Language lateralization in temporal lobe epilepsy: A behavioral screening tool for surgical planning.

OBJECTIVE: Temporal lobe epilepsy can disturb eloquent areas, affecting language. We applied a visually-mediated task to measure lateralization of language recognition in drug-resistant temporal lobe epilepsy. METHOD: Patients with left (n = 26), right (n = 28) temporal lobe epilepsy and controls (n = 30) were administered the translingual lexical decision task. We performed repeated measures analyses of variance, with the visual half-field as an intrasubject factor and the group as an intersubject factor. RESULTS: A main effect of visual half-field was found, showing the right visual field (left hemisphere) advantage for both accuracy and response time. A main effect of the group was found in accuracy, showing that both epilepsy groups performed less accurately than controls, and left temporal lobe epilepsy performed less accurately than right temporal lobe epilepsy. Also, the group-by-visual half-field interaction was significant. Post hoc t tests indicated the controls and right temporal lobe epilepsy performed better in the right visual field than in the left visual field, whereas no visual half-field effect was found in left temporal lobe epilepsy. For response times, the interaction was also significant. Post hoc t tests showed a significant right visual-field advantage for controls (two-tailed) and for the right temporal lobe epilepsy (one-tailed). Right visual-field advantage was absent in left temporal lobe epilepsy. CONCLUSIONS: The translingual lexical decision task can efficiently distinguish between left and right temporal lobe epilepsy. Compared to right temporal lobe epilepsy and controls, language lateralization is diminished in left temporal lobe epilepsy. The potential use of the translingual lexical decision task as an effective noninvasive presurgical language lateralization screening tool is highlighted. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Stereo-EEG features of temporal and frontal lobe seizures with loss of consciousness.

The loss of consciousness (LOC) during seizures is one of the most striking features that significantly impact the quality of life, even though the neuronal network involved is not fully comprehended. We analyzed the intracerebral patterns in patients with focal drug-resistant epilepsy, both with and without LOC. We assessed the localization, lateralization, stereo electroencephalography (SEEG) patterns, seizure duration, and the quantification of contacts exhibiting electrical discharge. The degree of LOC was quantified using the Consciousness Seizure Scale. Thirteen patients (40 seizures) with focal drug-resistant epilepsy underwent SEEG. In cases of temporal lobe epilepsy (TLE, 6 patients and 15 seizures), LOC occurred more frequently in seizures with mesial rather than lateral temporal lobe onset. On the other hand, in cases of frontal lobe epilepsy (7 patients; 25 seizures), LOC was associated with pre-frontal onset, a higher number of contacts with epileptic discharge compared to the onset count and longer seizure durations. Our study revealed distinct characteristics during LOC depending on the epileptogenic zone. For temporal lobe seizures, LOC was associated with mesial seizure onset, whereas in frontal lobe epilepsy, seizure with LOC has a significant increase in contact showing epileptiform discharge and a pre-frontal onset. This phenomenon may be correlated with the broad neural network required to maintain consciousness, which can be affected in different ways, resulting in LOC.

The first genome-wide association study in the Argentinian and Chilean populations identifies shared genetics with Europeans in Alzheimer's disease.

INTRODUCTION: Genome-wide association studies (GWAS) are fundamental for identifying loci associated with diseases. However, they require replication in other ethnicities. METHODS: We performed GWAS on sporadic Alzheimer's disease (AD) including 539 patients and 854 controls from Argentina and Chile. We combined our results with those from the European Alzheimer and Dementia Biobank (EADB) in a meta-analysis and tested their genetic risk score (GRS) performance in this admixed population. RESULTS: We detected apolipoprotein E ε4 as the single genome-wide significant signal (odds ratio  = 2.93 [2.37-3.63], P = 2.6 × 10-23 ). The meta-analysis with EADB summary statistics revealed four new loci reaching GWAS significance. Functional annotations of these loci implicated endosome/lysosomal function. Finally, the AD-GRS presented a similar performance in these populations, despite the score diminished when the Native American ancestry rose. DISCUSSION: We report the first GWAS on AD in a population from South America. It shows shared genetics modulating AD risk between the European and these admixed populations. HIGHLIGHTS: This is the first genome-wide association study on Alzheimer's disease (AD) in a population sample from Argentina and Chile. Trans-ethnic meta-analysis reveals four new loci involving lysosomal function in AD. This is the first independent replication for TREM2L, IGH-gene-cluster, and ADAM17 loci. A genetic risk score (GRS) developed in Europeans performed well in this population. The higher the Native American ancestry the lower the GRS values.

