Characteristics of ictal thalamic EEG in pediatric-onset neocortical focal epilepsy
Benjamin Edmonds1, Makoto Miyakoshi2,3,4, Luigi Gianmaria Remore5
1Division of Pediatric Neurology, Department of Pediatrics, UCLA Mattel Children's Hospital, David Geffen School of Medicine, Los Angeles, CA, USA.
Insights
Ictal electroencephalography (EEG) changes in the centromedian (CM) and anterior nucleus (AN) of the thalamus were consistently detected during neocortical seizures. This suggests potential for thalamic closed-loop systems to detect and manage seizure activity in epilepsy.
Area of Science:
- Neuroscience
- Epileptology
- Clinical Neurophysiology
Background:
- Neocortical epilepsy is a common neurological disorder characterized by recurrent seizures originating from the cerebral cortex.
- The thalamus, particularly the centromedian (CM) and anterior nucleus (AN), plays a role in seizure generation and propagation.
- Stereoelectroencephalography (SEEG) allows for detailed investigation of brain activity during seizures.
Approach:
- This study analyzed 40 habitual seizures in nine pediatric patients with drug-resistant neocortical epilepsy using SEEG with thalamic coverage.
- Both visual and quantitative analyses were employed to assess ictal EEG signals in the cortex and thalamus.
- Measurements included amplitude and cortico-thalamic latencies of broadband frequencies at ictal onset.
Key Points:
- Ictal EEG changes were consistently detected in the CM and AN nuclei within 400ms of seizure onset in 95% of cases.
- Low-voltage fast activity was the most common ictal pattern observed.
- Quantitative analysis revealed consistent power changes across frequency bands, with variable latencies, and no significant difference between CM and AN detection.
Conclusions:
- Ictal EEG changes are consistently observed in the CM and AN of the thalamus during neocortical seizures.
- These findings support the feasibility of utilizing thalamic closed-loop systems for detecting and modulating seizure activity in neocortical epilepsy.
- Responsive neurostimulation (RNS) targeting the thalamus showed promise in patients with consistent SEEG findings.
Objective:
To characterize ictal EEG change in the centromedian (CM) and anterior nucleus (AN) of the thalamus, using stereoelectroencephalography (SEEG) recordings.
Methods:
Forty habitual seizures were analyzed in nine patients with pediatric-onset neocortical drug-resistant epilepsy who underwent SEEG (age 2-25 y) with thalamic coverage. Both visual and quantitative analysis was used to evaluate ictal EEG signal in the cortex and thalamus. The amplitude and cortico-thalamic latencies of broadband frequencies at ictal onset were measured.
Results:
Visual analysis demonstrated consistent detection of ictal EEG changes in both the CM nucleus and AN nucleus with latency to thalamic ictal EEG changes of less than 400ms in 95% of seizures, with low-voltage fast activity being the most common ictal pattern. Quantitative broadband amplitude analysis showed consistent power changes across the frequency bands, corresponding to ictal EEG onset, while while ictal EEG latency was variable from -18.0 seconds to 13.2 seconds. There was no significant difference between detection of CM and AN ictal activity on visual or amplitude analysis. Four patients with subsequent thalamic responsive neurostimulation (RNS) demonstrated ictal EEG changes consistent with SEEG findings.
Conclusions:
Ictal EEG changes were consistently seen at the CM and AN of the thalamus during neocortical seizures.
Significance:
It may be feasible to use a closed-loop system in the thalamus to detect and modulate seizure activity for neocortical epilepsy.
More Related Videos
09:57Author Spotlight: Advancing Pediatric Epilepsy Surgery in Children Through Novel Biomarkers and Enhanced Localization
Published on: September 20, 2024
09:00Investigating the Function of Deep Cortical and Subcortical Structures Using Stereotactic Electroencephalography: Lessons from the Anterior Cingulate Cortex
Published on: April 15, 2015
