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Source localization of rhythmic ictal EEG activity: A study of diagnostic accuracy following STARD criteria

Beniczky, Sandor; Lantz, Goran; Rosenzweig, Ivana; Åkeson, Per LU ; Pedersen, Birthe; Pinborg, Lars H.; Ziebell, Morten; Jespersen, Bo and Fuglsang-Frederiksen, Anders (2013) In Epilepsia 54(10). p.1743-1752
Abstract
PurposeAlthough precise identification of the seizure-onset zone is an essential element of presurgical evaluation, source localization of ictal electroencephalography (EEG) signals has received little attention. The aim of our study was to estimate the accuracy of source localization of rhythmic ictal EEG activity using a distributed source model. MethodsSource localization of rhythmic ictal scalp EEG activity was performed in 42 consecutive cases fulfilling inclusion criteria. The study was designed according to recommendations for studies on diagnostic accuracy (STARD). The initial ictal EEG signals were selected using a standardized method, based on frequency analysis and voltage distribution of the ictal activity. A distributed source... (More)
PurposeAlthough precise identification of the seizure-onset zone is an essential element of presurgical evaluation, source localization of ictal electroencephalography (EEG) signals has received little attention. The aim of our study was to estimate the accuracy of source localization of rhythmic ictal EEG activity using a distributed source model. MethodsSource localization of rhythmic ictal scalp EEG activity was performed in 42 consecutive cases fulfilling inclusion criteria. The study was designed according to recommendations for studies on diagnostic accuracy (STARD). The initial ictal EEG signals were selected using a standardized method, based on frequency analysis and voltage distribution of the ictal activity. A distributed source modellocal autoregressive average (LAURA)was used for the source localization. Sensitivity, specificity, and measurement of agreement (kappa) were determined based on the reference standardthe consensus conclusion of the multidisciplinary epilepsy surgery team. Predictive values were calculated from the surgical outcome of the operated patients. To estimate the clinical value of the ictal source analysis, we compared the likelihood ratios of concordant and discordant results. Source localization was performed blinded to the clinical data, and before the surgical decision. Key FindingsReference standard was available for 33 patients. The ictal source localization had a sensitivity of 70% and a specificity of 76%. The mean measurement of agreement (kappa) was 0.61, corresponding to substantial agreement (95% confidence interval (CI) 0.38-0.84). Twenty patients underwent resective surgery. The positive predictive value (PPV) for seizure freedom was 92% and the negative predictive value (NPV) was 43%. The likelihood ratio was nine times higher for the concordant results, as compared with the discordant ones. SignificanceSource localization of rhythmic ictal activity using a distributed source model (LAURA) for the ictal EEG signals selected with a standardized method is feasible in clinical practice and has a good diagnostic accuracy. Our findings encourage clinical neurophysiologists assessing ictal EEGs to include this method in their armamentarium. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
EEG, Epilepsy, Seizure, Sensitivity, Specificity, Predictive value
in
Epilepsia
volume
54
issue
10
pages
1743 - 1752
publisher
Wiley-Blackwell
external identifiers
  • wos:000325141500007
  • scopus:84885378050
ISSN
0013-9580
DOI
10.1111/epi.12339
language
English
LU publication?
yes
id
d5e0e0a1-10e5-4c57-86ec-89a3338020cc (old id 4171995)
date added to LUP
2013-12-06 12:30:44
date last changed
2019-06-04 01:27:10
@article{d5e0e0a1-10e5-4c57-86ec-89a3338020cc,
  abstract     = {PurposeAlthough precise identification of the seizure-onset zone is an essential element of presurgical evaluation, source localization of ictal electroencephalography (EEG) signals has received little attention. The aim of our study was to estimate the accuracy of source localization of rhythmic ictal EEG activity using a distributed source model. MethodsSource localization of rhythmic ictal scalp EEG activity was performed in 42 consecutive cases fulfilling inclusion criteria. The study was designed according to recommendations for studies on diagnostic accuracy (STARD). The initial ictal EEG signals were selected using a standardized method, based on frequency analysis and voltage distribution of the ictal activity. A distributed source modellocal autoregressive average (LAURA)was used for the source localization. Sensitivity, specificity, and measurement of agreement (kappa) were determined based on the reference standardthe consensus conclusion of the multidisciplinary epilepsy surgery team. Predictive values were calculated from the surgical outcome of the operated patients. To estimate the clinical value of the ictal source analysis, we compared the likelihood ratios of concordant and discordant results. Source localization was performed blinded to the clinical data, and before the surgical decision. Key FindingsReference standard was available for 33 patients. The ictal source localization had a sensitivity of 70% and a specificity of 76%. The mean measurement of agreement (kappa) was 0.61, corresponding to substantial agreement (95% confidence interval (CI) 0.38-0.84). Twenty patients underwent resective surgery. The positive predictive value (PPV) for seizure freedom was 92% and the negative predictive value (NPV) was 43%. The likelihood ratio was nine times higher for the concordant results, as compared with the discordant ones. SignificanceSource localization of rhythmic ictal activity using a distributed source model (LAURA) for the ictal EEG signals selected with a standardized method is feasible in clinical practice and has a good diagnostic accuracy. Our findings encourage clinical neurophysiologists assessing ictal EEGs to include this method in their armamentarium.},
  author       = {Beniczky, Sandor and Lantz, Goran and Rosenzweig, Ivana and Åkeson, Per and Pedersen, Birthe and Pinborg, Lars H. and Ziebell, Morten and Jespersen, Bo and Fuglsang-Frederiksen, Anders},
  issn         = {0013-9580},
  keyword      = {EEG,Epilepsy,Seizure,Sensitivity,Specificity,Predictive value},
  language     = {eng},
  number       = {10},
  pages        = {1743--1752},
  publisher    = {Wiley-Blackwell},
  series       = {Epilepsia},
  title        = {Source localization of rhythmic ictal EEG activity: A study of diagnostic accuracy following STARD criteria},
  url          = {http://dx.doi.org/10.1111/epi.12339},
  volume       = {54},
  year         = {2013},
}