Coupling between beta band and high frequency oscillations as a clinically useful biomarker for DBS.

Beta hypersynchrony was recently introduced into clinical practice in Parkinson's disease (PD) to identify the best stimulation contacts and for adaptive deep brain stimulation (aDBS) sensing. However, many other oscillopathies accompany the disease, and beta power sensing may not be optimal for all patients. The aim of this work was to study the potential clinical usefulness of beta power phase-amplitude coupling (PAC) with high frequency oscillations (HFOs). Subthalamic nucleus (STN) local field potentials (LFPs) from externalized DBS electrodes were recorded and analyzed in PD patients (n = 19). Beta power and HFOs were evaluated in a resting-state condition; PAC was then studied and compared with the electrode contact positions, structural connectivity, and medication state. Beta-HFO PAC (mainly in the 200-500 Hz range) was observed in all subjects. PAC was detectable more specifically in the motor part of the STN compared to beta power and HFOs. Moreover, the presence of PAC better corresponds to the stimulation setup based on the clinical effect. PAC is also sensitive to the laterality of symptoms and dopaminergic therapy, where the greater PAC cluster reflects the more affected side and medication "off" state. Coupling between beta power and HFOs is known to be a correlate of the PD "off" state. Beta-HFO PAC seems to be more sensitive than beta power itself and could be more helpful in the selection of the best clinical stimulation contact and probably also as a potential future input signal for aDBS.

End of Life in Boys and Young Men With Duchenne Muscular Dystrophy - The Perspective of Dying Men and Their Families: A Systematic Review and Thematic Synthesis of Qualitative Evidence.

Understanding the perceptions and experiences related to the end of life (EoL) of boys and men with Duchenne muscular dystrophy from their own and/or family perspective is limited based on the available qualitative empirical studies. This systematic review was done with a thematic synthesis of qualitative evidence according to the PRISMA Statement Guidelines and the SPIDER search tool. The review included empirical, qualitative, and relevant full-text studies published in 2000-2023 in the EBSCO Discovery Service, ISI Web of Science, Scopus, PubMed, and ProQuest databases. From o total of eight included qualitative studies, four main key themes were identified: "Being a parent/caregiver" - psychosocial aspects, needs, and experiences; "Communication about EoL with healthcare and other professionals" - positive experiences and personal shortcomings; "Discussions about…" - the issue of EoL, dying and death; and "End of life" - end-of-life care, planning and the need for palliative care.

Intraoperative electrophysiological monitoring determines the final electrode position for pallidal stimulation in dystonia patients.

Background: Bilateral deep brain stimulation (DBS) of the globus pallidus internus (GPi) is an effective treatment for refractory dystonia. Neuroradiological target and stimulation electrode trajectory planning with intraoperative microelectrode recordings (MER) and stimulation are used. With improving neuroradiological techniques, the need for MER is in dispute mainly because of the suspected risk of hemorrhage and the impact on clinical post DBS outcome. Objective: The aim of the study is to compare the preplanned GPi electrode trajectories with final trajectories selected for electrode implantation after electrophysiological monitoring and to discuss the factors potentially responsible for differences between preplanned and final trajectories. Finally, the potential association between the final trajectory selected for electrode implantation and clinical outcome will be analyzed. Methods: Forty patients underwent bilateral GPi DBS (right-sided implants first) for refractory dystonia. The relationship between preplanned and final trajectories (MicroDrive system) was correlated with patient (gender, age, dystonia type and duration) and surgery characteristics (anesthesia type, postoperative pneumocephalus) and clinical outcome measured using CGI (Clinical Global Impression parameter). The correlation between the preplanned and final trajectories together with CGI was compared between patients 1-20 and 21-40 for the learning curve effect. Results: The trajectory selected for definitive electrode implantation matched the preplanned trajectory in 72.5% and 70% on the right and left side respectively; 55% had bilateral definitive electrodes implanted along the preplanned trajectories. Statistical analysis did not confirm any of the studied factors as predictor of the difference between the preplanned and final trajectories. Also no association between CGI and final trajectory selected for electrode implantation in the right/left hemisphere has been proven. The percentages of final electrodes implanted along the preplanned trajectory (the correlation between anatomical planning and intraoperative electrophysiology results) did not differ between patients 1-20 and 21-40. Similarly, there were no statistically significant differences in CGI (clinical outcome) between patients 1-20 and 21-40. Conclusion: The final trajectory selected after electrophysiological study differed from the preplanned trajectory in a significant percentage of patients. No predictor of this difference was identified. The anatomo-electrophysiological difference was not predictive of the clinical outcome (as measured using CGI parameter).

