Nonconvulsive Status Epilepticus: Validating the Salzburg Criteria Against an Expert EEG Examiner

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Abstract

PURPOSE: Rapid and correct diagnosis of nonconvulsive status epilepticus (NCSE) is crucial for optimal treatment. However, electroencephalographic diagnosis can be challenging. Salzburg Consensus Criteria (SCC) have been proposed to facilitate correct diagnosis, but their validity needs to be further established.

METHODS: We retrospectively reanalyzed the first EEG in adult patients (n = 284) referred under the suspicion of NCSE at our institution in 2014. Nonconvulsive status epilepticus or possible NCSE was diagnosed according to the SCC by an examiner specifically trained in SCC and was compared with the original diagnosis made by an expert EEG examiner, which in this context served as the reference standard, to assess the validity of the criteria. Furthermore, the clinical outcome for patients not diagnosed using SCC (false-negatives) was examined.

RESULTS: Nonconvulsive status epilepticus or possible NCSE was diagnosed in 40 patients by the inexperienced reader using the SCC, blinded to other clinical data, and in 47 patients by the experienced reader, not blinded to the clinical data, who did not use SCC. There were eight false-negatives, one false-positive, 39 true-positives, and 236 true-negatives. Concordance between SCC and the reference standard was high (k = 0.88 [95% confidence interval, 0.80 to 0.96]). Four of the eight false-negatives suffered from anoxic encephalopathy. The remainder had a history of epilepsy and returned to preictal functional state.

CONCLUSIONS: The SCC for NCSE implemented by an inexperienced EEG reader, blinded to all other data, yielded results highly concordant with the evaluation of EEG by an experienced reader. False-negative diagnoses were associated with postictal states or anoxic encephalopathy.

Original languageEnglish
JournalJournal of Clinical Neurophysiology
Volume36
Issue number2
Pages (from-to)141-145
ISSN0736-0258
DOIs
Publication statusPublished - 1. Mar 2019

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Electroencephalography
Confidence Intervals

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@article{38f0cdce3b7d48789d4036458d475adf,
title = "Nonconvulsive Status Epilepticus: Validating the Salzburg Criteria Against an Expert EEG Examiner",
abstract = "PURPOSE: Rapid and correct diagnosis of nonconvulsive status epilepticus (NCSE) is crucial for optimal treatment. However, electroencephalographic diagnosis can be challenging. Salzburg Consensus Criteria (SCC) have been proposed to facilitate correct diagnosis, but their validity needs to be further established.METHODS: We retrospectively reanalyzed the first EEG in adult patients (n = 284) referred under the suspicion of NCSE at our institution in 2014. Nonconvulsive status epilepticus or possible NCSE was diagnosed according to the SCC by an examiner specifically trained in SCC and was compared with the original diagnosis made by an expert EEG examiner, which in this context served as the reference standard, to assess the validity of the criteria. Furthermore, the clinical outcome for patients not diagnosed using SCC (false-negatives) was examined.RESULTS: Nonconvulsive status epilepticus or possible NCSE was diagnosed in 40 patients by the inexperienced reader using the SCC, blinded to other clinical data, and in 47 patients by the experienced reader, not blinded to the clinical data, who did not use SCC. There were eight false-negatives, one false-positive, 39 true-positives, and 236 true-negatives. Concordance between SCC and the reference standard was high (k = 0.88 [95{\%} confidence interval, 0.80 to 0.96]). Four of the eight false-negatives suffered from anoxic encephalopathy. The remainder had a history of epilepsy and returned to preictal functional state.CONCLUSIONS: The SCC for NCSE implemented by an inexperienced EEG reader, blinded to all other data, yielded results highly concordant with the evaluation of EEG by an experienced reader. False-negative diagnoses were associated with postictal states or anoxic encephalopathy.",
author = "Krogstad, {Martin H} and Hans H{\o}genhaven and Beier, {Christoph P} and Thomas Kr{\o}ig{\aa}rd",
year = "2019",
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language = "English",
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Nonconvulsive Status Epilepticus : Validating the Salzburg Criteria Against an Expert EEG Examiner. / Krogstad, Martin H; Høgenhaven, Hans; Beier, Christoph P; Krøigård, Thomas.