Dancing epilepsy: A stereo encephalography case report.

Ictal semiology is essential to identify the epileptogenic zone (EZ), especially in drug-resistant focal epilepsy (DRE), as its accurate identification determines the surgical prognosis. Dancing is highly unusual ictal semiology, and its underlying neural networks remain somehow unclear since both temporal and frontal lobe (FL) have been implicated in its generation. We present a 21-year-old male with DRE characterized by dancing seizures. Homemade videos were obtained. Through a non-invasive pre-surgical evaluation, the epileptogenic zone was localized within a gross lesion in the left FL. Using stereo electroencephalography (SEEG), we successfully identified the ictal-onset zone in the mesial middle, inferior, and orbito-frontal cortex, with rapid propagation of ictal activity extending backward and laterally to the precentral regions. Subsequently, a left frontal middle and inferior gyrectomy was performed, resulting in seizure freedom for the patient. Pathology results revealed a mild malformation of cortical development with oligodendroglial hyperplasia (MOGHE). Atypical seizure semiology, such as dancing, provides an interesting starting point for the analysis of the areas involved in the EZ. Further intracranial recordings are required to fully comprehend the underlying networks and interactions of cerebral areas during dancing seizures.

Cannabidiol as an adjuvant treatment in adults with drug-resistant focal epilepsy.

Cannabidiol oil (CBD) has been approved as an anti-seizure medication for the treatment of uncommon types of epilepsy, occurring in children: Dravet syndrome, Lennox-Gastaut syndrome, and Tuberous Sclerosis Complex. There are few publications in relation to use the CBD in adult patients with focal drug-resistant epilepsy. The objective of this study was to evaluate the efficacy, tolerability, safety, and quality of life, of adjuvant treatment with CBD, in adult patients with drug-resistant focal epilepsy for at least 6 months. An open, observational, prospective cohort study was conducted using a before-after design (time series) in adult patients undergoing outpatient follow-up in a public hospital in Buenos Aires, Argentina. From a total of 44 patients, 5% of patients were seizure-free, 32% of patients reduced more than 80% of their seizures and 87% of patients reduced 50% of their monthly seizures. Eleven percent presented a decrease of less than 50% in seizure frequency. The average final dose was 335 mg/d orally administered. Thirty-four percent of patients reported mild adverse events and no patient reported severe adverse effects. At the end of the study, we found in most patients a significant improvement in the quality of life, in all the items evaluated. Adjuvant treatment with CBD in adult patients with drug-resistant focal epilepsy was effective, safe, well tolerated, and associated with a significant improvement in their quality of life.

Cultural adaptation and psychometric properties of the Patient-weighted Quality of Life in Epilepsy 31 Inventory (QOLIE-31P) in Argentina.

OBJECTIVE: This study presents the cultural and linguistic adaptation and psychometric properties of the Argentine version of the Quality of Life in Epilepsy Inventory (QOLIE-31P) scale. METHODS: An instrumental study was carried out. A version of QOLIE-31P translated into Spanish was provided by the original authors. To assess the content validity, evaluation of expert judges was requested, and the degree of agreement was determined. The instrument was administered to 212 people with epilepsy (PWE) of Argentina, together with the BDI-II, B-IPQ and a sociodemographic questionnaire. A descriptive analysis of the sample was carried out. Discriminative capacity of the items was performed. Cronbach's alpha was calculated to assess reliability. To study the dimensional structure of the instrument, a confirmatory factorial analysis (CFA) was performed. Convergent and discriminant validity was tested through mean difference tests, linear correlation, and regression analysis. RESULTS: Aiken's V coefficients ranged between .90 and 1 (acceptable), which allows to state that a conceptually and linguistically equivalent version of the QOLIE-31P was reached. Cronbach's Alpha of 0.94 was obtained for the Total Scale (optimal). As a result of CFA, 7 factors were obtained, being the dimensional structure similar to the original version. Also, unemployed PWE reported significant lower scores than employed PWE. Finally, QOLIE-31P scores negatively correlated with depression symptom severity and negative illness perception. CONCLUSION: The Argentine version of the QOLIE-31P is a valid and reliable instrument, presenting good psychometric properties, such as high internal consistency and a dimensional structure similar to that of the original version.