Twenty-five years of epilepsy surgery at a Central European comprehensive epilepsy center-Trends in intervention delay and outcomes.

OBJECTIVE: We analyzed trends in patients' characteristics, outcomes, and waiting times over the last 25 years at our epilepsy surgery center situated in Central Europe to highlight possible areas of improvement in our care for patients with drug-resistant epilepsy. METHODS: A total of 704 patients who underwent surgery at the Brno Epilepsy Center were included in the study, 71 of those were children. Patients were separated into three time periods, 1996-2000 (n = 95), 2001-2010 (n = 295) and 2011-2022 (n = 314) based on first evaluation at the center. RESULTS: The average duration of epilepsy before surgery in adults remained high over the last 25 years (20.1 years from 1996 to 2000, 21.3 from 2001 to 2010, and 21.3 from 2011 to 2020, P = 0.718). There has been a decrease in rate of surgeries for temporal lobe epilepsy in the most recent time period (67%-70%-52%, P < 0.001). Correspondingly, extratemporal resections have become more frequent with a significant increase in surgeries for focal cortical dysplasia (2%-8%-19%, P < 0.001). For resections, better outcomes (ILAE scores 1a-2) have been achieved in extratemporal lesional (0%-21%-61%, P = 0.01, at least 2-year follow-up) patients. In temporal lesional patients, outcomes remained unchanged (at least 77% success rate). A longer duration of epilepsy predicted a less favorable outcome for resective procedures (P = 0.024) in patients with disease duration of less than 25 years. SIGNIFICANCE: The spectrum of epilepsy surgery is shifting toward nonlesional and extratemporal cases. While success rates of extratemporal resections at our center are getting better, the average duration of epilepsy before surgical intervention is still very long and is not improving. This underscores the need for stronger collaboration between epileptologists and outpatient neurologists to ensure prompt and effective treatment for patients with drug-resistant epilepsy.

The effect of deep brain stimulation in Parkinson's disease reflected in EEG microstates.

Mechanisms of deep brain stimulation (DBS) on cortical networks were explored mainly by fMRI. Advanced analysis of high-density EEG is a source of additional information and may provide clinically useful biomarkers. The presented study evaluates EEG microstates in Parkinson's disease and the effect of DBS of the subthalamic nucleus (STN). The association between revealed spatiotemporal dynamics of brain networks and changes in oscillatory activity and clinical examination were assessed. Thirty-seven patients with Parkinson's disease treated by STN-DBS underwent two sessions (OFF and ON stimulation conditions) of resting-state EEG. EEG microstates were analyzed in patient recordings and in a matched healthy control dataset. Microstate parameters were then compared across groups and were correlated with clinical and neuropsychological scores. Of the five revealed microstates, two differed between Parkinson's disease patients and healthy controls. Another microstate differed between ON and OFF stimulation conditions in the patient group and restored parameters in the ON stimulation state toward to healthy values. The mean beta power of that microstate was the highest in patients during the OFF stimulation condition and the lowest in healthy controls; sources were localized mainly in the supplementary motor area. Changes in microstate parameters correlated with UPDRS and neuropsychological scores. Disease specific alterations in the spatiotemporal dynamics of large-scale brain networks can be described by EEG microstates. The approach can reveal changes reflecting the effect of DBS on PD motor symptoms as well as changes probably related to non-motor symptoms not influenced by DBS.

Spinal Metastasis in a Patient with Supratentorial Glioblastoma with Primitive Neuronal Component: A Case Report with Clinical and Molecular Evaluation.

