Skip to content
DraconiticResearch
Search Sources API
203,234 studies31 sourcesUpdated 36 min ago
Peer-reviewedCC BY 4.0Journal of Clinical Neurophysiology

Consistency of Ictal Epileptogenic Foci in Children With Tuberous Sclerosis Complex and Its Clinical Predictors

  • Carmen Stevering1
  • Willem Otte1
  • Frans Leijten2
  • Mireille Bourez3
  • Louis Wagner4,5
  • Kees Braun1
  • Floor E. Jansen1
5 affiliations
  1. 1Department of Paediatric Neurology, Brain Center UMC Utrecht, Utrecht, the Netherlands
  2. 2Department of Neurology, Brain Center UMC Utrecht, Utrecht, the Netherlands
  3. 3Stichting Epilepsie Instellingen Nederland, Heemstede, the Netherlands
  4. 4Academic Center of Epileptology Kempenhaeghe/Maastricht University Medical Center, Maastricht, the Netherlands; and
  5. 5Academic Center of Epileptology Kempenhaeghe/Maastricht University Medical Center, Heeze, the Netherlands.
Read full textDOICite

Abstract

Purpose:: The course of epilepsy in patients with tuberous sclerosis complex (TSC) is highly variable. Consistency of the epileptogenic zone is considered important in presurgical evaluation. The authors aimed to (1) assess consistency of ictal epileptogenic foci over time in patients with TSC, (2) evaluate concordance between interictal epileptiform abnormalities and ictal epileptogenic foci, and (3) identify determinants of ictal consistency.

Methods:: This single-center retrospective, observational study included children with definite TSC and epilepsy with ≥2 ictal presurgical EEGs with an interval ≥1 year. In all EEGs, the regional localization of interictal and ictal epileptiform abnormalities was scored based on the EEG reports. All ictal epileptogenic foci were classified with an “ictal focus consistency score,” according to one of the following subcategories: “single focus, consistent,” “from unclear localization/diffuse or generalized to unifocal,” “≥2 or more foci, each consistent,” “≥2 foci of which at least one is consistent,” “starting multifocal but at last EEG unifocal,” and “multifocal changing otherwise.” The primary end point was unifocal or multifocal consistency of ictal foci. The secondary end point was concordance between ictal epileptogenic foci and localization of interictal epileptiform abnormalities. The third end point involved an exploratory assessment of potential determinants of ictal consistency, including TSC variant, age at epilepsy onset, epileptic spasms, multiple seizure types, interictal multifocality, and tuber load.

Results:: The authors included 45 patients with TSC with a median of 3 (interquartile range 2–4) ictal and 8 (interquartile range 5–10) interictal EEGs per patient. Median time between first and last ictal EEG was 28.4 months (19.0–60.3). Ictal foci were consistent over time in 11 patients (24.4%), of whom 9 had 1 consistent ictal focus. Nine other patients had a single consistent ictal focus on the first EEGs, but developed a second focus at the median age of 67.7 months. Of the 13 patients who later underwent surgery, 3 had a single focus, and only 2 of 13 had consistent ictal EEGs. The same three patients with a single focus over time were part of the seven postoperative seizure-free patients. All six nonseizure-free children had ictal multifocality. Interictal and ictal epileptogenic foci were discordant in 42 of 45 patients (93.3%). Exploratory analyses of potential determinants of ictal consistency suggested a negative association with interictal multifocality (risk ratio 0.32, 95% confidence interval 0.06–0.97, p = 0.04), which was not significant after adjustment for monitoring duration.

Conclusions:: Ictal epileptogenic foci are consistent in only 25% of the patients with TSC. Interictal epileptogenic foci are often discordant with ictal foci. This instability in the ictal epileptogenic focus might be explained by the presence of larger epileptogenic networks in TSC that undergo evolution over time.

Significance:: The findings in this study could have important implications for presurgical evaluation in patients with TSC and might help to understand the cause of (late) surgical failure.

Related

  1. Amyloid-Independent Elevation of Plasma phosphorylated tau-217 Tracks Neurodegenerative Risk in Tuberous Sclerosis Complex: Implications for mTOR-Targeted Intervention
    J. Baumel, M. Lutz, C. Ding +6
    medRxivPreprintAll rights reservedFull textNeurologymedRxiv
  2. Subependymal Giant Cell Astrocytoma Mimicking Recurrent Ependymoma: Imaging Clues to the Diagnosis of Tuberous Sclerosis Complex
    Abdelilah Bouymajjan, Asmae Oulad Amar, El Mahdi Choukri +2
    CureusPeer-reviewedCC BYFull textMedical imaging & radiologyEurope PMCEurope PMCPMC
  3. Interventricular septal fat-containing mass most consistent with cardiac lipoma in an adult with tuberous sclerosis complex.
    Saubhagya Dhakal, Paulo Savoia, Nikahat Yasmine +1
    Radiology case reportsPeer-reviewedCC BYFull textPhysiologyEurope PMC
  4. mTORC1 drives cell-autonomous astrocyte reactivity in tuberous sclerosis
    Thomas L. Li, John D. Blair, Taesun Yoo +4
    NaturePeer-reviewedCC BY12 citedHuman geneticsPhysiologyOpenAlex
  5. Structural validity and internal consistency of the Client Satisfaction Questionnaire-8 among parents of children with ADHD: a cross-sectional study
    Cecilie Katrine Utheim Grønvik, Ingunn Mundal, Petter Laake +1
    BMJ OpenPeer-reviewedCC BY-NC 4.0Full textPsychiatry & mental healthCrossrefEurope PMC