Perfil de fitocannabinoides en muestras derivadas al Laboratorio de control de calidad de la ENyS / Phytocannabinoid profile in samples sent to the ENyS quality control laboratory

[RESUMEN]. Las plantas de cannabis se clasifican en quimiotipos, según las concentraciones relativas de tetrahidrocannabinol (THC) y cannabidiol (CBD). El quimiotipo I tiene alto contenido de THC (sativa dominante); el quimiotipo II tiene un contenido aproximado 1:1 de THC:CBD (híbrida) y el quimiotipo III con CBD como constituyente predominante (indica dominante). El objetivo fue clasificar las muestras recibidas en el Laboratorio de con trol de calidad de la ENyS según su quimiotipo. El análisis de cannabinoides se realizó mediante cromatografía líquida de ultra alta resolución acoplada a espectrometría de masas y se calculó la razón THC/CBD. Se analizaron 121 muestras de tejido vegetal, que tuvieron un fuerte predominio de quimiotipo I (75%) y 139 muestras de aceite, con 41% de quimiotipo I, 40% de quimiotipo II y 19% de quimiotipo III.

[ABSTRACT]. Cannabis plants are classified into chemotypes, based on the relative concentrations of tetrahydrocannabinol (THC) and cannabidiol (CBD). Chemotype I has high THC content (sativa dominant); chemotype II has an approximate 1:1 content of THC:CBD (hybrid) and chemotype III has CBD as the predominant constituent (indica dominant). Our aim was to classify the samples received at the ENyS Quality Control Laboratory according to their chemotype. Cannabinoid analysis was performed using ultra-high-performance liquid chromatography coupled to mass spectrometry and the THC/CBD ratio was calculated. 121 plant tissue samples were analyzed, which had a strong predominance of chemotype I (75%) as well as 139 oil samples, wich rendered 41% chemotype I, 40% chemotype II and 19% chemotype III.

Breastfeeding while on treatment with antiseizure medications: a systematic review from the ILAE Women Task Force

We carried out a systematic review of published information on transfer of antiseizure medications (ASMs) into breastmilk, ASM serum concentrations in breastfed infants, and the wellbeing of infants breastfed by mothers on ASM treatment. Information was extracted from 85 relevant articles. No data on ASM levels in breastmilk or in breastfed infants was identified for cannabidiol, cenobamate, clobazam, eslicarbazepine-acetate, everolimus, felbamate, fenfluramine, retigabine, rufinamide, stiripentol, tiagabine, and vigabatrin. For ASMs, with available information on levels in breastfed infants, very low concentrations (in the order of 10% or less of maternal serum concentrations) were reported for carbamazepine, gabapentin, levetiracetam, oxcarbazepine, phenytoin, valproate, and clonazepam. Slightly higher levels (up to approximately 30% of maternal serum concentrations) have been observed with lamotrigine and topiramate, and in single case reports for brivaracetam, lacosamide, and perampanel. High infant levels (30% up to 100% of maternal serum concentrations) have been reported with ethosuximide, phenobarbital and zonisamide. Adverse infant effects during breastfeeding by mothers on ASMs appear to be rare regardless of the type of ASM, but systematic study is limited. Prospective long-term follow-up studies of developmental outcomes among children who have been breastfed by mothers taking ASMs are sparse and have mainly involved children whose mothers were taking carbamazepine, lamotrigine, levetiracetam, phenytoin or valproate as monotherapy while breastfeeding. Although these studies have not indicated poorer outcome among breastfed children compared with those who were not breastfed, further data on long-term outcomes are needed to draw firm conclusions. It is concluded that breastfeeding should in general be encouraged in women taking ASMs, given the well-established benefits of breastfeeding with regard to both short- and long-term infant health in the general population. Counselling needs to be individualized including information on the current knowledge regarding the woman's specific ASM treatment.

[Medical cannabis]. / Cannabis medicinal.