Glioblastoma (GBM) is regarded as an aggressive brain tumor that rarely develops extracranial metastases. Despite well-investigated molecular alterations in GBM, there is a limited understanding of these associated with the metastatic potential. We herein present a case report of a 43-year-old woman with frontal GBM with primitive neuronal component who underwent gross total resection followed by chemoradiation. Five months after surgery, the patient was diagnosed with an intraspinal GBM metastasis. Next-generation sequencing analysis of both the primary and metastatic GBM tissues was performed using the Illumina TruSight Tumor 170 assay. The number of single nucleotide variants observed in the metastatic sample was more than two times higher. Mutations in TP53, PTEN, and RB1 found in the primary and metastatic tissue samples indicated the mesenchymal molecular GBM subtype. Among others, there were two inactivating mutations (Arg1026Ile, Trp1831Ter) detected in the NF1 gene, two novel NOTCH3 variants of unknown significance predicted to be damaging (Pro1505Thr, Cys1099Tyr), one novel ARID1A variant of unknown significance (Arg1046Ser), and one gene fusion of unknown significance, EIF2B5-KIF5B, in the metastatic sample. Based on the literature evidence, the alterations of NF1, NOTCH3, and ARID1A could explain, at least in part, the acquired invasiveness and metastatic potential in this particular GBM case.

Deep Brain Stimulation during Pregnancy and Delivery: Review of Current Literature.

Deep brain stimulation (DBS) is an established method in the treatment of not only Parkinson's disease motor complications but also dystonia and tremor, and there are data supporting the efficacy of DBS in epilepsy and some psychiatric problems. The alleviation of the neurologic problems may enable females of childbearing age to consider pregnancy because of being able to take care of their child. The aim of the study is to provide a review of the data available on the effect of DBS on the course of pregnancy and delivery in patients suffering from diseases amenable for DBS treatment (Parkinson's disease, dystonia, obsessive compulsive disorder, Tourette's syndrome, epilepsy). Although data available in the literature on pregnancy and childbirth in patients with an implanted active DBS system are limited to small case series and case reports, the number of younger patients implanted with DBS systems will potentially require more attention beyond specialized DBS centers. In emergency deliveries, general obstetricians and neurosurgeons should be provided with a protocol to prevent injuries to the implanted system with potentially devastating consequences for the patient.

Vagus nerve stimulation outcome prediction: from simple parameters to advanced models.

Since its approval as an adjunct treatment for refractory partial epilepsy, the positive effects of vagus nerve stimulation (VNS) on seizure frequency and severity have been supported by many studies. Seizure reduction of more than 50 % can be expected in at least 50 % of patients. However, a complete post-VNS seizure freedom is rarely achieved and 25 % of patients do not benefit from VNS. Our study provides an overview of the potential predictors of VNS response, from the most simple and basic data to sophisticated EEG processing studies and functional imaging studying brain connectivity. The data support better outcomes in younger patients with early VNS implantation, in patients with posttraumatic epilepsy or tuberous sclerosis, and in patients without bilateral interictal epileptiform discharges. The variability of heart activity has also been studied with some promising results. Because the generally accepted hypothesis of the VNS mechanism is the modulation of synaptic activity in multiple cortical and subcortical regions of the brain, the studies of brain response to external stimulation and/or of brain connectivity were used for models predicting the effect of VNS in individual patients. Although the predictive value of these models is high, the required special equipment and sophisticated mathematical tools limit their routine use (Ref. 58). Keywords: epilepsy, vagus nerve stimulation, response predictor, EEG.

Prediction of Vagal Nerve Stimulation Efficacy in Drug-Resistant Epilepsy (PRECISE): Prospective Study for Pre-implantation Prediction/Study Design.

