Interictal high frequency oscillations correlating with seizure outcome in patients with widespread epileptic networks in tuberous sclerosis complex

Tohru Okanishi; Tomoyuki Akiyama; Shin Ichi Tanaka; Ellen Mayo; Ayu Mitsutake; Cyrus Boelman; Cristina Go; O. Carter Snead; James Drake; James Rutka; Ayako Ochi; Hiroshi Otsubo

doi:10.1111/epi.12761

Interictal high frequency oscillations correlating with seizure outcome in patients with widespread epileptic networks in tuberous sclerosis complex

Tohru Okanishi, Tomoyuki Akiyama, Shin Ichi Tanaka, Ellen Mayo, Ayu Mitsutake, Cyrus Boelman, Cristina Go, O. Carter Snead, James Drake, James Rutka, Ayako Ochi, Hiroshi Otsubo

Research output: Contribution to journal › Article › peer-review

66 Citations (Scopus)

Abstract

Summary Objective Multiple tubers in patients with tuberous sclerosis complex (TSC) often are responsible for drug-resistant epilepsy. The complexity of the epileptic network formed by multiple tubers complicates localization of the epileptogenic zone that is needed to design a surgical treatment strategy. High frequency oscillations (HFOs) on intracranial video-electroencephalography (IVEEG) may be a valuable surrogate marker for the localization of the epileptogenic zone. The purpose of this study was to test the hypothesis that high occurrence rate (OR) of interictal HFOs can guide the localization of the epileptogenic zone.

Methods We analyzed the OR of interictal HFOs at 80-200 Hz (ripples) and >200 Hz (fast ripples, FRs). We divided OR of interictal HFOs between high and low rates by thresholding. We analyzed the correlation between seizure outcomes using Engel classification and the resection ratio of the seizure onset zone (SOZ), and high-OR HFOs using ordinal logistic regression analysis.

Results We collected 10 patients. The seizure outcomes resulted in Engel classification I in three patients, II in four, III in one, and IV in two. High-OR ripples (5-57 [mean 29] channels, 1-4 [2.8] lobes) and high-OR FRs (9-66 [mean 27] channels, 1-4 [2.6] lobes) were widely distributed. The resection ratio of SOZ did not show statistically significant correlation with the seizure outcome. The resection ratio of high-OR ripples showed statistically significant correlation with the seizure outcome (p = 0.038). The resection ratio of high-OR FRs showed statistically significant correlation with the seizure outcome (p = 0.048).

Significance The multiple extensive zones with high-OR HFOs suggest a complex and widespread epileptic network in patients with TSC. In a subset of TSC patients with drug-resistant epilepsy, resection of cortex with both interictal high-OR FRs and ripples on IVEEG correlated with a good seizure outcome.

Original language	English
Pages (from-to)	1602-1610
Number of pages	9
Journal	Epilepsia
Volume	55
Issue number	10
DOIs	https://doi.org/10.1111/epi.12761
Publication status	Published - Oct 1 2014

Keywords

Complex epileptic network
Epilepsy surgery
Epileptogenesis
High frequency oscillations
Multiple cortical tubers
Potential epileptogenic zone

ASJC Scopus subject areas

Neurology
Clinical Neurology

Access to Document

10.1111/epi.12761

Cite this

@article{c0b57e4b5bcc44a68c5df66fa8803b05,

title = "Interictal high frequency oscillations correlating with seizure outcome in patients with widespread epileptic networks in tuberous sclerosis complex",

abstract = "Summary Objective Multiple tubers in patients with tuberous sclerosis complex (TSC) often are responsible for drug-resistant epilepsy. The complexity of the epileptic network formed by multiple tubers complicates localization of the epileptogenic zone that is needed to design a surgical treatment strategy. High frequency oscillations (HFOs) on intracranial video-electroencephalography (IVEEG) may be a valuable surrogate marker for the localization of the epileptogenic zone. The purpose of this study was to test the hypothesis that high occurrence rate (OR) of interictal HFOs can guide the localization of the epileptogenic zone.Methods We analyzed the OR of interictal HFOs at 80-200 Hz (ripples) and >200 Hz (fast ripples, FRs). We divided OR of interictal HFOs between high and low rates by thresholding. We analyzed the correlation between seizure outcomes using Engel classification and the resection ratio of the seizure onset zone (SOZ), and high-OR HFOs using ordinal logistic regression analysis.Results We collected 10 patients. The seizure outcomes resulted in Engel classification I in three patients, II in four, III in one, and IV in two. High-OR ripples (5-57 [mean 29] channels, 1-4 [2.8] lobes) and high-OR FRs (9-66 [mean 27] channels, 1-4 [2.6] lobes) were widely distributed. The resection ratio of SOZ did not show statistically significant correlation with the seizure outcome. The resection ratio of high-OR ripples showed statistically significant correlation with the seizure outcome (p = 0.038). The resection ratio of high-OR FRs showed statistically significant correlation with the seizure outcome (p = 0.048).Significance The multiple extensive zones with high-OR HFOs suggest a complex and widespread epileptic network in patients with TSC. In a subset of TSC patients with drug-resistant epilepsy, resection of cortex with both interictal high-OR FRs and ripples on IVEEG correlated with a good seizure outcome.",

keywords = "Complex epileptic network, Epilepsy surgery, Epileptogenesis, High frequency oscillations, Multiple cortical tubers, Potential epileptogenic zone",

author = "Tohru Okanishi and Tomoyuki Akiyama and Tanaka, {Shin Ichi} and Ellen Mayo and Ayu Mitsutake and Cyrus Boelman and Cristina Go and Snead, {O. Carter} and James Drake and James Rutka and Ayako Ochi and Hiroshi Otsubo",

year = "2014",

month = oct,

day = "1",

doi = "10.1111/epi.12761",

language = "English",

volume = "55",

pages = "1602--1610",

journal = "Epilepsia",

issn = "0013-9580",

publisher = "Wiley-Blackwell",

number = "10",

}

TY - JOUR

T1 - Interictal high frequency oscillations correlating with seizure outcome in patients with widespread epileptic networks in tuberous sclerosis complex

