Focal EpilepsyTRICSNCT06453759
Thalamic Recordings in Children Undergoing SEEG
A study testing Additional electrodes into bilateral anterior, centromedian and pulvinar thalamic nuclei in people with Focal Epilepsy, run by Great Ormond Street Hospital for Children NHS Foundation Trust at 1 site in United Kingdom.
Trial summary
Stereoelectroencephalography (SEEG) forms a key part of the pre-surgical evaluation in children who may be candidates for epilepsy surgery. It can help delineate the location of the putative epileptogenic zone, guiding further treatments including resective, disconnective and ablative epilepsy surgery techniques. Read more about this study
- Who is it for?
- Ages 2 to 20 years
- Conditions the study is for
- Focal Epilepsy
- What is being tested?
- Additional electrodes into bilateral anterior, centromedian and pulvinar thalamic nuclei
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 30 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- 1 Sep 2025to Dec 2028
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 2 to 20 years
- All sexes
- No healthy volunteers
- Child, Adult
Who may be able to join
- All children undergoing SEEG as part of their pre-surgical evaluation at GOSH
- Participants/parents/legal guardian provide informed consent for inclusion
Who cannot join
- 1) Lack of informed consent
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Martin Tisdall, MD contact
United Kingdom1 site, 1 recruiting
- Recruiting
Great Ormond Street Hospital for Children
London, WC1N 3JH
Aswin Chari, PhD, 07726780817, aswin.chari.18@ucl.ac.uk
About this study
Stereoelectroencephalography (SEEG) forms a key part of the pre-surgical evaluation in children who may be candidates for epilepsy surgery. It can help delineate the location of the putative epileptogenic zone, guiding further treatments including resective, disconnective and ablative epilepsy surgery techniques. However, less than 35% of children undergoing SEEG end up becoming seizure free following further treatment.
Open and closed loop stimulation of thalamic nuclei via deep brain stimulation (DBS) and responsive neurostimulation (RNS) are emerging treatment options for epilepsy. Thalamic target nuclei vary between studies and there are currently no gold standard personalised methods for choosing a target. This stems from the limited systematic neurophysiological recordings from thalamic nuclei; investigators currently do not understand the ictal and interictal thalamic signatures of involvement in epilepsy and do not understand how functional connectivity can be altered within and between patients.
Read more
In this prospective study, the investigators aim to recruit 30 patients undergoing SEEG as part of their pre-surgical evaluation for drug resistant epilepsy at Great Ormond Street Hospital over a period of 3 years. Once recruited, the investigators will target 3 nuclei bilaterally in each patient - the anterior, centromedian and pulvinar nuclei - using additional SEEG electrodes. Following clinical recording, the investigators will conduct two stimulation experiments, the first using single pulse electrical stimulation to measure effective connectivity between the thalamus and cortical regions and the second to study the effects of simulated DBS currents on cortical local field potential signatures.
This study will lay the foundation for a personalised approach to thalamic neuromodulation for drug-resistant epilepsy by identifying neurophysiological biomarkers of thalamic involvement in epilepsy, paving the way for closed loop neuromodulation strategies that aim to optimise response using these biomarkers.
- Conditions
- Focal Epilepsy
- Being tested
- Additional electrodes into bilateral anterior, centromedian and pulvinar thalamic nuclei
- Medical subject headings
- Epilepsies, Partial
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Additional electrodes into bilateral anterior, centromedian and pulvinar thalamic nucleiProcedure or surgery
The centromedian, anterior and pulvinar nuclei on each side will be chosen as target for new electrodes; up to 6 additional electrodes may be added but, where possible, existing electrode trajectories will be extended to facilitate recording.