Background: Vagal nerve stimulation (VNS) can be indicated in patients with drug-resistant epilepsy, who are not eligible for resective epilepsy surgery. In VNS therapy, the responder rate (i.e., percentage of subjects experiencing ≥50% seizure reduction) is ~50%. At the moment, there is no widely-accepted possibility to predict VNS efficacy in a particular patient based on pre-implantation data, which can lead to unnecessary surgery and improper allocation of financial resources. The principal aim of PRediction of vagal nerve stimulation EfficaCy In drug-reSistant Epilepsy (PRECISE) study is to verify the predictability of VNS efficacy by analysis of pre-implantation routine electroencephalogram (EEG). Methods: PRECISE is designed as a prospective multicentric study in which patients indicated to VNS therapy will be recruited. Patients will be classified as predicted responders vs. predicted non-responders using pre-implantation EEG analyses. After the first and second year of the study, the real-life outcome (responder vs. non-responder) will be determined. The real-life outcome and predicted outcome will be compared in terms of accuracy, specificity, and sensitivity. In the meantime, the patients will be managed according to the best clinical practice to obtain the best therapeutic response. The primary endpoint will be the accuracy of the statistical model for prediction of response to VNS therapy in terms of responders and non-responders. The secondary endpoint will be the quantification of differences in EEG power spectra (Relative Mean Power, %) between real-life responders and real-life non-responders to VNS therapy in drug-resistant epilepsy and the sensitivity and specificity of the model. Discussion: PRECISE relies on the results of our previous work, through which we developed a statistical classifier for VNS response (responders vs. non-responders) based on differences in EEG power spectra dynamics (Pre-X-Stim). Trial Registration: www.ClinicalTrials.gov, identifier: NCT04935567.

Pregnancy Outcomes in Refractory Epilepsy Patients with Vagus Nerve Stimulation: Long-Term Single-Center Experience.

BACKGROUND AND STUDY AIMS: Vagus nerve stimulation (VNS) has been employed worldwide as an adjunctive therapy in drug-resistant epilepsy patients. However, the mechanisms of VNS action potentially increase the risk of obstetric complications. The study presents the long-term single-center experience with pregnancies and childbirth in women with VNS for refractory epilepsy based on prospectively collected epileptologic data and a retrospective analysis of pregnancy, childbirth, and data about long-term child development. MATERIAL AND METHODS: From a group of patients with VNS implanted for refractory epilepsy between October 1999 and January 2018, all the women of childbearing age (younger than 40 years) were identified. After checking their hospital records for data about any pregnancies, the women with confirmed childbirth during active VNS stimulation and their general practitioners were interviewed based on a prepared questionnaire regarding their gynecologic history, the course of pregnancy and childbirth, gestational week, birth weight and length, any congenital anomalies of the child, and the child's psychomotor development, school performance, and somatic health problems. RESULTS: From the group of 257 patients implanted with VNS for refractory epilepsy, 4 women (1.5%) became pregnant and gave birth (all on polypharmacotherapy). The mean interval from VNS implantation to birth was 44.3 months. Slight seizure worsening during the last trimester was reported in one woman. In one patient, acute caesarean section was required due to placental separation. Planned birth induction and caesarean section were used in the other two women because of their seizure disorder. No malfunction of the stimulation system was detected during pregnancy or after birth. No congenital malformations were observed. The two children who were of school age at the time of this study require special schooling. CONCLUSIONS: The study results confirmed a high rate of obstetric interventions in patients with VNS. Although no teratogenic effect of VNS has been proven, the higher incidence of children exposed to VNS needing special education requires attention.

A Novel Statistical Model for Predicting the Efficacy of Vagal Nerve Stimulation in Patients With Epilepsy (Pre-X-Stim) Is Applicable to Different EEG Systems.

Background: Identifying patients with intractable epilepsy who would benefit from therapeutic chronic vagal nerve stimulation (VNS) preoperatively remains a major clinical challenge. We have developed a statistical model for predicting VNS efficacy using only routine preimplantation electroencephalogram (EEG) recorded with the TruScan EEG device (Brazdil et al., 2019). It remains to be seen, however, if this model can be applied in different clinical settings. Objective: To validate our model using EEG data acquired with a different recording system. Methods: We identified a validation cohort of eight patients implanted with VNS, whose preimplantation EEG was recorded on the BrainScope device and who underwent the EEG recording according to the protocol. The classifier developed in our earlier work, named Pre-X-Stim, was then employed to classify these patients as predicted responders or non-responders based on the dynamics in EEG power spectra. Predicted and real-world outcomes were compared to establish the applicability of this classifier. In total, two validation experiments were performed using two different validation approaches (single classifier or classifier voting). Results: The classifier achieved 75% accuracy, 67% sensitivity, and 100% specificity. Only two patients, both real-life responders, were classified incorrectly in both validation experiments. Conclusion: We have validated the Pre-X-Stim model on EEGs from a different recording system, which indicates its application under different technical conditions. Our approach, based on preoperative EEG, is easily applied and financially undemanding and presents great potential for real-world clinical use.

