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OBJECTIVE: In the presurgical evaluation of patients with drug-resistant epilepsy (DRE), occasionally, patients do not experience spontaneous typical seizures (STS) during a stereo-electroencephalography (SEEG) study, which limits its effectiveness. We sought to identify risk factors for patients who did not have STS during SEEG and to analyze the clinical outcomes for this particular set of patients. METHODS: We conducted a retrospective analysis of all patients with DRE who underwent depth electrode implantation and SEEG recordings between January 2013 and December 2018. RESULTS: SEEG was performed in 155 cases during this period. 11 (7.2%) did not experience any clinical seizures (non-STS group), while 143 experienced at least one patient-typical seizure during admission (STS group). No significant differences were found between STS and non-STS groups in terms of patient demographics, lesional/non-lesional epilepsy ratio, pre-SEEG seizure frequency, number of ASMs used, electrographic seizures or postoperative seizure outcome in those who underwent resective surgery. Statistically significant differences were found in the average number of electrodes implanted (7.0 in the non-STS group vs. 10.2 in STS), days in Epilepsy Monitoring Unit (21.8 vs. 12.8 days) and the number of cases that underwent resective surgery following SEEG (27.3% vs. 60.8%), respectively. The three non-STS patients (30%) who underwent surgery, all had their typical seizures triggered during ECS studies. Three cases were found to have psychogenic non-epileptic seizures. None of the patients in the non-STS group were offered neurostimulation devices. Five of the non-STS patients experienced transient seizure improvement following SEEG. SIGNIFICANCE: We were unable to identify any factors that predicted lack of seizures during SEEG recordings. Resective surgery was only offered in cases where ECS studies replicated patient-typical seizures. Larger datasets are required to be able to identify factors that predict which patients will fail to develop seizures during SEEG.

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While most patients with depression respond to pharmacotherapy and psychotherapy, about one-third will present treatment resistance to these interventions. For patients with treatment-resistant depression (TRD), invasive neurostimulation therapies such as vagus nerve stimulation, deep brain stimulation, and epidural cortical stimulation may be considered. We performed a narrative review of the published literature to identify papers discussing clinical studies with invasive neurostimulation therapies for TRD. After a database search and title and abstract screening, relevant English-language articles were analyzed. Vagus nerve stimulation, approved by the U.S. Food and Drug Administration as a TRD treatment, may take several months to show therapeutic benefits, and the average response rate varies from 15.2-83%. Deep brain stimulation studies have shown encouraging results, including rapid response rates (> 30%), despite conflicting findings from randomized controlled trials. Several brain regions, such as the subcallosal-cingulate gyrus, nucleus accumbens, ventral capsule/ventral striatum, anterior limb of the internal capsule, medial-forebrain bundle, lateral habenula, inferior-thalamic peduncle, and the bed-nucleus of the stria terminalis have been identified as key targets for TRD management. Epidural cortical stimulation, an invasive intervention with few reported cases, showed positive results (40-60% response), although more extensive trials are needed to confirm its potential in patients with TRD.

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INTRODUCTION: Diffuse gliomas are brain neoplasms with an infiltrative growing pattern to cortical and subcortical structures, frequently adjacent to eloquent areas; direct cortical and subcortical stimulation in awake craniotomy is a useful tool to achieve a gross total resection with the least neurological deficit. PRESENTATION OF CASES: A 24 years old male presented with tonic-clonic seizures. The magnetic resonance imaging (MRI) showed a left parietal glioma. Awake craniotomy was performed using neuronavigation system and brain mapping with cortical and subcortical stimulation. Functional areas were found at the rostral margin of the tumor; however, the rest of the tumor was almost totally resected. Patient was discharged without neurological deficit. A 29 years old male presented in two occasions generalized tonic-clonic seizures, with right hemiparesis. The MRI showed a left parietal glioma. Awake craniotomy was performed using neuronavigation system and brain mapping with cortical and subcortical stimulation, achieving a gross total resection. Patient was discharged without neurological deficit. CONCLUSIONS: Awake craniotomy with brain mapping by cortical and subcortical stimulation and neuronavigation, are the best assets to treat diffuse gliomas and achieve a gross total resection, ensuring the major disease-free interval and preserving the function of eloquent areas.