Health is a human right. In order to guarantee that right, it is fundamental that all activities concerning health in different contexts (clinical, research, teaching) contribute to the construction of an efficient system that promotes excellence, equity, justice, and solidarity. In this issue, we take on alternatives regarding the use of medical cannabis from this perspective. Health research and its contribution to knowledge - in particular with respect to the development of new pharmaceuticals - represents not only a challenge related to technology and production, but also an opportunity for ensuring the autonomy of the health system.

La salud es un derecho humano. Para garantizar ese derecho, resulta esencial que las actividades destinadas a la salud en diferentes niveles, clínica, investigación o docencia contribuyan a generar un sistema eficiente, de excelencia, equitativo, justo y solidario. Desde esta perspectiva, abordamos las opciones del uso del cannabis medicinal. La investigación en salud y su aporte al conocimiento, en especial, en el desarrollo de nuevos productos farmacéuticos representa, además de un desafío productivo y tecnológico, la posibilidad de generar autonomía sanitaria.

Daily rhythms in right-sided and left-sided temporal lobe epilepsy.

Introduction: Epilepsy is closely related to daily rhythms, such as the sleep-wake cycle. The objective of this study was to evaluate the relationship between drug-resistant temporal lobe epilepsy (TLE) and the parameters related to the sleep-wake cycle, seizure time and epilepsy laterality. Methods: Consecutive patients admitted to the video electroencephalogram unit with a diagnosis of TLE were enrolled. Patients were divided into two groups: those with left TLE (LTLE) and those with right TLE (RTLE). They then remained in the conditions of 12-hour light, 12-hour darkness. Demographic data, treatment, number and time of seizure occurrence, sleep diary, morningness-eveningness questionnaire, Pittsburgh Sleep Quality Index and Epworth Sleepiness Scale were recorded. Results: In total, 74 patients with TLE, 43 with LTLE and 31 with RTLE, were studied. RTLE patients showed a significant preference for morningness. Patients treated with benzodiazepines showed worse sleep quality and greater daytime sleepiness. Patients who did not report any clear predominance and patients who reported seizures during wakefulness had significantly more seizures during wakefulness and patients who reported sleep predominance had more seizures during sleep (p>0.001). The LTLE group had a greater number of seizures from 8 to 16 hours, unlike the RTLE group, which had a uniform distribution (p=0.008). Conclusions: This was a prospective study of patients with drug-resistant TLE performed in a controlled environment to study the impact of daily rhythms, seizure frequency and seizure distribution. Laterality seems to be a key factor in seizure distribution.

Brain mapping of emotional prosody in patients with drug-resistant temporal epilepsy: An indicator of plasticity.

INTRODUCTION: Emotional prosody, a suprasegmental component of language, is predominantly processed by right temporo-frontal areas of the cerebral cortex. In temporal lobe epilepsy (TLE), brain disturbances affecting prosody processing frequently occur. This research assesses compensatory brain mechanisms of prosody processing in refractory TLE using fMRI. METHODS: Patients with focal unilateral epilepsy, right (RTLE) (N = 19), left (LTLE) (N = 19), and healthy controls (CTRL) (N = 20) were evaluated during a prosody decoding fMRI task. The stimuli consisted in spoken numbers with different tones of voice (joy, fear, anger, neutral and silent trials). Participants were instructed to label the emotion with a keypad. "Joy" was removed from the analysis due to a high degree of variability. A lateralization index (LI) was used to see individual differences in the interhemispheric activations of each participant. RESULTS: Behaviorally, The LTLE and RTLE groups did not differ significantly from each other neither from CTRL. In Negative Emotions versus Baseline contrast, the whole sample analysis showed extensive activations in bilateral superior temporal gyrus, bilateral precentral and post-central gyrus, right putamen, and left cerebellar vermis. Compared to the LTLE and CTRL, RTLE activated similar areas, but to a lesser extent. The LI analysis revealed significant differences in hemispheric laterality of the temporal lobe and the parietal lobe between RTLE compared to LTLE and CTRL, being the RTLE group lateralized towards the left, unlike the other two groups. DISCUSSION: The LI indicated that, since the CTRL and the LTLE groups recruited putative prosodic regions, the RTLE lateralized prosody processing towards the left, recruiting contralateral nodes, homotopic to the putative areas of the prosody. Considering that the groups did not differ in prosody task performance, the findings suggest that, in the RTLE group, alternative brain nodes were recruited for the task, demonstrating plasticity.