Memory outcomes of temporal lobe surgery in adults aged over 45 years.

OBJECTIVE: It is assumed that temporal lobe resection in older people is associated with worse seizure outcomes and potential postsurgical memory decline. We studied postsurgical memory development and surgical efficacy in patients over 45 years of age compared with younger patients. METHODS: We studied 88 patients (51 male and 37 female) after temporal lobe surgery, which involved hippocampal resection. The patients were evaluated before surgery and in the first (72 patients) and/or third (57 patients) postsurgical year. The Wechsler Memory Scale III test was performed to evaluate the MQ postsurgical development. Engel's classification was used to evaluate the postsurgical seizure outcome. RESULTS: The presurgical MQ (median 88) in ≥45 years age group was significantly lower than in both younger groups (median MQ = 100 for ≤30 years age group, p = 0.002; median MQ = 107 for 31-44 years age group, p = 0.002). Three years after the surgery, the MQ decreased significantly in ≤30 years age group (p = 0.012), while only non-significant MQ decline was observed in both older groups. We found no significant impact of age on the surgical outcome. CONCLUSION: Higher age at the time of surgery does not significantly increase the risk for postsurgical memory decline; however, older patients are more likely to have lowered presurgical MQ. We did not find significant differences in the impact of surgery on seizure outcome among the age groups. Epilepsy surgery appears to be a safe and effective method in the age over 45 years even though an earlier surgery should be preferred.

Mozart effect in epilepsy: Why is Mozart better than Haydn? Acoustic qualities-based analysis of stereoelectroencephalography.

BACKGROUND AND PURPOSE: We aimed to confirm the Mozart effect in epileptic patients using intracerebral electroencephalography recordings and the hypothesis that the reduction of epileptiform discharges (EDs) can be explained by the music's acoustic properties. METHODS: Eighteen epilepsy surgery candidates were implanted with depth electrodes in the temporal medial and lateral cortex. Patients listened to the first movement of Mozart's Sonata for Two Pianos K. 448 and to the first movement of Haydn's Symphony No. 94. Musical features from each composition with respect to rhythm, melody, and harmony were analyzed. RESULTS: Epileptiform discharges in intracerebral electroencephalography were reduced by Mozart's music. Listening to Haydn's music led to reduced EDs only in women; in men, the EDs increased. The acoustic analysis revealed that nondissonant music with a harmonic spectrum and decreasing tempo with significant high-frequency parts has a reducing effect on EDs in men. To reduce EDs in women, the music should additionally be gradually less dynamic in terms of loudness. Finally, we were able to demonstrate that these acoustic characteristics are more dominant in Mozart's music than in Haydn's music. CONCLUSIONS: We confirmed the reduction of intracerebral EDs while listening to classical music. An analysis of the musical features revealed that the acoustic characteristics of music are responsible for suppressing brain epileptic activity. Based on our study, we suggest studying the use of musical pieces with well-defined acoustic properties as an alternative noninvasive method to reduce epileptic activity in patients with epilepsy.

Successful asymmetrical deep brain stimulation using right subthalamic and left pallidal electrodes in a patient with Parkinson's disease.

PURPOSE: Despite the best efforts of neurologists, the results of pharmacotherapy in the late stages of Parkinson's disease are often disappointing and accompanied by debilitating side effects. Under these circumstances, deep brain stimulation is a viable treatment option. The aim of the meticulous pre-surgical planning is not only precise electrode implantation, but also the avoidance of intraoperative vascular conflicts potentially causing intracerebral bleeding. MATERIAL AND METHODS: In this report, we present a patient with early-onset Parkinson's disease whose cerebral vascular anatomy precluded standard bilateral subthalamic nucleus electrode implantation. Initially, right subthalamic stimulation alone provided a very mild clinical benefit that was not reflected in the patient's quality of life. In this patient, an unusual configuration of intracerebral electrodes with right subthalamic and left pallidal stimulation electrodes was applied 15 months after the initial subthalamic electrode implantation. RESULTS: The procedure has had a highly beneficial long-term effect without any significant complications. The greatest improvement was noted using the setting 1.8 V, 130 Hz, 90 µs at the right side (STN) and 3.7 V, 130 Hz, 120 µs at the left side (GPi). This allowed the patient to return to his daily life activities. CONCLUSIONS: The reported case provides a new perspective of treatment possibilities in complex functional neurosurgical cases requiring exceptional individualisation of the treatment approach.