INTRODUCCIÓN: Los gliomas difusos son neoplasias cerebrales con un patrón de crecimiento infiltrativo, frecuentemente adyacentes a áreas elocuentes. El mapeo cerebral con estimulación cortico-subcortical con el paciente despierto es una herramienta útil para lograr la mayor resección con el menor déficit posoperatorio. PRESENTACIÓN DE CASOS: Varón de 24 años con crisis tónico-clónicas. La resonancia magnética (RM) mostró un glioma parietal izquierdo. Se realizó cirugía con el paciente despierto y mapeo cerebral por estimulación cortical y subcortical directa. Se obtuvo una resección casi total, ya que se encontraron áreas fucionales en el borde rostral del tumor. El paciente egresó sin déficit neurológico. Varón de 29 años que presenta crisis tónico-clónicas generalizadas, acompañadas de hemiparesia derecha. La RM reportó un glioma parietal izquierdo. Se realizó cirugía con el paciente despierto y mapeo cerebral por estimulación cortical y subcortical directa. Se logró una resección total y el paciente egresó sin déficit. CONCLUSIONES: La cirugía con el paciente despierto con mapeo por estimulación directa y neuronavegación es la mejor opción en el tratamiento de los gliomas difusos, para lograr una resección máxima tumoral asegurando un mayor tiempo libre de enfermedad y la conservación de la función de áreas elocuentes.

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OBJECTIVES: To determine whether high-frequency 250-500 Hz monopolar stimulation is effective for mapping cortical and subcortical language structures during brain tumor resection. METHODS: Using high-frequency monopolar stimulation, we mapped the speech areas of 41 awake patients undergoing brain tumor resection in the dominant hemisphere, subject to risk of lesions in the cortical and subcortical speech tracts. Patients were tested for object naming, semantic and other language tasks. RESULTS: Mapping was positive in 22 out of 41 patients. Nine patients presented clinical worsening immediately after surgery. Only one patient did not recover after the 30-day follow-up. Nineteen patients showed negative mapping for language tracts, none of whom exhibited worsening of symptoms at the final evaluation. The applied method showed 89% sensitivity and 56% specificity rates. CONCLUSIONS: The applied method was effective in identifying cortical and subcortical speech areas during the surgical resection of brain tumors. SIGNIFICANCE: Determining whether monopolar high-frequency stimulation is effective for language mapping is important, since it may be very effective in infiltrating tumor areas and nearby edema region.

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Introducción: la estimulación cortical directa (DCS) es una metodología corrientemente usada para localizar áreas del lenguaje en intervenciones quirúrgicas que incluyan resecciones.La estimulación magnética transcraneana repetitiva (rTMS) a demostrado también su capacidad para inducir alteraciones transitorias. Recientemente el desarrollo del Sistema de Navegación de TMS asegura precisa localización del sitio estimulado. El objetivo del trabajo es estudiar la confiabilidad de la estimulación magnética transcraneal repetitiva navegada (nrTMS) en la localización de los sitios del lenguaje. Métodos: Once pacientes seleccionados para mapeo del lenguaje por DCS fueron evaluados pre-cirugía con nrTMS. Los mapeos de lenguaje prequirúrgicos mediante nrTMS fueron comparados con DCS. Resultados: Un total de 25 nrTMS sitios del lenguaje y 38 DCS fueron localizados. La sensibilidad y la especificidad obtenida fue de 88.4 y 95.6, respectivamente. La distancia media fue evaluada en 4,5mm. Conclusiones: Los dispositivos de nrTMS permiten la identificación de las áreas corticales del lenguaje. Con un alto grado de concordancia con el mapeo TMS. La nrTMS se muestra como una herramienta de interés en la investigación y aplicación práctica en la función del lenguaje.