At the beginning of the recording process, usually within the first 24-48 hours of implantation, we will conduct 2 study-specific stimulation experiments:
- Single pulse electrical stimulation (SPES):
- N-of-1 trials of simulated DBS: We will simulate high (130Hz) and low (6Hz) frequency DBS currents from each pair of thalamic nuclei (always bilateral) and record spontaneous interictal neuronal activity in all other cortical contacts for 15 minutes. We will also record SPES from each of the cortical contacts.
| Study group | Role | What they receive |
|---|---|---|
| Thalamic SEEG | Experimental | The centromedian, anterior and pulvinar nuclei on each side will be chosen as target for new electrodes. Receives: Procedure: Additional electrodes into bilateral anterior, centromedian and pulvinar thalamic nuclei |
What is being measured
The primary outcome is the main question the study is designed to answer.
Ictal thalamic involvement
Experienced neurophysiologists will assess, during ictal activity, whether each of the nuclei are involved in the seizure and, if so, the latency between first cortical contact onset and thalamic nucleus onset.
Measured: Hospital discharge (maximum one month from SEEG implantation)
Epileptogenicity index
We will quantify ictal involvement by measuring the epileptogenicity index in each nucleus.
Measured: Hospital discharge (maximum one month from SEEG implantation)
Interictal power distribution
To assess interictal signatures, we will assess power at different frequencies in the nuclei using the 'fitting oscillations \& one over f' (FOOOF) method.
Measured: Hospital discharge (maximum one month from SEEG implantation)
Single pulse electrical stimulation (SPES):
We will systematically conduct SPES from all cortical and thalamic contacts and record responses in all other contacts. This measures the effective connectivity.
Measured: Hospital discharge (maximum one month from SEEG implantation)
Secondary outcomes (1)
Incidence of bleeding
Radiological evidence of bleeding or clinically new neurological symptoms during SEEG implantation
Measured: Hospital discharge (maximum one month from SEEG implantation)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted12 Jun 2024
- Study start1 Sep 2025
- Primary completionAug 2028 (estimated)
- Study completionDec 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Focal EpilepsyStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 30 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Great Ormond Street Hospital for Children NHS Foundation Trust
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06453759
- Sponsor's protocol ID
- 23BI31
- Acronym
- TRICS
- Status last verified
- Jan 2026
- First submitted
- 24 May 2024
- Last updated
- 2 Feb 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided: IPD may not be allowed to be shared by our ethical approvals. We may make anonymised data available based on restrictions of ethical approvals.
Study at a glance
From the registry record, last updated by the sponsor on 2 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Thalamic Recordings in Children Undergoing SEEG
- ClinicalTrials.gov ID
- NCT06453759
- Acronym / sponsor ID
- TRICS / 23BI31
- Conditions
- Focal Epilepsy
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 30 participants (estimated)
- Lead sponsor
- Great Ormond Street Hospital for Children NHS Foundation TrustUniversity, hospital or other
- Study start
- 1 Sep 2025 (actual)
- Primary completion
- Aug 2028 (estimated)
- Study completion
- Dec 2028 (estimated)
- First posted
- 12 Jun 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Stereoelectroencephalography (SEEG) forms a key part of the pre-surgical evaluation in children who may be candidates for epilepsy surgery. It can help delineate the location of the putative epileptogenic zone, guiding further treatments including resective, disconnective and ablative epilepsy surgery techniques. However, less than 35% of children undergoing SEEG end up becoming seizure free following further treatment.
Open and closed loop stimulation of thalamic nuclei via deep brain stimulation (DBS) and responsive neurostimulation (RNS) are emerging treatment options for epilepsy. Thalamic target nuclei vary between studies and there are currently no gold standard personalised methods for choosing a target. This stems from the limited systematic neurophysiological recordings from thalamic nuclei; investigators currently do not understand the ictal and interictal thalamic signatures of involvement in epilepsy and do not understand how functional connectivity can be altered within and between patients.
In this prospective study, the investigators aim to recruit 30 patients undergoing SEEG as part of their pre-surgical evaluation for drug resistant epilepsy at Great Ormond Street Hospital over a period of 3 years. Once recruited, the investigators will target 3 nuclei bilaterally in each patient - the anterior, centromedian and pulvinar nuclei - using additional SEEG electrodes. Following clinical recording, the investigators will conduct two stimulation experiments, the first using single pulse electrical stimulation to measure effective connectivity between the thalamus and cortical regions and the second to study the effects of simulated DBS currents on cortical local field potential signatures.
