WAVELET ANALYSIS CAN PREDICT WHETHER NEONATES WITH ELECTROGRAPHICAL SEIZURES WILL DEVELOP POST-NEONATAL SEIZURES
Abstract number :
D.08
Submission category :
Year :
2002
Submission ID :
3497
Source :
www.aesnet.org
Presentation date :
12/7/2002 12:00:00 AM
Published date :
Dec 1, 2002, 06:00 AM
Authors :
Shahid Parvez, Masaomi Kitayama, Ryouhei Ishii, Yuko Mizuno-Matsumoto, Reza A. Zoroofy, Abhay Lodha, Ethel Ying, Boriana Parvez, O. Carter Snead III, Hiroshi Otsubo. Neurology, The Hospital for Sick Children, Toronto, ON, Canada; Neonatology, The Hospital
RATIONALE: The clinical outcome of neonatal seizures has been studied with some success. Combination of EEG, clinical findings and neuroimaging studies are useful predictor of developmental outcome, but do not correlate well with post-neonatal seizures (PNS). Wavelet transform is an analysis of non-stationary EEG signals. Using Wavelet, we analyzed the time course of the frequency components in neonatal EEG seizures to investigate whether we could predict PNS.
METHODS: We reviewed the medical records of all neonates admitted to the Hospital for Sick Children (HSC) from 1996 to1997, who had documented electrographical seizures and had at least 18 months of clinical follow up at HSC. Digital EEG system was used to record 16 channels of bipolar neonatal EEG and extracerebral monitoring channels, including eye movements, electrocardiogram, EMG and thoracic (respiratory) movements. Minimum of 30 minutes recording was done at sampling rate of 200 Hz. We reviewed the EEG seizures and selected a pair of electrodes with 20 seconds epoch of preictal and ictal EEG. Gausian Wavelet analysis was applied. We analyzed the following frequency bands: 1-10 Hz, 5-15 Hz, 10-25 Hz and 20-40 Hz.
RESULTS: There were 70 neonates with documented electrographic seizures. 18 of them had clinical follow up for at least 18 months at HSC. Fourteen of the 18 neonates had continuous high intensity tracing at lower frequency: 13 in delta range and 1 in theta range. Thirteen of these 14 patients have PNS (p [lt] 0.01) and are on anti-seizure medications (AED); one is seizure free and is not on AED. The remaining four patients, who did not have continuous high intensity tracing in their Wavelet analysis of EEG seizure, remain seizure free and do not require AED.
CONCLUSIONS: Our study shows that when Wavelet analysis reveals continuous high intensity low frequency tracing in the neonatal EEG seizures, the neonates are highly prone to developing PNS. In addition, absence of continuous high intensity tracing in the Wavelet analysis predicts seizure free outcome. Wavelet analysis can be recommended for the neonates with seizures to predict the development of epilepsy.