[Functional connectivity derived from an electroencephalogram during non-REM sleep in autism spectrum disorders]. / Conectividad funcional derivada del electroencefalograma durante el sueño no REM en los trastornos del espectro autista.

AIM: To know the differences in the patterns of functional connectivity, the topological characteristics of the network and the relationship between these latter and the interictal epileptiform anomalies in children with primary and secondary autism spectrum disorder (ASD). PATIENTS AND METHODS: A retrospective study was conducted with 27 children aged between 3 and 13 years diagnosed with ASD. Subjects were submitted to an electroencephalogram in a functional state of spontaneous sleep. Functional connectivity and the properties of the network were analysed using data obtained from the electroencephalogram during the N2 stage of non-REM sleep. The frequency of discharge of the interictal epileptiform activity (FDIEA) was determined and was correlated with the topological properties of the network. RESULTS: Synchronisation was diminished in patients with secondary ASD for the alpha frequency and increased for the theta and delta frequency compared with patients with primary ASD. Local alpha efficiency was higher in patients who presented interictal epileptiform activity. Additionally, in patients with secondary ASD there was a statistically significant positive and negative correlation between FDIEA and the topological properties of the network. CONCLUSIONS: Patients with secondary ASD display patterns of functional connectivity that are weaker for the alpha frequency and stronger for theta and delta than patients with primary ASD. In patients with secondary ASD, the interictal epileptiform activity is related to local and global connectivity of the network for the alpha and beta bands during non-REM sleep.

TITLE: Conectividad funcional derivada del electroencefalograma durante el sueño no REM en los trastornos del espectro autista.Objetivo. Conocer las diferencias en los patrones de conectividad funcional, las caracteristicas topologicas de la red y la relacion de estas con las anomalias epileptiformes interictales en niños con trastorno del espectro autista (TEA) primario y secundario. Pacientes y metodos. Se realizo un estudio retrospectivo con 27 niños de 3-13 años diagnosticados con TEA, a los que se les realizo un electroencefalograma en estado funcional de sueño espontaneo. Se analizo la conectividad funcional y las propiedades de la red a partir de los datos obtenidos del electroencefalograma durante la etapa N2 del sueño no REM. Se determino la frecuencia de descarga de la actividad epileptiforme interictal (FDAEI) y se correlaciono con las propiedades topologicas de la red. Resultados. Los pacientes con TEA secundario tenian una disminucion de la sincronizacion para la frecuencia alfa y un incremento para la frecuencia theta y delta en comparacion con los pacientes con TEA primario. La eficiencia local alfa fue mayor en los pacientes que presentaban actividad epileptiforme interictal. Ademas, en los pacientes con TEA secundario, existia una correlacion positiva y negativa estadisticamente significativa entre la FDAEI y las propiedades topologicas de red. Conclusiones. Los pacientes con TEA secundario muestran patrones de conectividad funcional mas debiles para la frecuencia alfa y mas fuerte para la theta y delta que los pacientes con TEA primario. En pacientes con TEA secundario, la actividad epileptiforme interictal se relaciona con la conectividad local y global de la red para las bandas de frecuencia alfa y beta durante el sueño no REM.

Corpora amylacea in the neocortex in patients with temporal lobe epilepsy and focal cortical dysplasia.

