Spatial relationship between fast and slow components of ictal activities and interictal epileptiform discharges in epileptic spasms

Tomoyuki Akiyama; Mari Akiyama; Katsuhiro Kobayashi; Tohru Okanishi; Cyrus G Boelman; Dragos A Nita; Ayako Ochi; Cristina Y Go; O Carter Snead 3rd; James T Rutka; James M Drake; Sylvester Chuang; Hiroshi Otsubo

doi:10.1016/j.clinph.2014.12.005

Spatial relationship between fast and slow components of ictal activities and interictal epileptiform discharges in epileptic spasms

Clin Neurophysiol. 2015 Sep;126(9):1684-91. doi: 10.1016/j.clinph.2014.12.005. Epub 2014 Dec 15.

Authors

Affiliations

¹ Division of Neurology, The Hospital for Sick Children, Toronto, Canada; Department of Child Neurology, Okayama University Hospital, Okayama, Japan.
² Department of Child Neurology, Okayama University Hospital, Okayama, Japan.
³ Division of Neurology, The Hospital for Sick Children, Toronto, Canada; Department of Child Neurology, Seirei Hamamatsu Hospital, Shizuoka, Japan.
⁴ Division of Neurology, The Hospital for Sick Children, Toronto, Canada.
⁵ Division of Neurosurgery, The Hospital for Sick Children, Toronto, Canada.
⁶ Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto, Canada.
⁷ Division of Neurology, The Hospital for Sick Children, Toronto, Canada. Electronic address: hiroshi.otsubo@sickkids.ca.

PMID: 25557960
DOI: 10.1016/j.clinph.2014.12.005

Abstract

Objective: We analyzed the spatial distribution and concordance of fast (>10Hz) and slow (<5Hz) electroencephalogram (EEG) components of ictal activities and interictal epileptiform discharges (IIED) recorded by intracranial video EEG (IVEEG) in children with epileptic spasms (ES).

Methods: We studied eight children with ES, who underwent IVEEG before resective surgery for epilepsy. We quantified the root-mean-square (RMS) amplitude of the fast and slow components of ictal activities during ES and IIED. We compared the concordance between the spatial distributions of the fast and slow components of ES and IIED.

Results: There was a larger concordance between the spatial distributions of the fast and slow components in IIED than in ES (p=0.0206 and 0.0401).

Conclusions: The spatial concordance between the fast and slow EEG components was significantly different between ES and IIED.

Significance: The mechanisms underlying the generation of slow EEG components may differ between ES and IIED. The slow EEG components of ES might indicate an extensive epileptic network involving remote symptomatic zones for ES in either the cortical or subcortical areas. The high spatial concordance between the fast and slow components of IIED suggests the involvement of a local inhibitory process within the epileptic cortex.

Keywords: Epileptic spasms; Fast waves; Interictal epileptiform discharges; Slow waves; Spatial distribution.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adolescent
Cerebral Cortex / physiopathology*
Child
Child, Preschool
Electroencephalography / methods*
Epilepsy / diagnosis*
Epilepsy / physiopathology*
Female
Humans
Male
Retrospective Studies
Time Factors