scholarly journals Role of High-Frequency Oscillation in Locating an Epileptogenic Zone for Radiofrequency Thermocoagulation

2021 ◽  
Vol 15 ◽  
Author(s):  
Xin Xu ◽  
Xingguang Yu ◽  
Guixia Kang ◽  
Zhiqi Mao ◽  
Zhiqiang Cui ◽  
...  
Keyword(s):  
High Frequency ◽  
Low Voltage ◽  
Focal Epilepsy ◽  
High Frequency Oscillation ◽  
Epileptogenic Zone ◽  
Long Term Effects ◽  
Frequency Oscillation ◽  
Radiofrequency Thermocoagulation ◽  
Antiepileptic Medication ◽  
Nodular Heterotopia

Radiofrequency thermocoagulation (RFTC) has been proposed as a first-line surgical treatment option for patients with drug-resistant focal epilepsy (DRE) that is associated with gray matter nodular heterotopia (GMNH). Excellent results on seizures have been reported following unilateral RFTC performed on ictal high-frequency-discharge, fast-rhythm, and low-voltage initiation areas. Complex cases (GMNH plus other malformations of cortical development) do not have good outcomes with RFTC. Yet, there is little research studying the effect of high-frequency oscillation in locating epileptogenic zones for thermocoagulation on unilateral, DRE with bilateral GMNH. We present a case of DRE with bilateral GMNH, treated using RFTC on unilateral GMNH and the overlying cortex, guided by stereotactic electroencephalogram (SEGG), and followed up for 69 months. Twenty-four-hour EGG recordings, seizure frequency, post-RFTC MRI, and neuropsychological tests were performed once yearly. To date, this patient is seizure-free, the electroencephalogram is normal, neuropsychological problems have not been found, and the trace of RFTC has been clearly identified on MRI. His dosage of antiepileptic medication has, furthermore, been significantly reduced. It is concluded that RFTC on unilateral DRE with bilateral GMNH may achieve good long-term effects, lasting up to, and perhaps longer than, 69 months. Ictal high-frequency oscillation (fast ripple) inside the heterotopia and the overlying cortex may be the key to this successful effect.

scholarly journals Distinct EEG seizure patterns reflect different seizure generation mechanisms

2015 ◽  
Vol 113 (7) ◽  
pp. 2840-2844 ◽  
Author(s):  
Pariya Salami ◽  
Maxime Lévesque ◽  
Jean Gotman ◽  
Massimo Avoli
Keyword(s):  
High Frequency ◽  
Channel Blocker ◽  
Seizure Activity ◽  
Low Voltage ◽  
High Frequency Oscillation ◽  
Seizure Onset ◽  
Frequency Oscillation ◽  
Oscillation Analysis ◽  
Pilocarpine Model ◽  
Generation Mechanisms

Low-voltage fast (LVF)- and hypersynchronous (HYP)-seizure onset patterns can be recognized in the EEG of epileptic animals and patients with temporal lobe epilepsy. Ripples (80–200 Hz) and fast ripples (250–500 Hz) have been linked to each pattern, with ripples predominating during LVF seizures and fast ripples predominating during HYP seizures in the rat pilocarpine model. This evidence led us to hypothesize that these two seizure-onset patterns reflect the contribution of neural networks with distinct transmitter signaling characteristics. Here, we tested this hypothesis by analyzing the seizure activity induced with the K+ channel blocker 4-aminopyridine (4AP, 4–5 mg/kg ip), which enhances both glutamatergic and GABAergic transmission, or the GABAA receptor antagonist picrotoxin (3–5 mg/kg ip); rats were implanted with electrodes in the hippocampus, the entorhinal cortex, and the subiculum. We found that LVF onset occurred in 82% of 4AP-induced seizures whereas seizures after picrotoxin were always HYP. In addition, high-frequency oscillation analysis revealed that 4AP-induced LVF seizures were associated with higher ripple rates compared with fast ripples ( P < 0.05), whereas picrotoxin-induced seizures contained higher rates of fast ripples compared with ripples ( P < 0.05). These results support the hypothesis that two distinct patterns of seizure onset result from different pathophysiological mechanisms.

scholarly journals Localization of the Epileptogenic Zone by Multimodal Neuroimaging and High-Frequency Oscillation

2021 ◽  
Vol 15 ◽  
Author(s):  
Xiaonan Li ◽  
Tao Yu ◽  
Zhiwei Ren ◽  
Xueyuan Wang ◽  
Jiaqing Yan ◽  
...  
Keyword(s):  
Surgical Outcome ◽  
High Frequency ◽  
Refractory Epilepsy ◽  
Automated Analysis ◽  
Diagnostic Value ◽  
High Frequency Oscillation ◽  
Epileptogenic Zone ◽  
Frequency Oscillation ◽  
Traditional Methods ◽  
Intracranial Electrodes

