Prognostic value of scalp EEG ictal patterns in epilepsy surgery of hippocampal sclerosis.

BACKGROUND: Temporal lobe epilepsy associated with hippocampal sclerosis (TLE-HS) is a surgically treatable epileptic syndrome. While the core of pre-surgical evaluations rely on video-EEG, recent studies question the necessity of recorded seizures denying a possible role of ictal EEG in surgical decision. This study aims to retrospectively assess the prognostic value of EEG ictal patterns in TLE-HS, in order to identify which patients need further investigations before offering surgery. METHODS: We included TLE-HS patients who underwent surgery with at least one captured seizure during non-invasive pre-surgical video-EEG recordings. They were classified in "mesial" and "lateral/mixed", according to the ictal EEG patterns, defined by the frequency of the discharge (mesial ≥ 5 Hz, lateral < 5 Hz). Seizure outcome was assessed by Engel's Class. Statistical analyses were performed to evaluate associations between EEG patterns and post-surgical outcomes. RESULTS: Sixty-nine exhibited a mesial pattern, forty- two displayed lateral/mixed patterns. Mesial pattern group had a significantly higher rate of postsurgical seizure freedom (82.7% vs. 28.6%). Gender, age of onset, age at surgery, duration of epilepsy, seizure frequency, and lateralization did not influence the outcome. Mesial pattern significantly correlated with favorable outcomes (p < 0.001), suggesting its potential predictive value. CONCLUSION: This retrospective study proposes ictal EEG patterns as possible predictors of postoperative prognosis in TLE-HS. A mesial pattern correlates with better outcomes, indicating a potentially more circumscribed epileptogenic zone. Patients with lateral/mixed patterns may benefit from additional investigations to delineate the epileptogenic zone. Further studies are warranted to validate and extend these findings.

Predictors of Seizure Recurrence in Women With Idiopathic Generalized Epilepsy Who Switch From Valproate to Another Medication.

BACKGROUND AND OBJECTIVES: To investigate the predictors of seizure recurrence in women of childbearing age with idiopathic generalized epilepsy (IGE) who switched from valproate (VPA) to alternative antiseizure medications (ASMs) and compare the effectiveness of levetiracetam (LEV) and lamotrigine (LTG) as VPA alternatives after switch. METHODS: This multicenter retrospective study included women of childbearing age diagnosed with IGE from 16 epilepsy centers. Study outcomes included worsening or recurrence of generalized tonic-clonic seizure (GTCS) at 12 months and 24 months after the switch from VPA to an alternative ASM. The comparative effectiveness of LEV and LTG as alternative ASM following VPA discontinuation was assessed through inverse probability treatment-weighted (IPTW) Cox regression analysis. RESULTS: We included 426 women with IGE, with a median (interquartile range) age at VPA switch of 24 (19-30) years and a median VPA dosage of 750 (500-1,000) mg/d. The most common reason for VPA switch was teratogenicity concern in 249 women (58.6%), and the most common ASM used in place of VPA was LEV in 197 (46.2%) cases, followed by LTG in 140 (32.9%). GTCS worsening/recurrence occurred in 105 (24.6%) and 139 (32.6%) women at 12 and 24 months, respectively. Catamenial worsening of seizures, higher VPA dosage during switch, multiple seizure types, and shorter duration of GTCS freedom before switch were independent predictors of GTCS recurrence or worsening at 12 months according to mixed multivariable logistic regression analysis. After internal-external validation through 16 independent cohorts, the model showed an area under the curve of 0.71 (95% CI 0.64-0.77). In the subgroup of 337 women who switched to LEV or LTG, IPTW Cox regression analysis showed that LEV was associated with a reduced risk of GTCS worsening or recurrence compared with LTG (adjusted hazard ratio 0.59, 95% CI 0.40-0.87, p = 0.008) during the 24-month follow-up. DISCUSSION: Our findings can have practical implications for optimizing counselling and treatment choices in women of childbearing age with IGE and may help clinicians in making informed treatment decisions in this special population of patients. CLASSIFICATION OF EVIDENCE: This study provides Class III evidence that for women with IGE switching from VPA, LEV was associated with a reduced risk of GTCS worsening or recurrence compared with LTG.

Topiramate ban in women of childbearing potential with idiopathic generalized epilepsy: Does effectiveness offset the teratogenic risks?

Regulatory agencies have recently discouraged the prescription of topiramate (TPM) to women of childbearing potential with epilepsy due to growing evidence of the teratogenic and neurodevelopmental risks associated with its use during pregnancy. It remains, however, unclear whether the use of TPM in this population can be supported to some extent by its high effectiveness. In this multicenter, retrospective, cohort study performed at 22 epilepsy centers, we investigated the comparative effectiveness of TPM and levetiracetam (LEV) given as first-line antiseizure medication in a cohort of women of childbearing potential with idiopathic generalized epilepsy (IGE). A total of 336 participants were included, of whom 24 (7.1%) received TPM and 312 (92.9%) LEV. Women treated with TPM had significantly higher risks of treatment failure and treatment withdrawal and were less likely to achieve seizure freedom at 12 months compared to women treated with LEV. In conclusion, this study highlighted a low tendency among clinicians to use TPM in women of childbearing potential with IGE, anticipating the recently released restrictions on its use. Furthermore, the available data on effectiveness do not appear to support the use of TPM in this population.