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.