Accurate localization of the epileptogenic zone (EZ) is a key factor to obtain good surgical outcome for refractory epilepsy patients. However, no technique, so far, can precisely locate the EZ, and there are barely any reports on the combined application of multiple technologies to improve the localization accuracy of the EZ. In this study, we aimed to explore the use of a multimodal method combining PET-MRI, fluid and white matter suppression (FLAWS)—a novel MRI sequence, and high-frequency oscillation (HFO) automated analysis to delineate EZ. We retrospectively collected 15 patients with refractory epilepsy who underwent surgery and used the above three methods to detect abnormal brain areas of all patients. We compared the PET-MRI, FLAWS, and HFO results with traditional methods to evaluate their diagnostic value. The sensitivities, specificities of locating the EZ, and marking extent removed versus not removed [RatioChann(ev)] of each method were compared with surgical outcome. We also tested the possibility of using different combinations to locate the EZ. The marked areas in every patient established using each method were also compared to determine the correlations among the three methods. The results showed that PET-MRI, FLAWS, and HFOs can provide more information about potential epileptic areas than traditional methods. When detecting the EZs, the sensitivities of PET-MRI, FLAWS, and HFOs were 68.75, 53.85, and 87.50%, and the specificities were 80.00, 33.33, and 100.00%. The RatioChann(ev) of HFO-marked contacts was significantly higher in patients with good outcome than those with poor outcome (p&lt; 0.05). When intracranial electrodes covered all the abnormal areas indicated by neuroimaging with the overlapping EZs being completely removed referred to HFO analysis, patients could reach seizure-free (p &lt; 0.01). The periphery of the lesion marked by neuroimaging may be epileptic, but not every lesion contributes to seizures. Therefore, approaches in multimodality can detect EZ more accurately, and HFO analysis may help in defining real epileptic areas that may be missed in the neuroimaging results. The implantation of intracranial electrodes guided by non-invasive PET-MRI and FLAWS findings as well as HFO analysis would be an optimized multimodal approach for locating EZ.

High‐Frequency Oscillation Networks and Surgical Outcome in Adult Focal Epilepsy

2019 ◽  
Vol 85 (4) ◽  
pp. 485-494 ◽  
Author(s):  
Karina A. González Otárula ◽  
Nicolás von Ellenrieder ◽  
Carolina Cuello‐Oderiz ◽  
François Dubeau ◽  
Jean Gotman
Keyword(s):  
Surgical Outcome ◽  
High Frequency ◽  
Focal Epilepsy ◽  
High Frequency Oscillation ◽  
Frequency Oscillation

Scalp-HFO indexes are biomarkers for the lateralization and localization of the epileptogenic zone in preoperative assessment

2021 ◽  
Vol 126 (4) ◽  
pp. 1148-1158
Author(s):  
Yujiao Yang ◽  
Wei Wang ◽  
Jing Wang ◽  
Mengyang Wang ◽  
Xiaonan Li ◽  
...  
Keyword(s):  
Brain Region ◽  
High Frequency ◽  
Quantitative Assessment ◽  
Preoperative Assessment ◽  
Assessment Method ◽  
Regions Of Interest ◽  
High Frequency Oscillation ◽  
Epileptogenic Zone ◽  
Frequency Oscillation ◽  
The Brain

We proposed the scalp-high-frequency oscillation (HFO) index (HI) as a quantitative assessment method for scalp HFOs to locate the epileptogenic zone (EZ). Our results showed that the HI in regions of interest (ROIs) was significantly higher than in contra-ROIs. Sensitivity and specificity of HI based on ripple rates (n-HI) for EZ localization were 90% and 79.58%, respectively. If the n-HI of the brain region was >1.35, it was more likely to be an epileptogenic region. Clinical application of HIs as an indicator may facilitate localization of the EZ.

High-Frequency Oscillation and Chronic Lung Disease in Very Low Birth Weight Infants

PEDIATRICS ◽  
2001 ◽  
Vol 108 (1) ◽  
pp. 212-214
Author(s):  
J. P. Shenai; ◽  
P. Rimensberger; ◽  
U. Thome ◽  
F. Pohlandt; ◽  
P. Rimensberger
Keyword(s):  
Birth Weight ◽  
Low Birth Weight ◽  
Lung Disease ◽  
Chronic Lung Disease ◽  
High Frequency ◽  
Very Low Birth Weight ◽  
High Frequency Oscillation ◽  
Frequency Oscillation ◽  
Low Birth Weight Infants

scholarly journals A Comprehensive Investigation on High-Frequency Oscillation in DC Microgrid

IEEE Access ◽  
2021 ◽  
pp. 1-1
Author(s):  
Mohammad Habibullah ◽  
Nadarajah Mithulananthan ◽  
Krischonme Bhumkittipich ◽  
Mohammad Amin
Keyword(s):  
High Frequency ◽  
High Frequency Oscillation ◽  
Frequency Oscillation ◽  
Comprehensive Investigation ◽  
Dc Microgrid
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