Comorbid impulsivity after one year of epilepsy surgery.

BACKGROUND: Psychiatric comorbidities in patients with drug-resistant epilepsy (DRE) are frequently observed before and after epilepsy surgery. Impulsivity, defined as behaviors that are poorly conceived, are also frequent among patients with epilepsy. The aim of this study was to determine the presence of comorbid impulsivity in patients with DRE after one year of epilepsy surgery. METHODS: Patients who underwent epilepsy surgery for DRE and completed the postsurgical assessment protocol one year after surgery were included. All patients underwent a presurgical protocol comprising of neurological, psychiatric, neuropsychological, video-EEG and MRI assessments. The psychiatric evaluation was performed before and one year after surgery using SCID-I, SCID-II, GAF scale of DSM IV, and Beck Depression Inventory II. One year after surgery, Barratt Impulsiveness Scale 11, and Engel classification of seizures, were administered. RESULTS: A total of 38 patients were included in this study, 21 women (55.3%) and 17 men (44.7%), mean age 36 years (SD = 9.4). Higher impulsivity was associated with a worse epilepsy seizure outcome (p < 0.05), one year after surgery. According to the multiple linear regression analysis, a worse epilepsy seizure outcome was associated with higher levels of nonplanning impulsivity (p < 0.05) (p < 0.05, ß -0.5, r2 0.25). The GAF score was negatively associated with motor score (p < 0.05, ß -0.584, r2 0.42) and with the total BIS-11 score (p < 0.05, ß -0.557, r2 0.39). CONCLUSIONS: Impulsivity has been associated with a worse post-surgical seizure outcome. Larger studies about impulsivity might confirm these preliminary findings.

Psychiatric disorders, depression and quality of life in patients with psychogenic non-epileptic seizures and drug resistant epilepsy living in Argentina.

OBJECTIVES: Psychiatric disorders are frequently found in both patients with PNES and DRE, making the differential diagnosis even more complex. The aim of this study was to analyze and compare psychiatric aspects and the quality of life in patients with psychogenic non-epileptic seizures (PNES) and drug resistant epilepsy (DRE). METHODS: Patients admitted to video-electroencephalograpy (VEEG) unit with confirmed PNES and DRE were included. Demographical characteristics, psychiatric diagnosis according to SCID I and II of DSM IV, pharmacological treatment, general functioning measured with GAF (Global assessment of functionality), quality of life (QoL) using QlesQSF (Quality of Life Enjoyment and Satisfaction Questionnaire Short Form) and depression severity using BDI II (Beck depression inventory), were compared between the groups. Non-parametric tests, chi square test, and logistic regression were used for statistical analysis. RESULTS: 148 patients consecutively admitted to VEEG were included (DRE n = 97; PNES n = 51). Somatization disorder (RR: 13.02, 95% CI: 1.23-137.39, p = 0.03) and a history of trauma (RR: 8.66, 95% CI: 3.21-23.31, p = 0.001) were associated with PNES. The QlesQ score and the GAF score were lower with a higher prevalence of suicide attempts in the PNES group (p < 0.01). A negative correlation was observed between the severity of depression and the quality of life (DRE r = - 0.28, p = 0.013; PNES r = - 0.59, p = 0.001). CONCLUSIONS: Higher psychiatric comorbidity with poorer QoL were found in PNES patients compared to DRE. However, depression comorbidity negatively affected the QoL in both groups. Future studies based on illness perception will be orientated to complete this analysis.

Patients' Explanatory Models about drug-resistant epilepsy in Argentina. A thematic analysis.

OBJECTIVE: The aim of this study is to explore explanatory models (EM) about epilepsy in patients with drug-resistant epilepsy (DRE) in Buenos Aires, Argentina. DESIGN: A qualitative approach gathered data through semi-structured interviews, oriented to gain an in-depth and contextual understanding of EM about epilepsy of patients with DRE. Data collection and analysis were followed by an inductive and interpretive approach informed by the principles of thematic analysis. RESULTS: 75 patients from two public hospitals participated. Emerging codes were grouped into three categories: Biomedical EM, Psychosocial EM, and Traditional EM. Also, factors that trigger or increase the frequency of seizures were reported. CONCLUSIONS: Patients' EM regarding epilepsy are complex, as biological, psychological, and supernatural aspects intertwine. EM represent a method of understanding the way people explain, recognize, and act in relation to a medical condition. Since patients' beliefs regarding their illness are related to mental disorders, and quality of life, EM could shed light on the real impact of illness in the life of people, and, in turn, guide those intervention strategies to the patients' subjectivity, in order to improve the treatment compliance, reduce distress, and improve health-related quality of life, among other aspects.