High frequency oscillations in epileptic and non-epileptic human hippocampus during a cognitive task.

Hippocampal high-frequency electrographic activity (HFOs) represents one of the major discoveries not only in epilepsy research but also in cognitive science over the past few decades. A fundamental challenge, however, has been the fact that physiological HFOs associated with normal brain function overlap in frequency with pathological HFOs. We investigated the impact of a cognitive task on HFOs with the aim of improving differentiation between epileptic and non-epileptic hippocampi in humans. Hippocampal activity was recorded with depth electrodes in 15 patients with focal epilepsy during a resting period and subsequently during a cognitive task. HFOs in ripple and fast ripple frequency ranges were evaluated in both conditions, and their rate, spectral entropy, relative amplitude and duration were compared in epileptic and non-epileptic hippocampi. The similarity of HFOs properties recorded at rest in epileptic and non-epileptic hippocampi suggests that they cannot be used alone to distinguish between hippocampi. However, both ripples and fast ripples were observed with higher rates, higher relative amplitudes and longer durations at rest as well as during a cognitive task in epileptic compared with non-epileptic hippocampi. Moreover, during a cognitive task, significant reductions of HFOs rates were found in epileptic hippocampi. These reductions were not observed in non-epileptic hippocampi. Our results indicate that although both hippocampi generate HFOs with similar features that probably reflect non-pathological phenomena, it is possible to differentiate between epileptic and non-epileptic hippocampi using a simple odd-ball task.

Title analysis of (systematic) scoping review studies: Chaos or consistency?

The scoping review is one of the alternatives of producing a literature review. However, this approach still lacks a clearly accepted definition, and the scoping terminology is also somewhat fuzzy. Although the methodology of scoping review processing is relatively uniform, terminological chaos appears in the titles of studies with scoping review methodology. This paper presents an analysis of selected published studies with a focus on the content of their titles. A total of 13 thematic dimensions were identified covering the content of titles that show a degree of inconsistency and frequent terminological and methodological "chaos." This study includes a broad scope of themes and areas for which scoping reviews were produced. We would like to recommend to authors (especially scoping review beginners) to - if not necessary or desirable - avoid introducing new concepts and specifications of titles of produced and published scoping review studies. In the case of literature reviews and knowledge synthesis it is necessary to search according to specific keywords and search phrases - more fragmented scoping review terminology makes literature search more difficult or even impossible.

Reoperations after surgery for acute subdural hematoma: reasons, risk factors, and effects.

PURPOSE: To analyze the reasons and patient-related and injury-related risk factors for reoperation after surgery for acute subdural hematoma (SDH) and the effects of reoperation on treatment outcome. METHODS: Among adult patients operated on for acute SDH between 2013 and 2017, patients reoperated within 14 days after the primary surgery were identified. In all patients, parameters were identified that related to the patient (age, anticoagulation, antiplatelet, and antiepileptic treatment, and alcohol intoxication), trauma (Glasgow Coma Score, SDH thickness, midline shift, midline shift /hematoma thickness rate, other surgical lesion, primary surgery-trephination, craniotomy, or decompressive craniotomy), and Glasgow Outcome Score (GOS). The reasons for reoperation and intervals between primary surgery and reoperation were studied. RESULTS: Of 86 investigated patients, 24 patients were reoperated (27.9%), with a median interval of 2 days between primary surgery and reoperation. No significant differences in patients and injury-related factors were found between reoperated and non-reoperated patients. The rate of primary craniectomies was higher in non-reoperated patients (P = 0.066). The main indications for reoperation were recurrent /significant residual SDH (10 patients), contralateral SDH (5 patients), and expansive intracerebral hematoma or contusion (5 patients). The final median GOS was 3 in non-reoperated and 1.5 in reoperated patients, with good outcomes in 41.2% of non-reoperated and 16.7% of reoperated patients. CONCLUSIONS: Reoperation after acute SDH surgery is associated with a significantly worse prognosis. Recurrent /significant residual SDH and contralateral SDH are the most frequently found reasons for reoperation. None of the analyzed parameters were significant reoperation predictors.