AU - Okanishi, Tohru

AU - Akiyama, Tomoyuki

AU - Tanaka, Shin Ichi

AU - Mayo, Ellen

AU - Mitsutake, Ayu

AU - Boelman, Cyrus

AU - Go, Cristina

AU - Snead, O. Carter

AU - Drake, James

AU - Rutka, James

AU - Ochi, Ayako

AU - Otsubo, Hiroshi

PY - 2014/10/1

Y1 - 2014/10/1

N2 - Summary Objective Multiple tubers in patients with tuberous sclerosis complex (TSC) often are responsible for drug-resistant epilepsy. The complexity of the epileptic network formed by multiple tubers complicates localization of the epileptogenic zone that is needed to design a surgical treatment strategy. High frequency oscillations (HFOs) on intracranial video-electroencephalography (IVEEG) may be a valuable surrogate marker for the localization of the epileptogenic zone. The purpose of this study was to test the hypothesis that high occurrence rate (OR) of interictal HFOs can guide the localization of the epileptogenic zone.Methods We analyzed the OR of interictal HFOs at 80-200 Hz (ripples) and >200 Hz (fast ripples, FRs). We divided OR of interictal HFOs between high and low rates by thresholding. We analyzed the correlation between seizure outcomes using Engel classification and the resection ratio of the seizure onset zone (SOZ), and high-OR HFOs using ordinal logistic regression analysis.Results We collected 10 patients. The seizure outcomes resulted in Engel classification I in three patients, II in four, III in one, and IV in two. High-OR ripples (5-57 [mean 29] channels, 1-4 [2.8] lobes) and high-OR FRs (9-66 [mean 27] channels, 1-4 [2.6] lobes) were widely distributed. The resection ratio of SOZ did not show statistically significant correlation with the seizure outcome. The resection ratio of high-OR ripples showed statistically significant correlation with the seizure outcome (p = 0.038). The resection ratio of high-OR FRs showed statistically significant correlation with the seizure outcome (p = 0.048).Significance The multiple extensive zones with high-OR HFOs suggest a complex and widespread epileptic network in patients with TSC. In a subset of TSC patients with drug-resistant epilepsy, resection of cortex with both interictal high-OR FRs and ripples on IVEEG correlated with a good seizure outcome.

AB - Summary Objective Multiple tubers in patients with tuberous sclerosis complex (TSC) often are responsible for drug-resistant epilepsy. The complexity of the epileptic network formed by multiple tubers complicates localization of the epileptogenic zone that is needed to design a surgical treatment strategy. High frequency oscillations (HFOs) on intracranial video-electroencephalography (IVEEG) may be a valuable surrogate marker for the localization of the epileptogenic zone. The purpose of this study was to test the hypothesis that high occurrence rate (OR) of interictal HFOs can guide the localization of the epileptogenic zone.Methods We analyzed the OR of interictal HFOs at 80-200 Hz (ripples) and >200 Hz (fast ripples, FRs). We divided OR of interictal HFOs between high and low rates by thresholding. We analyzed the correlation between seizure outcomes using Engel classification and the resection ratio of the seizure onset zone (SOZ), and high-OR HFOs using ordinal logistic regression analysis.Results We collected 10 patients. The seizure outcomes resulted in Engel classification I in three patients, II in four, III in one, and IV in two. High-OR ripples (5-57 [mean 29] channels, 1-4 [2.8] lobes) and high-OR FRs (9-66 [mean 27] channels, 1-4 [2.6] lobes) were widely distributed. The resection ratio of SOZ did not show statistically significant correlation with the seizure outcome. The resection ratio of high-OR ripples showed statistically significant correlation with the seizure outcome (p = 0.038). The resection ratio of high-OR FRs showed statistically significant correlation with the seizure outcome (p = 0.048).Significance The multiple extensive zones with high-OR HFOs suggest a complex and widespread epileptic network in patients with TSC. In a subset of TSC patients with drug-resistant epilepsy, resection of cortex with both interictal high-OR FRs and ripples on IVEEG correlated with a good seizure outcome.

KW - Complex epileptic network

KW - Epilepsy surgery

KW - Epileptogenesis

KW - High frequency oscillations

KW - Multiple cortical tubers

KW - Potential epileptogenic zone

UR - http://www.scopus.com/inward/record.url?scp=84911487538&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84911487538&partnerID=8YFLogxK

U2 - 10.1111/epi.12761

DO - 10.1111/epi.12761

M3 - Article

C2 - 25196064

AN - SCOPUS:84911487538

SN - 0013-9580

VL - 55

SP - 1602

EP - 1610

JO - Epilepsia

JF - Epilepsia

IS - 10

ER -

Interictal high frequency oscillations correlating with seizure outcome in patients with widespread epileptic networks in tuberous sclerosis complex

Abstract

Keywords

ASJC Scopus subject areas

Access to Document

Other files and links

Fingerprint

Cite this