Pubmed and the Cochrane database were searched on 13 February 2017.Diagnostic accuracy studies taking post-surgical seizure outcome as reference standard were selected. Quality appraisal was based on the QUADAS-2 framework. ResultsEleven studies were included: eight MSI (n=267), three HR-ESI (n=127) studies. None was free of bias. This mostly involved: selection of operated patients only, interference of source imaging with surgical decision, and exclusion of indeterminate results. Summary sensitivity and specificity estimates were 82% (95% CI: 75-88%) and 53% (95% CI: 37-68%) for overall source imaging, with no statistical difference between MSI and HR-ESI. Specificity is higher when partially concordant results were included as non-concordant (p<0.05). Inclusion of indeterminate test results as non-concordant lowered sensitivity (p<0.05). ConclusionsSource imaging has a relatively high sensitivity but low specificity for identification of the epileptogenic zone. SignificanceWe need higher quality studies allowing unbiased test evaluation to determine the added value and diagnostic accuracy of source imaging in the presurgical workup of refractory focal epilepsy. Highlights Interictal source imaging studies are biased and show heterogeneity for population and test method  Source imaging sensitivity and specificity was 82% (95% CI: 75-88%) and 53% (37-68%) respectively  Diagnostic accuracy for (extra)temporal and (non)-lesional patients show no statistical differences

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“…The standard 10–20 system does not include electrodes over the inferior part of the head which disfavors the proper recording of activities in the inferior-basal and anterior part of the temporal lobe where activity originating or propagating from the mesial temporal structures is maximal (61, 62) (Figure 4B). Missing these electrodes can lead to mislocalization of activities originating from the mesial temporal lobe (60, 63). It has therefore been recommended that at least 3 inferior electrodes on each side should be added to the standard 10–20 system in clinical routine (64).…”

Section: Number and Positioning Of The Electrodesmentioning

confidence: 99%

EEG Source Imaging: A Practical Review of the Analysis Steps

2019

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The electroencephalogram (EEG) is one of the oldest technologies to measure neuronal activity of the human brain. It has its undisputed value in clinical diagnosis, particularly (but not exclusively) in the identification of epilepsy and sleep disorders and in the evaluation of dysfunctions in sensory transmission pathways. With the advancement of digital technologies, the analysis of EEG has moved from pure visual inspection of amplitude and frequency modulations over time to a comprehensive exploration of the temporal and spatial characteristics of the recorded signals. Today, EEG is accepted as a powerful tool to capture brain function with the unique advantage of measuring neuronal processes in the time frame in which these processes occur, namely in the sub-second range. However, it is generally stated that EEG suffers from a poor spatial resolution that makes it difficult to infer to the location of the brain areas generating the neuronal activity measured on the scalp. This statement has challenged a whole community of biomedical engineers to offer solutions to localize more precisely and more reliably the generators of the EEG activity. High-density EEG systems combined with precise information of the head anatomy and sophisticated source localization algorithms now exist that convert the EEG to a true neuroimaging modality. With these tools in hand and with the fact that EEG still remains versatile, inexpensive and portable, electrical neuroimaging has become a widely used technology to study the functions of the pathological and healthy human brain. However, several steps are needed to pass from the recording of the EEG to 3-dimensional images of neuronal activity. This review explains these different steps and illustrates them in a comprehensive analysis pipeline integrated in a stand-alone freely available academic software: Cartool. The information about how the different steps are performed in Cartool is only meant as a suggestion. Other EEG source imaging software may apply similar or different approaches to the different steps.

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Added clinical value of the inferior temporal EEG electrode chain

Cited by 23 publications

References 28 publications

Improving the prediction of epilepsy surgery outcomes using basic scalp EEG findings

Improving the prediction of epilepsy surgery outcomes using basic scalp EEG findings

Diagnostic accuracy of interictal source imaging in presurgical epilepsy evaluation: A systematic review from the E-PILEPSY consortium

EEG Source Imaging: A Practical Review of the Analysis Steps

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