INTRODUCTION: Corpora amylacea (CoA) are present in about 60% of atrophic hippocampi resected from patients with drug resistant temporal lobe epilepsy (DRTLE). They have also been described in the lateral temporal neocortex, although less frequently. OBJECTIVE: The objective is to measure the presence, distribution and density of CoA in the lateral temporal lobes of patients with DRTLE and focal cortical dysplasia (FCD), also examining how CoA density may be linked to demographic and clinical traits. METHODS: Resected tissue from 35 patients was analysed. CoA density was assessed with a semi-quantitative scale according to the criteria established by Cherian et al. RESULTS: Presence of CoA in the neocortex of 9 patients was associated with hippocampal sclerosis (FCD type iiia, 7 cases), disembryoplastic neuroepithelial tumour (FCD type iiib, 1 case), and cavernous angioma (FCD type iiic, 1 case). The meningeal surface (MS) was involved in all cases, and 8 cases displayed CoA in the cerebral parenchyma (white matter) and around blood vessels. CoA density on the MS showed a negative correlation with age at seizure onset (r = -0.828, P<.05) and a positive correlation with disease duration (r = 0.678, P<.05) but not with postoperative clinical outcome. CONCLUSIONS: Patients with DRTLE and a primary lesion (hippocampal sclerosis, tumour, vascular malformation) associated with mild FCD were shown to have CoA deposits in the neocortex. No association was found between presence of CoA and clinical outcome one year after surgery.

Estudio prospectivo, abierto, controlado y aleatorizado de clobazam frente a carbamacepina en pacientes con crisis frecuentes de epilepsia rolándica / A prospective, open, controlled and randomised study of clobazam versus carbamazepine in patients with frequent episodes of rolandic epilepsy

Resumen. Introducción. No existen estudios controlados, aleatorizados y con régimen de dosificación flexibles en niños con epilepsia rolándica, por lo que la terapia es aún empírica. Objetivo. Evaluar la eficacia y la tolerabilidad del clobazam (CLB) comparado con la carbamacepina (CBZ) en la epilepsia rolándica. Pacientes y métodos. Estudio prospectivo, abierto, controlado, aleatorizado de CBZ frente a CLB en niños con epilepsia rolándica con seguimiento durante dos años. Se aleatorizaron 45 pacientes y terminaron el estudio 38 sujetos. Se indicó un régimen de dosificación flexible. Se evaluó el control de crisis, el rendimiento escolar, el comportamiento, la adherencia al tratamiento, el grado de satisfacción de los padres y el perfil de efectos adversos. Resultados. Ambos medicamentos fueron igualmente eficaces para controlar las crisis (el 94,1% de pacientes con CLB y el 100% con CBZ estaban libres de crisis al finalizar el estudio; p = 0,26). El CLB logró controlar las crisis más tempranamente (33,3 ± 45 frente a 48,2 ± 72,3 días; p < 0,05) y tuvo menos efectos adversos que la CBZ (aparecieron efectos adversos en tres pacientes con CLB y ocho con CBZ; p = 0). En dos pacientes en régimen de CBZ, las crisis empeoraron y junto con ello aparecieron complicaciones cognitivoconductuales. Conclusiones. La CBZ es un medicamento eficaz en la epilepsia rolándica, pero puede asociarse a un empeoramiento de las crisis, así como a déficit cognitivos y conductuales. El CLB en monoterapia parece ser un fármaco eficaz y mejor tolerado en este tipo de epilepsia (AU)

Summary. Introduction. To date no controlled, randomised studies with flexible dose regimens have been conducted in children with rolandic epilepsy, and therapy is therefore still empirical. Aim. To evaluate the effectiveness and safety of clobazam (CLB) compared with that of carbamazepine (CBZ) in rolandic epilepsy. Patients and methods. A prospective, open, controlled and randomised study was carried out to compare CBZ and CLB in children with rolandic epilepsy with a follow-up over a twoyear period. A random sample of 45 patients was taken and 38 of them finished the study. A flexible dose regimen was indicated. Control of seizures, academic performance, behaviour, adherence to treatment, parents’ degree of satisfaction and side effect profiles were all evaluated. Results. Both drugs were equally effective at controlling seizures (94.1% of patients with CLB and 100% of those with CBZ were free of seizures on ending the study; p = 0.26). CLB controlled seizures earlier (33.3 ± 45 days versus 48.2 ± 72.3; p < 0.05) and had fewer side effects than CBZ (side effects appeared in three patients with CLB and in eight of those on CBZ; p = 0). In two of the patients taking CBZ, the seizures got worse and a series of cognitive-behavioural complications also appeared. Conclusions. CBZ is an effective drug in rolandic epilepsy, but it may be associated with exacerbation of seizures as well as with cognitive-behavioural impairment. CLB in monotherapy seems to be an effective and better tolerated drug in this kind of epilepsy (AU)

[A prospective, open, controlled and randomised study of clobazam versus carbamazepine in patients with frequent episodes of Rolandic epilepsy]. / Estudio prospectivo, abierto, controlado y aleatorizado de clobazam frente a carbamacepina en pacientes con crisis frecuentes de epilepsia rolándica.

