The Spike-Wave Index of the First 100 Seconds of Sleep Can Be a Reliable Scoring Method for Electrographic Status
Neil Kulkarni1, Dara V F Albert1, Brett Klamer1
1Nationwide Children's Hospital, Neurology, Columbus, Ohio, U.S.A.; and.
Introduction:
Electrical status epilepticus in sleep (ESES) is an electrographic pattern in which interictal epileptiform activity is augmented by the transition to sleep, with non-rapid eye movement sleep state characterized by near-continuous lateralized or bilateral epileptiform discharges. The aim of this study was to measure the reliability of the spike-wave index (SWI) of the first 100 seconds of sleep as a tool for the diagnosis of ESES.
Methods:
One hundred forty studies from 60 unique patients met the inclusion. Two neurophysiologists calculated the SWI of the first 100 seconds of spontaneous stage II non-rapid eye movement sleep. This was compared with the SWI of the first 5 minutes of non-rapid eye movement sleep and the cumulative SWI of three 5-minute bins of sleep. Agreement between the three SWI methods were analyzed using several statistical tools and methods.
Results:
Using an SWI of 50% as a diagnostic cutoff, 57% of records had a diagnosis of ESES based on the first 100 seconds of sleep. Fifty-four percent of records had a diagnosis of ESES based on the method of using the SWI of three bins. This resulted in a diagnostic accuracy of 92%, sensitivity of 96%, and specificity of 88%. Positive predictive values of children diagnosed with ESES using the first 100 seconds of sleep, compared with 3 combined bins, was determined to be 90% and a negative predictive value was determined to be 95%.
Conclusions:
This analysis confirmed the diagnostic accuracy of using the SWI of the first 100 seconds of sleep and the cumulative total of three 5-minute bins.