In: Journal of Clinical Neurophysiology, Vol. 36, No. 2, 01.03.2019, p. 141-145.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Nonconvulsive Status Epilepticus

T2 - Validating the Salzburg Criteria Against an Expert EEG Examiner

AU - Krogstad, Martin H

AU - Høgenhaven, Hans

AU - Beier, Christoph P

AU - Krøigård, Thomas

PY - 2019/3/1

Y1 - 2019/3/1

N2 - PURPOSE: Rapid and correct diagnosis of nonconvulsive status epilepticus (NCSE) is crucial for optimal treatment. However, electroencephalographic diagnosis can be challenging. Salzburg Consensus Criteria (SCC) have been proposed to facilitate correct diagnosis, but their validity needs to be further established.METHODS: We retrospectively reanalyzed the first EEG in adult patients (n = 284) referred under the suspicion of NCSE at our institution in 2014. Nonconvulsive status epilepticus or possible NCSE was diagnosed according to the SCC by an examiner specifically trained in SCC and was compared with the original diagnosis made by an expert EEG examiner, which in this context served as the reference standard, to assess the validity of the criteria. Furthermore, the clinical outcome for patients not diagnosed using SCC (false-negatives) was examined.RESULTS: Nonconvulsive status epilepticus or possible NCSE was diagnosed in 40 patients by the inexperienced reader using the SCC, blinded to other clinical data, and in 47 patients by the experienced reader, not blinded to the clinical data, who did not use SCC. There were eight false-negatives, one false-positive, 39 true-positives, and 236 true-negatives. Concordance between SCC and the reference standard was high (k = 0.88 [95% confidence interval, 0.80 to 0.96]). Four of the eight false-negatives suffered from anoxic encephalopathy. The remainder had a history of epilepsy and returned to preictal functional state.CONCLUSIONS: The SCC for NCSE implemented by an inexperienced EEG reader, blinded to all other data, yielded results highly concordant with the evaluation of EEG by an experienced reader. False-negative diagnoses were associated with postictal states or anoxic encephalopathy.

AB - PURPOSE: Rapid and correct diagnosis of nonconvulsive status epilepticus (NCSE) is crucial for optimal treatment. However, electroencephalographic diagnosis can be challenging. Salzburg Consensus Criteria (SCC) have been proposed to facilitate correct diagnosis, but their validity needs to be further established.METHODS: We retrospectively reanalyzed the first EEG in adult patients (n = 284) referred under the suspicion of NCSE at our institution in 2014. Nonconvulsive status epilepticus or possible NCSE was diagnosed according to the SCC by an examiner specifically trained in SCC and was compared with the original diagnosis made by an expert EEG examiner, which in this context served as the reference standard, to assess the validity of the criteria. Furthermore, the clinical outcome for patients not diagnosed using SCC (false-negatives) was examined.RESULTS: Nonconvulsive status epilepticus or possible NCSE was diagnosed in 40 patients by the inexperienced reader using the SCC, blinded to other clinical data, and in 47 patients by the experienced reader, not blinded to the clinical data, who did not use SCC. There were eight false-negatives, one false-positive, 39 true-positives, and 236 true-negatives. Concordance between SCC and the reference standard was high (k = 0.88 [95% confidence interval, 0.80 to 0.96]). Four of the eight false-negatives suffered from anoxic encephalopathy. The remainder had a history of epilepsy and returned to preictal functional state.CONCLUSIONS: The SCC for NCSE implemented by an inexperienced EEG reader, blinded to all other data, yielded results highly concordant with the evaluation of EEG by an experienced reader. False-negative diagnoses were associated with postictal states or anoxic encephalopathy.

U2 - 10.1097/WNP.0000000000000556

DO - 10.1097/WNP.0000000000000556

M3 - Journal article

C2 - 30585889

VL - 36

SP - 141

EP - 145

JO - Journal of Clinical Neurophysiology

JF - Journal of Clinical Neurophysiology

SN - 0736-0258

IS - 2

ER -