INTRODUCTION: To date no controlled, randomised studies with flexible dose regimens have been conducted in children with rolandic epilepsy, and therapy is therefore still empirical. AIM: To evaluate the effectiveness and safety of clobazam (CLB) compared with that of carbamazepine (CBZ) in rolandic epilepsy. PATIENTS AND METHODS: A prospective, open, controlled and randomised study was carried out to compare CBZ and CLB in children with rolandic epilepsy with a follow-up over a two-year period. A random sample of 45 patients was taken and 38 of them finished the study. A flexible dose regimen was indicated. Control of seizures, academic performance, behaviour, adherence to treatment, parents' degree of satisfaction and side effect profiles were all evaluated. RESULTS: Both drugs were equally effective at controlling seizures (94.1% of patients with CLB and 100% of those with CBZ were free of seizures on ending the study; p = 0.26). CLB controlled seizures earlier (33.3 +/- 45 days versus 48.2 +/- 72.3; p < 0.05) and had fewer side effects than CBZ (side effects appeared in three patients with CLB and in eight of those on CBZ; p = 0). In two of the patients taking CBZ, the seizures got worse and a series of cognitive-behavioural complications also appeared. CONCLUSIONS: CBZ is an effective drug in rolandic epilepsy, but it may be associated with exacerbation of seizures as well as with cognitive-behavioural impairment. CLB in monotherapy seems to be an effective and better tolerated drug in this kind of epilepsy.

[Pathological neocortical findings in patients with medication-resistant medial temporal lobe epilepsy submitted to surgery]. / Hallazgos patológicos neocorticales en pacientes con epilepsia del lóbulo temporal medial farmacorresistente sometidos a cirugía.

INTRODUCTION: The dual pathology consisting of hippocampal sclerosis plus focal cortical dysplasia (FCD) is often reported in patients with medication-resistant medial temporal lobe epilepsy (MTLE). AIMS: To determine the histopathological changes that take place in the neocortex of patients with medication-resistant MTLE submitted to surgery and to evaluate the relation between the histopathological changes, pathological background and the clinical course of patients who had received surgical treatment. MATERIALS AND METHODS: Tissue obtained by en bloc resection from the neocortex of 18 patients with MTLE refractory to medical treatment was processed histologically and a tailored temporal lobectomy was performed with electrocorticography. RESULTS: Dual pathology was diagnosed in 13 patients (72.2%). Imaging studies confirmed the existence of mesial sclerosis of the temporal in 100% of cases and there was no evidence of neocortical lesions. Histologically, 46.15% and 38.46% of the patients were diagnosed as belonging to FCD type 1a and FCD type 1b, respectively. Only one patient presented FCD type 2a. A statistically significant relation was found between the presence of dual pathology and the existence of an early precipitating injury (p = 0.04). One year after surgery, 72.7% (8/11) patients with dual pathology were classified as belonging to Engel class I. CONCLUSIONS: In patients with MTLE there are microscopic FCD-type alterations in the neocortex. There is an association between these alterations and the existence of an initial precipitating injury. Complete resection of the epileptogenic area, which is guaranteed by the lobectomy tailored by electrocorticography, allows patients to enjoy a favourable post-surgical progression one year after surgery.

[Volumetric measurement and digital electroencephalography in patients with medication-resistant medial temporal lobe epilepsy submitted to surgery]. / Volumetria y electroencefalografía digital en pacientes con epilepsia del lobulo temporal medial farmacorresistente sometidos a cirugía.