This study will lay the foundation for a personalised approach to thalamic neuromodulation for drug-resistant epilepsy by identifying neurophysiological biomarkers of thalamic involvement in epilepsy, paving the way for closed loop neuromodulation strategies that aim to optimise response using these biomarkers.
Study design
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Thalamic SEEG | Experimental | Procedure: Additional electrodes into bilateral anterior, centromedian and pulvinar thalamic nucleiThe centromedian, anterior and pulvinar nuclei on each side will be chosen as target for new electrodes. |
Who may qualify
- Ages
- 2 to 20 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult
Key inclusion criteria (2 listed)
- All children undergoing SEEG as part of their pre-surgical evaluation at GOSH
- Participants/parents/legal guardian provide informed consent for inclusion
Key exclusion criteria (1 listed)
- 1) Lack of informed consent
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Additional electrodes into bilateral anterior, centromedian and pulvinar thalamic nucleiThe centromedian, anterior and pulvinar nuclei on each side will be chosen as target for new electrodes; up to 6 additional electrodes may be added but, where possible, existing electrode trajectories will be extended to facilitate recording. At the beginning of the recording process, usually within the first 24-48 hours of implantation, we will conduct 2 study-specific stimulation experiments: 1. Single pulse electrical stimulation (SPES): 2. N-of-1 trials of simulated DBS: We will simulate high (130Hz) and low (6Hz) frequency DBS currents from each pair of thalamic nuclei (always bilateral) and record spontaneous interictal neuronal activity in all other cortical contacts for 15 minutes. We will also record SPES from each of the cortical contacts. | Procedure or surgery | Thalamic SEEG |
Primary outcome
Ictal thalamic involvement
Time frame: Hospital discharge (maximum one month from SEEG implantation)
Experienced neurophysiologists will assess, during ictal activity, whether each of the nuclei are involved in the seizure and, if so, the latency between first cortical contact onset and thalamic nucleus onset.
Epileptogenicity index
Time frame: Hospital discharge (maximum one month from SEEG implantation)
We will quantify ictal involvement by measuring the epileptogenicity index in each nucleus.
Interictal power distribution
Time frame: Hospital discharge (maximum one month from SEEG implantation)
To assess interictal signatures, we will assess power at different frequencies in the nuclei using the 'fitting oscillations \& one over f' (FOOOF) method.
Single pulse electrical stimulation (SPES):
Time frame: Hospital discharge (maximum one month from SEEG implantation)
We will systematically conduct SPES from all cortical and thalamic contacts and record responses in all other contacts. This measures the effective connectivity.
1 secondary outcome
Incidence of bleeding
Time frame: Hospital discharge (maximum one month from SEEG implantation)
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 2 Feb 2026.
- Individual participant dataSharing planned: Undecided. IPD may not be allowed to be shared by our ethical approvals. We may make anonymised data available based on restrictions of ethical approvals.
Related trials for Focal Epilepsy
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Study Evaluating the Efficacy and Safety of RAP-219 in Adult Participants With Focal Seizures FOCUS-1
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RecruitingObservational study
Surgery as a Treatment for Medically Intractable Epilepsy
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RecruitingObservational study
Noninvasive Pre-surgical Evaluation of Patients With Focal Epilepsy and Establishment of a Normative Imaging Database
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Martin Tisdall, MD contact
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Additional electrodes into bilateral anterior, centromedian and pulvinar thalamic nuclei in people with Focal Epilepsy, run by Great Ormond Street Hospital for Children NHS Foundation Trust at 1 site in United Kingdom.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 1 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 2 Feb 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Aswin Chari, PhD (07726780817, aswin.chari.18@ucl.ac.uk), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Ictal thalamic involvement (time frame: Hospital discharge (maximum one month from SEEG implantation)). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 2 Feb 2026.