Hospitalized population diagnosed with Covid-19 in public health centers in the southeastern region of Greater Buenos Aires / [Población hospitalizada con diagnóstico de Covid-19 en los centros de salud públicos de la región sudeste del Gran Buenos Aires]

Introduction: The present work describes the clinical characteristics and interventions to minimize morbidity and mortality in hospitalized patients diagnosed with COVID-19. Methods: It is a prospective cohort investigation of patients who received a response from the Health Centers in the southeast region (RS) of the metropolitan area (AMBA) from April 8 to September 30, 2020. A Situation Room was used epidemiological with two monitoring and follow-up boards, one for bed management and the other for patient management. Results: During the analyzed period, 2,588 patients with confirmed COVID-19 diagnosis were admitted, 1,943 with suspected COVID-19 pathology, and 1,464 subjects with other pathologies. 55% of the patients were men and the mean age was 51 years. There were 82.8% patients with pre-existing diseases, hypertension and diabetes were the most frequent. 14% were hospitalized in the Intensive Care Unit. The mortality of the cohort was 15.05%, mortality was higher for men, with a mean age of 60 years, 92.65% had some pre-existing disease. Conclusion: Our cohort is younger than other published works. Older people, men, and people with comorbidities are at increased risk for COVID-19-related mortality. The public health system was able to respond to the demand without collapsing the hospital institutions.

Introducción: En el presente trabajo se describen las características clínicas y las intervenciones para minimizar la morbimortalidad en pacientes hospitalizados con diagnóstico de COVID-19. Métodos: Es una investigación de cohorte prospectiva de pacientes que recibieron respuesta de los Centros de Salud en la región sudeste (RS) del área metropolitana (AMBA) desde el 8 de abril hasta el 30 de septiembre de 2020. Se utilizó una Sala de Situación epidemiológica con dos tableros de monitoreo y seguimiento, uno de gestión de camas y otro de gestión de pacientes. Resultados: Durante el periodo analizado se internaron2.588pacientes con diagnóstico COVID-19 confirmados, 1.943 con sospecha de patología COVID-19, y 1.464sujetos con otras patologías. El 55% de los pacientes eran hombres y la edad media fue de 51 años. Hubo 82,8% pacientes con enfermedades preexistentes, hipertensión y diabetes fueron las más frecuentes. El 14% fue hospitalizado en la Unidad de Terapia Intensiva. La mortalidad de la cohorte fue del 15,05%, la mortalidad fue mayor para los hombres, con una edad media de 60 años, el 92,65% tenía alguna enfermedad preexistente. Conclusión: Nuestra cohorte es más joven que otros trabajos publicados. Las personas mayores, los hombres y las personas con comorbilidades tienen mayor riesgo de mortalidad relacionada con COVID-19. El sistema de salud público pudo responder a la demanda sin llegar a colapsar las instituciones hospitalarias.

Diagnostic Performance of MRI Volumetry in Epilepsy Patients With Hippocampal Sclerosis Supported Through a Random Forest Automatic Classification Algorithm.