AIM: To assess the value of volumetric measurement by means of magnetic resonance imaging (MRI) and interictal electroencephalogram (EEG) in pre- and post-operative assessment of patients with medication-resistant medial temporal lobe epilepsy (MTLE) who were submitted to surgery. PATIENTS AND METHODS: We evaluated 12 volumetric studies carried out using MRI and 24 digital EEG records for six patients suffering from complex partial seizures that were resistant to medical treatment and had their origin in the temporal lobe. A volumetric analysis was performed using MRI to study the epileptogenic region and the frequencies at which interictal epileptiform discharges (IED/minute) appeared before, at six months and at one year after surgery were calculated; a correlation was observed between the volumetric analysis and the irritative and epileptogenic region. RESULTS: The volumes of both the ipso and contralateral hippocampuses were smaller in comparison to the increased frequency of the IED in the mesial regions. The inferior temporal lobes and the parahippocampal cortex have reduced volumes ipsolateral to the epileptogenic region. At six months after performing the temporal lobectomy, the IED frequency decreased with respect to the pre-operative IED. A negative correlation was found between the resected volume of the parahippocampal cortex and the inferior temporal lobe, and the post-operative IED frequency at one year. CONCLUSIONS: In patients with medication resistant MTLE the volumes of other structures in the medial temporal lobe are diminished, in addition to the hippocampus, and they are seen to have a smaller volume on the side that is ipsolateral to the epileptogenic region. There is a relation between the volume of the resected hippocampus and the post-operative IED frequency in patients with MTLE who successfully underwent a temporal lobectomy. Volumetric analysis of the epileptogenic lesion using MRI provides localising information that is valuable in the pre-operative assessment of patients with medication resistant MTLE who are submitted to surgery.

Hallazgos patológicos neocorticales en pacientes con epilepsia del lóbulo temporal medial farmacorresistente sometidos a cirugía / Pathological neocortical findings in patients with medication-resistant medial temporal lobe epilepsy submitted to surgery

La patología dual compuesta por esclerosis hipocampal y displasia cortical focal (DCF) se describecon frecuencia en pacientes con epilepsia del lóbulo temporal medial (ELTM) farmacorresistente. Objetivos. Determinar los cambios histopatológicos en la neocorteza de pacientes con ELTM farmacorresistente sometidos a cirugía y evaluar la relación entre los cambios histopatológicos, los antecedentes patológicos y la evolución clínica en los pacientes operados. Materialesy métodos. Se procesó histológicamente el tejido resecado en bloque (neocorteza) de 18 pacientes con ELTM refractaria a tratamiento médico, y se les realizó lobectomía temporal ajustada por electrocorticografía. Resultados. Se diagnóstico patología dual en 13 pacientes (72,2%). Los estudios imagenológicos confirmaron en el 100% de los casos la esclerosis mesialdel temporal y no existieron evidencias de lesión neocortical. Histológicamente, el 46,15% y el 38,46% de los pacientes fueron diagnosticados como DCF tipo 1a y DCF tipo 1b, respectivamente. Sólo un paciente presentó DCF tipo 2a. Se demostró una relación estadísticamente significativa entre la presencia de patología dual y la existencia de una daño precipitante inicial (p = 0,04). El 72,7% (8/11) de los pacientes con patología dual un año después de la cirugía se clasificó en la clase Ide Engel. Conclusiones. En los pacientes con ELTM existen alteraciones microscópicas en la neocorteza del tipo DCF. Estas alteraciones se asocian a la existencia de un daño precipitante inicial. La resección completa de la zona epileptogénica, garantizadapor la lobectomía ajustada por electrocorticografía, permite una buena evolución posquirúrgica un año después de la cirugía

