Subclinical seizures: The demographic data and scalp video-EEG findings, concordance with the epilepsy type and prognosis.

BACKGROUND: Subclinical seizures(SCSs) are overlooked in clinical practice. This study aims to investigate clinical, electrophysiological features of SCSs detected during video-electroencephalography(EEG) monitorization(VEM), concordance of the epilepsy type and SCSs, and predictors of the concordance. METHODS: The data of drug-resistant epilepsy patients who had undergone video-EEG between 2010 and 2020 were investigated. Ictal activities showing temporospatial evolution lasted ≥ 10 s, without any behavioural changes were considered SCSs. Findings were re-evaluated for ictal localization, lateralization, ictal discharge type, vigilance status, and duration of SCSs to the accompaniment of clinical findings. Additionally, the concordance of epilepsy type and SCSs were analyzed. RESULTS: Fifty-five SCSs were obtained in 24 of 804 patients (2,9 %) who were followed in the VEM unit; the epilepsy type of the patients was temporal in 26 and extratemporal lobe epilepsy in 29 SCSs. Among 55 SCSs recordings, 30 originated from the temporal lobe and 24 from the extratemporal lobe, and seizure localization could not be determined in one. The patients were younger, age at seizure onset was earlier, habitual seizures were more frequent, multiple anti-seizure drug use was higher, seizures more frequently occurred during sleep, cranial MR tended to be abnormal, patients were more likely to have a history of perinatal injury/head trauma, and the concordance of discharge patterns was lower in extratemporal SCSs.The concordance of epilepsy type with localization and lateralization of SCSs was not statistically significant. CONCLUSIONS: SCSs originating from the temporal and extratemporal lobes might show similar characteristics with the epilepsy type, and SCSs might have clinical importance apart from epilepsy surgery.

Changes of oxygen saturation in patients with pure temporal lobe epilepsy.

PURPOSE: Ictal hypoxemia is accepted as one of the mechanisms underlying sudden unexpected death in epilepsy (SUDEP). Although ictal hypoxemia is more common in generalized seizures, it also occurs in focal seizures with or without generalization. In this study, we aimed to show the relationship between clinical and electroencephalographic findings of seizures in patients with temporal lobe epilepsy (TLE) with periictal oxygen saturation. METHODS: The data of 55 adult patients who were hospitalized in the Video EEG Monitoring Unit (VEMU) and operated on for drug-resistant TLE between January 2017 and December 2020 were examined. Forty-five seizures from 21 patients with ictal peripheral arterial saturation information and that were seizure-free for at least a year during the follow-up were included in the study. RESULTS: The median patient age was 28 (IQR 25-39.5) years (women: 9, men: 12). Age at epilepsy onset was negatively correlated with saturation at seizure onset. Moreover, the age at VEMU admission was also negatively correlated with saturation at seizure onset and the lowest levels of saturation. The saturation at the end of the seizures and the lowest saturation measured in the periictal period with generalization of EEG were significantly lower than those without generalization. The onset of ictal EEG with the rhythmic theta pattern was significantly associated with the lowest level of saturation (<90%), postictal generalized electroencephalographic suppression (PGES), and the presence of generalization. CONCLUSION: According to the study, rhythmic ictal theta activity, older age, nocturnal seizure, and generalization in ictal EEG might increase the potential risk of SUDEP. Further studies including a greater number of subjects and different epilepsy syndromes may provide more comprehensive information about potential biomarkers for SUDEP.

Relation between orexin A and epileptic seizures.