Introduction: Several methods offer free volumetry services for MR data that adequately quantify volume differences in the hippocampus and its subregions. These methods are frequently used to assist in clinical diagnosis of suspected hippocampal sclerosis in temporal lobe epilepsy. A strong association between severity of histopathological anomalies and hippocampal volumes was reported using MR volumetry with a higher diagnostic yield than visual examination alone. Interpretation of volumetry results is challenging due to inherent methodological differences and to the reported variability of hippocampal volume. Furthermore, normal morphometric differences are recognized in diverse populations that may need consideration. To address this concern, we highlighted procedural discrepancies including atlas definition and computation of total intracranial volume that may impact volumetry results. We aimed to quantify diagnostic performance and to propose reference values for hippocampal volume from two well-established techniques: FreeSurfer v.06 and volBrain-HIPS. Methods: Volumetry measures were calculated using clinical T1 MRI from a local population of 61 healthy controls and 57 epilepsy patients with confirmed unilateral hippocampal sclerosis. We further validated the results by a state-of-the-art machine learning classification algorithm (Random Forest) computing accuracy and feature relevance to distinguish between patients and controls. This validation process was performed using the FreeSurfer dataset alone, considering morphometric values not only from the hippocampus but also from additional non-hippocampal brain regions that could be potentially relevant for group classification. Mean reference values and 95% confidence intervals were calculated for left and right hippocampi along with hippocampal asymmetry degree to test diagnostic accuracy. Results: Both methods showed excellent classification performance (AUC:> 0.914) with noticeable differences in absolute (cm3) and normalized volumes. Hippocampal asymmetry was the most accurate discriminator from all estimates (AUC:1~0.97). Similar results were achieved in the validation test with an automatic classifier (AUC:>0.960), disclosing hippocampal structures as the most relevant features for group differentiation among other brain regions. Conclusion: We calculated reference volumetry values from two commonly used methods to accurately identify patients with temporal epilepsy and hippocampal sclerosis. Validation with an automatic classifier confirmed the principal role of the hippocampus and its subregions for diagnosis.

Dementia in Latin America: Paving the way toward a regional action plan.

Across Latin American and Caribbean countries (LACs), the fight against dementia faces pressing challenges, such as heterogeneity, diversity, political instability, and socioeconomic disparities. These can be addressed more effectively in a collaborative setting that fosters open exchange of knowledge. In this work, the Latin American and Caribbean Consortium on Dementia (LAC-CD) proposes an agenda for integration to deliver a Knowledge to Action Framework (KtAF). First, we summarize evidence-based strategies (epidemiology, genetics, biomarkers, clinical trials, nonpharmacological interventions, networking, and translational research) and align them to current global strategies to translate regional knowledge into transformative actions. Then we characterize key sources of complexity (genetic isolates, admixture in populations, environmental factors, and barriers to effective interventions), map them to the above challenges, and provide the basic mosaics of knowledge toward a KtAF. Finally, we describe strategies supporting the knowledge creation stage that underpins the translational impact of KtAF.

Improvements on spatial coverage and focality of deep brain stimulation in pre-surgical epilepsy mapping.

Objective.Electrical stimulation mapping (ESM) of the brain using stereo-electroencephalography (SEEG) intracranial electrodes, also known as depth-ESM (DESM), is being used as part of the pre-surgical planning for brain surgery in drug-resistant epilepsy patients. Typically, DESM consists in applying the electrical stimulation using adjacent contacts of the SEEG electrodes and in recording the EEG responses to those stimuli, giving valuable information of critical brain regions to better delimit the region to resect. However, the spatial extension or coverage of the stimulated area is not well defined even though the precise electrode locations can be determined from computed tomography images.Approach.We first conduct electrical simulations of DESM for different shapes of commercial SEEG electrodes showing the stimulation extensions for different intensities of injected current. We then evaluate the performance of DESM in terms of spatial coverage and focality on two realistic head models of real patients undergoing pre-surgical evaluation. We propose a novel strategy for DESM that consist in applying the current using contacts of different SEEG electrodes (x-DESM), increasing the versatility of DESM without implanting more electrodes. We also present a clinical case where x-DESM replicated the full semiology of an epilepsy seizure using a very low-intensity current injection, when typical adjacent DESM only reproduced partial symptoms with much larger intensities. Finally, we show one example of DESM optimal stimulation to achieve maximum intensity, maximum focality or intermediate solution at a pre-defined target, and one example of temporal interference in DESM capable of increasing focality in brain regions not immediately touching the electrode contacts.Main results.It is possible to define novel current injection patterns using contacts of different electrodes (x-DESM) that might improve coverage and/or focality, depending on the characteristics of the candidate brain. If individual simulations are not possible, we provide the estimated radius of stimulation as a function of the injected current and SEEG electrode brand as a reference for the community.Significance.Our results show that subject-specific electrical stimulations are a valuable tool to use in the pre-surgical planning to visualize the extension of the stimulated regions. The methods we present here are also applicable to pre-surgical planning of tumor resections and deep brain stimulation treatments.