Cite

BibTeXRIS
BibTeX
@article{stevering2026consistency,
  title = {{Consistency of Ictal Epileptogenic Foci in Children With Tuberous Sclerosis Complex and Its Clinical Predictors}},
  author = {Carmen Stevering and Willem Otte and Frans Leijten and Mireille Bourez and Louis Wagner and Kees Braun and Floor E. Jansen},
  journal = {Journal of Clinical Neurophysiology},
  year = {2026},
  month = may,
  doi = {10.1097/wnp.0000000000001260},
  url = {https://doi.org/10.1097/wnp.0000000000001260},
  note = {CC BY 4.0},
}
RIS
TY  - JOUR
TI  - Consistency of Ictal Epileptogenic Foci in Children With Tuberous Sclerosis Complex and Its Clinical Predictors
AU  - Carmen Stevering
AU  - Willem Otte
AU  - Frans Leijten
AU  - Mireille Bourez
AU  - Louis Wagner
AU  - Kees Braun
AU  - Floor E. Jansen
PY  - 2026
DA  - 2026/05/20
JO  - Journal of Clinical Neurophysiology
DO  - 10.1097/wnp.0000000000001260
UR  - https://doi.org/10.1097/wnp.0000000000001260
AB  - Purpose:: The course of epilepsy in patients with tuberous sclerosis complex (TSC) is highly variable. Consistency of the epileptogenic zone is considered important in presurgical evaluation. The authors aimed to (1) assess consistency of ictal epileptogenic foci over time in patients with TSC, (2) evaluate concordance between interictal epileptiform abnormalities and ictal epileptogenic foci, and (3) identify determinants of ictal consistency.  Methods:: This single-center retrospective, observational study included children with definite TSC and epilepsy with ≥2 ictal presurgical EEGs with an interval ≥1 year. In all EEGs, the regional localization of interictal and ictal epileptiform abnormalities was scored based on the EEG reports. All ictal epileptogenic foci were classified with an “ictal focus consistency score,” according to one of the following subcategories: “single focus, consistent,” “from unclear localization/diffuse or generalized to unifocal,” “≥2 or more foci, each consistent,” “≥2 foci of which at least one is consistent,” “starting multifocal but at last EEG unifocal,” and “multifocal changing otherwise.” The primary end point was unifocal or multifocal consistency of ictal foci. The secondary end point was concordance between ictal epileptogenic foci and localization of interictal epileptiform abnormalities. The third end point involved an exploratory assessment of potential determinants of ictal consistency, including TSC variant, age at epilepsy onset, epileptic spasms, multiple seizure types, interictal multifocality, and tuber load.  Results:: The authors included 45 patients with TSC with a median of 3 (interquartile range 2–4) ictal and 8 (interquartile range 5–10) interictal EEGs per patient. Median time between first and last ictal EEG was 28.4 months (19.0–60.3). Ictal foci were consistent over time in 11 patients (24.4%), of whom 9 had 1 consistent ictal focus. Nine other patients had a single consistent ictal focus on the first EEGs, but developed a second focus at the median age of 67.7 months. Of the 13 patients who later underwent surgery, 3 had a single focus, and only 2 of 13 had consistent ictal EEGs. The same three patients with a single focus over time were part of the seven postoperative seizure-free patients. All six nonseizure-free children had ictal multifocality. Interictal and ictal epileptogenic foci were discordant in 42 of 45 patients (93.3%). Exploratory analyses of potential determinants of ictal consistency suggested a negative association with interictal multifocality (risk ratio 0.32, 95% confidence interval 0.06–0.97, p = 0.04), which was not significant after adjustment for monitoring duration.  Conclusions:: Ictal epileptogenic foci are consistent in only 25% of the patients with TSC. Interictal epileptogenic foci are often discordant with ictal foci. This instability in the ictal epileptogenic focus might be explained by the presence of larger epileptogenic networks in TSC that undergo evolution over time.  Significance:: The findings in this study could have important implications for presurgical evaluation in patients with TSC and might help to understand the cause of (late) surgical failure.
SN  - 0736-0258
SN  - 1537-1603
ER  -