Introduction: direct cortical stimulation (DCS) is currently used to localise language areas in surgical resections. Repetitive transcranial magnetic stimulation (rTMS) has also shown its capacity to induce transient language alterations. Newly developed Navigated Brain Systems of TMS ensure precise topographical localisation of the stimulated site. The objective was to study the reliability of navigated repetitive transcranial magnetic stimulation (nrTMS) in language sites localisation.Methods: Eleven patients selected for DCS language mapping were presurgically evaluated with nrTMS. These presurgicalnrTMS language maps were then compared with DCS.Results: A total number of 25 nrTMS and 38 DCS language sites were localised. Sensitivity and specificity were calculated as 88.4 and 95.6 respectively. Mean distance was assessed as 4.5 millimetres. Conclusions: nrTMS devices allow identification of cortical language areas, with a high degree of concordance to TMS mapping. NrTMS shows up as an interesting tool for research and practical application in language function.

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O objetivo deste estudo foi a verificação da possibilidade teórica de que a aprendizagem de uma habilidade motora decorra da observação do aprendiz sobre outros praticantes e seja intensificada em função de um protocolo de sintetização de ondas corticais via estimulação cortical. A amostra foi constituída por 15 crianças, de ambos os gêneros, com faixa etária entre 4-5 anos, que foram submetidas a treinamento motor conforme teoria dos neurônios-espelho. Foi realizado eletroencefalograma, em dois momentos da pesquisa (pré e pós-testes) e observada a performance motora dos grupos. Observou-se que, na Fase de Aquisição e Transferência, os grupos obtiveram melhora na performance motora pela diminuição na média de erros absolutos e equilíbrio nas ondas corticais, embora não tenha sido significativa. O estudo da hipótese investigada na abordagem dos neurônios-espelho associada à estimulação cortical demonstrou melhora no desempenho, na agilidade e na capacidade hábil-motriz.

To verify the theoretical possibility that learning a motor skill may come from the observation of other practitioners and be intensified due to the protocol of synthesis of cortical waves via cortical stimulation was the objective of this study. Fifteen children, both male and female, aged 4-to-5 years old, divided randomly into three groups which were submitted to a motor training according to the mirror-neuron theory. Electroencephalogram was carried out pre and post-training in order to verify the possible alterations in the cortical standard, and the motor performance of the groups was observed. It was observed that in the Acquisition and Transference Phase, the group obtained improvement in the motor performance due to the decrease of absolute mistakes average and balance in the cortical waves. The values obtained were not significant. The hypothesis of mirror-neuron approach associated with cortical stimulation demonstrated increased global performance of the group, improving the development, the agility and the skilled-motor capacity.

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O objetivo deste estudo foi a verificação da possibilidade teórica de que a aprendizagem de uma habilidade motora decorra da observação do aprendiz sobre outros praticantes e seja intensificada em função de um protocolo de sintetização de ondas corticais via estimulação cortical. A amostra foi constituída por 15 crianças, de ambos os gêneros, com faixa etária entre 4-5 anos, que foram submetidas a treinamento motor conforme teoria dos neurônios-espelho. Foi realizado eletroencefalograma, em dois momentos da pesquisa (pré e pós-testes) e observada a performance motora dos grupos. Observou-se que, na Fase de Aquisição e Transferência, os grupos obtiveram melhora na performance motora pela diminuição na média de erros absolutos e equilíbrio nas ondas corticais, embora não tenha sido significativa. O estudo da hipótese investigada na abordagem dos neurônios-espelho associada à estimulação cortical demonstrou melhora no desempenho, na agilidade e na capacidade hábil-motriz.(AU)

To verify the theoretical possibility that learning a motor skill may come from the observation of other practitioners and be intensified due to the protocol of synthesis of cortical waves via cortical stimulation was the objective of this study. Fifteen children, both male and female, aged 4-to-5 years old, divided randomly into three groups which were submitted to a motor training according to the mirror-neuron theory. Electroencephalogram was carried out pre and post-training in order to verify the possible alterations in the cortical standard, and the motor performance of the groups was observed. It was observed that in the Acquisition and Transference Phase, the group obtained improvement in the motor performance due to the decrease of absolute mistakes average and balance in the cortical waves. The values obtained were not significant. The hypothesis of mirror-neuron approach associated with cortical stimulation demonstrated increased global performance of the group, improving the development, the agility and the skilled-motor capacity.(AU)

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