Anterior thalamic deep brain stimulation in epilepsy and persistent psychiatric side effects following discontinuation.

We report a case of a patient with drug-resistant epilepsy treated with deep brain stimulation of the anterior nucleus of the thalamus (ANT-DBS). The patient developed psychiatric side effects (PSEs), namely irritability, hostility, aggressiveness, and paranoia, after implantation and stimulation initiation. The stimulation was discontinued and the PSEs were mitigated, but the patient did not return to her pre-implantation state, as documented by repeated psychiatric reports and hospitalizations. To our knowledge, this is the first report of a patient who developed long-term PSEs that did not disappear after stimulation discontinuation. We suppose that ANT-DBS caused a persistent perturbation of the thalamic neuronal networks that are responsible for long-term PSEs.

EEG Reactivity Predicts Individual Efficacy of Vagal Nerve Stimulation in Intractable Epileptics.

Background: Chronic vagal nerve stimulation (VNS) is a well-established non-pharmacological treatment option for drug-resistant epilepsy. This study sought to develop a statistical model for prediction of VNS efficacy. We hypothesized that reactivity of the electroencephalogram (EEG) to external stimuli measured during routine preoperative evaluation differs between VNS responders and non-responders. Materials and Methods: Power spectral analyses were computed retrospectively on pre-operative EEG recordings from 60 epileptic patients with VNS. Thirty five responders and 25 non-responders were compared on the relative power values in four standard frequency bands and eight conditions of clinical assessment-eyes opening/closing, photic stimulation, and hyperventilation. Using logistic regression, groups of electrodes within anatomical areas identified as maximally discriminative by n leave-one-out iterations were used to classify patients. The reliability of the predictive model was verified with an independent data-set from 22 additional patients. Results: Power spectral analyses revealed significant differences in EEG reactivity between responders and non-responders; specifically, the dynamics of alpha and gamma activity strongly reflected VNS efficacy. Using individual EEG reactivity to develop and validate a predictive model, we discriminated between responders and non-responders with 86% accuracy, 83% sensitivity, and 90% specificity. Conclusion: We present a new statistical model with which EEG reactivity to external stimuli during routine presurgical evaluation can be seen as a promising avenue for the identification of patients with favorable VNS outcome. This novel method for the prediction of VNS efficacy might represent a breakthrough in the management of drug-resistant epilepsy, with wide-reaching medical and economic implications.

Hippocampal high frequency oscillations in unilateral and bilateral mesial temporal lobe epilepsy.

OBJECTIVE: The main aim of this study was to investigate the potential differences in terms of interictal high frequency oscillations (HFOs) between both hippocampi in unilateral (U-MTLE) and bilateral mesial temporal lobe epilepsy (B-MTLE). METHODS: Sixteen patients with MTLE underwent bilateral hippocampal depth electrode implantation as part of epilepsy surgery evaluation. Interictal HFOs were detected automatically. The analyses entail comparisons of the rates and spatial distributions of ripples and fast ripples (FR) in hippocampi and amygdalae, with respect to the eventual finding of hippocampal sclerosis (HS). RESULTS: In U-MTLE, higher ripple and FR rates were found in the hippocampi ipsilateral to the seizure onset than in the contralateral hippocampi. Non-epileptic hippocampi in U-MTLE were distinguished by significantly lower ripple rate than in the remaining analyzed hippocampi. There were not differences between the hippocampi in B-MTLE. In the hippocampi with proven HS, higher FR rates were observed in the ventral than in the dorsal parts. CONCLUSIONS: Non-epileptic hippocampi in U-MTLE demonstrated significantly lower ripple rates than those epileptic in U-MTLE and B-MTLE. SIGNIFICANCE: Low interictal HFO occurrence might be considered as a marker of the non-epileptic hippocampi in MTLE.