Neurocritical Care

, Volume 20, Issue 1, pp 32–39 | Cite as

Sensitivity of Compressed Spectral Arrays for Detecting Seizures in Acutely Ill Adults

  • Craig A. Williamson
  • Sarah Wahlster
  • Mouhsin M. ShafiEmail author
  • M. Brandon Westover
Original Article



Continuous EEG recordings (cEEGs) are increasingly used in evaluation of acutely ill adults. Pre-screening using compressed data formats, such as compressed spectral array (CSA), may accelerate EEG review. We tested whether screening with CSA can enable detection of seizures and other relevant patterns.


Two individuals reviewed the CSA displays of 113 cEEGs. While blinded to the raw EEG data, they marked each visually homogeneous CSA segment. An independent experienced electroencephalographer reviewed the raw EEG within 60 s on either side of each mark and recorded any seizures (and isolated epileptiform discharges, periodic epileptiform discharges (PEDs), rhythmic delta activity (RDA), and focal or generalized slowing). Seizures were considered to have been detected if the CSA mark was within 60 s of the seizure. The electroencephalographer then determined the total number of seizures (and other critical findings) for each record by exhaustive, page-by-page review of the entire raw EEG.


Within each of the 39 cEEG recordings containing seizures, one CSA reviewer identified at least one seizure, while the second CSA reviewer identified 38/39 patients with seizures. The overall detection rate was 89.0 % of 1,190 total seizures. When present, an average of 87.9 % of seizures were detected per individual patient. Detection rates for other critical findings were as follows: epileptiform discharges, 94.0 %; PEDs, 100 %; RDA, 97.9 %; focal slowing, 100 %; and generalized slowing, 100 %.


CSA-guided review can support sensitive screening of critical pathological information in cEEG recordings. However, some patients with seizures may not be identified.


Continuous EEG monitoring Quantitative EEG Compressed spectral array Seizures 



This study was supported in part by the following grants: American Brain Foundation (MBW), NIH/NINDS NS062092 (MBW); NIH/NCATS 8KL2TR000168-05 (MS).

Conflict of interest

Drs. Williamson, Wahlster, Shafi, and Westover declare that they have no conflicts of interest.


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Copyright information

© Springer Science+Business Media New York 2013

Authors and Affiliations

  • Craig A. Williamson
    • 1
  • Sarah Wahlster
    • 2
  • Mouhsin M. Shafi
    • 2
    • 3
    Email author
  • M. Brandon Westover
    • 2
  1. 1.Department of NeurosurgeryUniversity of Michigan HospitalAnn ArborUSA
  2. 2.Department of NeurologyMassachusetts General HospitalBostonUSA
  3. 3.Department of NeurologyBeth Israel Deaconess Medical CenterBostonUSA

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