Article

Detection of temporal lobe spikes: comparing nasopharyngeal, cheek and anterior temporal electrodes to simultaneous subdural recordings.

Department of Clinical Neurophysiology, F02.201, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands.
Clinical Neurophysiology (impact factor: 3.41). 09/2008; 119(8):1771-7. DOI:10.1016/j.clinph.2008.04.011 pp.1771-7
Source: PubMed

ABSTRACT To compare nasopharyngeal (NP), cheek and anterior temporal (AT) electrodes for the detection yield and localization of interictal spikes in temporal lobe epilepsy.
In patients evaluated for epilepsy surgery with subdural electrocorticography electrodes, we simultaneously recorded NP, cheek and AT electrodes. Two observers identified spikes in EEG traces and marked in which channels they occurred. Interobserver agreement was calculated using Cohen's kappa. For localization, data-sets with high interobserver agreement (kappa-value 0.4) were evaluated. The subdural distribution of NP and AT spikes was mapped.
Seven patients were included, six were analyzed for localization. Only 1.5% of spikes recorded by cheek electrodes were not seen on temporal leads, while 25% of NP spikes were not seen on either. Spikes only recorded by NP electrodes had mesiobasal, while AT spikes had lateral temporal distribution.
NP electrodes can increase EEG spike detection rate in temporal lobe epilepsy and are more useful than cheek electrodes. Spikes that are seen only on NP electrodes tend to be mesiobasal temporal lobe spikes.
Adding NP electrodes to scalp EEG can aid interictal spike detection and source localization, especially in short recordings like MEG-EEG.

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Keywords

anterior temporal
 
Cohen's kappa
 
detection yield
 
EEG traces
 
interictal spikes
 
interobserver agreement
 
kappa-value 0.4
 
MEG-EEG
 
mesiobasal temporal lobe spikes
 
nasopharyngeal
 
NP
 
NP electrodes
 
NP spikes
 
patients
 
scalp EEG
 
source localization
 
Spikes
 
subdural distribution
 
subdural electrocorticography electrodes
 
temporal lobe epilepsy