1. Modeling Volatility Characteristics of Epileptic EEGs using GARCH Models
- Author
-
Jack L. Follis and Dejian Lai
- Subjects
time series characterization ,0301 basic medicine ,Heteroscedasticity ,medicine.diagnostic_test ,business.industry ,Autoregressive conditional heteroskedasticity ,GARCH models ,Pattern recognition ,Electroencephalography ,medicine.disease ,Confidence interval ,Temporal lobe ,03 medical and health sciences ,Epilepsy ,030104 developmental biology ,0302 clinical medicine ,Autoregressive model ,medicine ,epilepsy ,EEG ,Artificial intelligence ,Volatility (finance) ,business ,030217 neurology & neurosurgery ,Mathematics - Abstract
Objective: To determine if there was a difference in the volatility characteristics of seizure and non-seizure onset channels in the intracranial electroencephalogram (EEG) in a patient with temporal lobe epilepsy. Methods: The half-life of volatility for the different EEG channels was determined using Autoregressive Moving Average&ndash, Generalized Autoregressive Conditional Heteroscedasticity (ARMA&ndash, GARCH) models, confidence intervals were constructed using the delta method and an asymptotic method for comparing the half-lives. Results: Clinically determined seizure onsets occurred over strip electrodes named RAST (Right Anterior Subtemporal) and RMST (Right Mid Subtemporal), at locations 2, 3 and 4, on the strip electrodes. The half-lives of volatility for two of the three seizure channels, RAST3 and RAST4, were found to be significantly lower the rest of the channels for six one-minute EEG segments prior to seizure onset and nine one-minute EEG segments of an awake state. The half-lives of volatility for RAST3 and RAST4 were not significantly different to the non-seizure channels for ten one-minute segments of sleep and ten one-minute segments of sleep-to-awake states. The estimates for the half-lives were consistent for randomly selected one-minute EEG segments. Conclusions: The use of GARCH models may be a useful tool in determining hidden properties in epileptiform EEGs that may lead to better understanding of the seizure generating process.
- Published
- 2020