INTRODUCTION: One of the unknown mechanisms in epilepsy pathogenesis is the involvement of the hypothalamic neuropeptide orexin. Although the relationship between orexin and sleep has been revealed, its effect in epilepsy has not been fully clarified. In this study, we aimed to show the relationship between orexin A and the seizures that occur during sleep and wakefulness. MATERIAL AND METHODS: This study included 40 patients with drug-resistant focal epilepsy and 37 healthy controls. Night basal orexin (NBO) and morning basal orexin (MBO) levels were measured using enzyme-linked immunosorbent assay in patients and controls. Serum samples were collected from patients after epileptic seizures during sleep and wakefulness. RESULTS: In both patients and controls, MBO levels (median: 1039 pg/mL, interquartile ranges [IQR] (899-1078)) were higher than NBO levels (median 989 pq/mL, IQR (893-1078) (p = 0.02). Basal orexin levels were lower in patients than in controls (p < 0.001). However, while the duration of seizures was shortened in awake seizures, the level of orexin increased (p = 0.007). Additionally, orexin levels after nocturnal seizure were higher in patients who had an ictal electroencephalography onset in the left hemisphere or a lesion in the left temporal lobe (p = 0.02; p = 0.01, respectively). There was no relationship between postictal somnolence and orexin levels. Although there was no significant difference, the level of post-seizure orexin increased compared to the basal values, especially in seizures during sleep. DISCUSSION: The increase in serum orexin levels, especially after seizures, suggests that orexin may be associated with the epileptogenic effect. In further studies, determination of orexin from cerebrospinal fluid (CSF) and correlation of CSF and serum orexin levels may provide more useful information regarding the relationship between orexin and epilepsy.

Evaluation of Thiol Homeostasis in Multiple Sclerosis and Neuromyelitis Optica Spectrum Disorders.

Objectives: The aim of this pilot study was to evaluate dynamic thiol-disulfide homeostasis as a novel oxidative stress parameter in multiple sclerosis (MS), neuromyelitis optica spectrum disorders (NMOSD), and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) to better understand the role of thiol homeostasis in neuroimmunological diseases. Methods: A total of 85 participants were included in this study, consisting of 18 healthy controls, 52 patients diagnosed with MS, seven with NMOSD, and eight with MOGAD. We measured total thiol (-SH+-S-S-) and native thiol (-SH) levels in the serum of all the participants, and in a subset of patients (n = 11), these parameters were investigated in paired cerebrospinal fluid (CSF) and serum samples. Dynamic disulfide concentrations were calculated separately. Finally, we determined if there was any relationship between clinical features and dynamic thiol homeostasis. Results: There was a statistically significant difference between serum and CSF levels of biomarkers of thiol homeostasis. Serum total thiol (317.88 ± 66.04) and native thiol (211.61 ± 44.15) levels were significantly lower in relapsed patients compared to those in remission (368.84 ± 150.36 vs. 222.52 ± 70.59, respectively). Conclusions: Oxidative stress plays a crucial role in the physiopathology of neuroimmunological diseases. Thiol homeostasis may be useful for monitoring disease activity.

Temporal encephaloceles can be missed in patients with refractory temporal lobe epilepsy.

Temporal encephaloceles (TEs) are one of the cause of refractory temporal lobe epilepsy (TLE). We reviewed the neuroimaging and video-electroencephalography (EEG) records of epilepsy patients who underwent temporal lobectomy in our center to investigate frequency of TEs. We retrospectively reevaluated 294 patients who underwent epilepsy surgery in our tertiary epilepsy centre between January 2010 and March 2019 and included 159 patients (78 females, 49 %; 81 males) who had temporal lobectomy. Preoperatively, TEs were reported in 3 of 159 patients (1 female, 2 males). After reevaluation 4 more patients with TEs (1 female, 3 males) were added. The ratio of TE in patients who underwent temporal lobectomy increased from 1.8 % (n=3) to 4,4 % (n=7). The median ages were 18 (range 16-22) versus 10 years (range 5-17) at habitual seizure onset and the median of epilepsy duration was 5 (range 3-15) versus 175 (range 11-25) years between patients with and without TE. Habitual seizure onset age was significantly higher (p =, 007) in the patients with encephalocele and epilepsy duration was shorter (p =, 003) than patients without encephalocele. The ictal EEG records of all patients TE rhythmic delta activity which is suggested neocortical temporal lobe onset seizures. 4 of 7 patients' PET imaging showed temporal lobe hypometabolism compatible with ipsilateral to the TEs. The three patients underwent anterior temporal lobectomy without amygdalohippocampectomy and others had anterior temporal lobectomy with amygdalohippocampectomy. We suggested that there might be some clues for temporal encephalocele, an easily overlooked cause in patients with nonlesional temporal lobe epilepsy.TLE patients with TE had relatively late onset of epilepsy and rhythmic delta activity on ictal EEG. Also, temporal hypometabolism on PET may be a useful key to suspicion of TE.