DocumentCode
3213409
Title
The role of delta-modulated high frequency oscillations in seizure state classification
Author
Guirgis, Mirna ; Chinvarun, Yotin ; Carlen, Peter L. ; Bardakjian, Berj L.
Author_Institution
Inst. of Biomater. & Biomed. Eng. (IBBME), Univ. of Toronto, Toronto, ON, Canada
fYear
2013
fDate
3-7 July 2013
Firstpage
6595
Lastpage
6598
Abstract
High frequency oscillations (HFOs), which collectively refer to ripples (80-200 Hz) and fast ripples (>200 Hz), have been implicated as key players in epileptogenesis. However, their presence alone is not in and of itself indicative of a pathological brain state. Rather, spatial origins as well as coexistence with other neural rhythms are essential components in defining pathological HFOs. This study investigates how the phase of the delta rhythm (0.5-4 Hz) modulates the amplitude of HFOs during a seizure episode. Seven seizures recorded from three patients presenting with intractable temporal lobe epilepsy were obtained via intracranial electroencephalography (iEEG) from a 64-electrode grid. Delta modulation of the HFO rhythms was found to emerge at seizure onset and termination regardless of the dynamics present within the seizure episode itself. Moreover, the differences between delta modulating the ripple or fast ripple may be due to the sleep stage of the patient when the seizures were being recorded. Further studies exploring how this modulation changes in space across the grid may also highlight additional properties of this phenomenon. Its temporal pattern suggests that it is a potential iEEG-based biomarker for seizure state classification.
Keywords
biomedical electrodes; delta modulation; diseases; electroencephalography; medical signal processing; neurophysiology; signal classification; sleep; spatiotemporal phenomena; HFO amplitude modulation; HFO rhythm; collective HFO; delta rhythm phase; delta-modulated high frequency oscillation; electrode grid; epileptogenesis; fast ripple delta modulation; frequency 0.5 Hz to 4 Hz; frequency 80 Hz to 200 Hz; iEEG-based biomarker; intracranial electroencephalography; intractable temporal lobe epilepsy; modulation spatial change; neural rhythm coexistence; pathological HFO; pathological brain state; patient sleep stage; ripple spatial origin; seizure episode; seizure onset; seizure patient; seizure state classification; seizure termination; temporal pattern; Couplings; Epilepsy; Frequency modulation; Hafnium compounds; Oscillators; Pathology;
fLanguage
English
Publisher
ieee
Conference_Titel
Engineering in Medicine and Biology Society (EMBC), 2013 35th Annual International Conference of the IEEE
Conference_Location
Osaka
ISSN
1557-170X
Type
conf
DOI
10.1109/EMBC.2013.6611067
Filename
6611067
Link To Document