The dual pathology consisting of hippocampal sclerosis plus focal cortical dysplasia (FCD) is oftenreported in patients with medication-resistant medial temporal lobe epilepsy (MTLE). Aims. To determine the histopathological changes that take place in the neocortex of patients with medication-resistant MTLE submitted to surgery and to evaluate the relation between the histopathological changes, pathological background and the clinical course of patients whohad received surgical treatment. Materials and methods. Tissue obtained by en bloc resection from the neocortex of 18 patients with MTLE refractory to medical treatment was processed histologically and a tailored temporal lobectomy was performed with electrocorticography. Results. Dual pathology was diagnosed in 13 patients (72.2%). Imaging studies confirmed the existenceof mesial sclerosis of the temporal in 100% of cases and there was no evidence of neocortical lesions. Histologically, 46.15% and 38.46% of the patients were diagnosed as belonging to FCD type 1a and FCD type 1b, respectively. Only one patient presented FCD type 2a. A statistically significant relation was found between the presence of dual pathology and the existenceof an early precipitating injury (p = 0.04). One year after surgery, 72.7% (8/11) patients with dual pathology were classified as belonging to Engel class I. Conclusions. In patients with MTLE there are microscopic FCD-type alterations in the neocortex.There is an association between these alterations and the existence of an initial precipitating injury. Complete resection of the epileptogenic area, which is guaranteed by the lobectomy tailored by electrocorticography, allows patients to enjoy a favourable post-surgical progression one year after surgery

Volumetría y electroencefalografía digital en pacientes con epilepsia del lóbulo temporal medial farmacorresistente sometidos a cirugía / Volumetric measurement and digital electroencephalography in patients with medications-resistant medial temporal lobe epilepsy submitted to surgery

Evaluar la contribución de la volumetría mediante resonancia magnética (RM) y el electroencefalograma(EEG) interictal en la evaluación pre y posquirúrgica de pacientes con epilepsia del lóbulo temporal medial (ELTM) farmacorresistente sometidos a cirugía. Pacientes y métodos. Se evaluaron 12 estudios volumétricos por RM y 24 registros de EEG digital correspondientes a seis pacientes con crisis parciales complejas refractarias a tratamiento médico de origen temporal.Se realizó el análisis volumétrico por RM, para el estudio de la zona epileptogénica, y se calculó la frecuencia de aparición de descargas epileptiformes interictales (DEI/minuto) antes, a los seis meses y al año de la cirugía, y se correlacionóel análisis volumétrico con la zona irritativa y epileptogénica. Resultados. Los volúmenes de los hipocampos tanto ipsi comocontralaterales están disminuidos de tamaño en comparación con el aumento de la frecuencia DEI en las zonas mesiales. Los lóbulos temporales inferiores y la corteza parahipocámpica se encontraron disminuidos de volumen ipsilaterales a la zona epileptogénica. La frecuencia de DEI disminuye a los seis meses de realizada la lobectomía temporal respecto a las DEI prequirúrgica.Se encontró correlación negativa entre el volumen resecado de la corteza parahipocámpica y el lóbulo temporal inferior con la frecuencia DEI posquirúrgica al año. Conclusiones. En pacientes con ELTM farmacorresistente se encuentrandisminuidos los volúmenes de otras estructuras del lóbulo temporal medial, además del hipocampo, y se constata un menor volumen de éstas, en el lado ipsilateral a la zona epileptogénica. El volumen de hipocampo resecado se relaciona con la frecuenciade DEI posquirúrgica de los pacientes con ELTM sometidos a lobectomía temporal exitosa. El análisis volumétricomediante RM de la lesión epileptogénica aporta información localizadora de utilidad en la evaluación prequirúrgica de pacientes con ELTM farmacorresistente sometidos a cirugía

To assess the value of volumetric measurement by means of magnetic resonance imaging (MRI) and interictalelectroencephalogram (EEG) in pre- and post-operative assessment of patients with medication-resistant medial temporal lobe epilepsy (MTLE) who were submitted to surgery. Patients and methods. We evaluated 12 volumetric studies carried out using MRI and 24 digital EEG records for six patients suffering from complex partial seizures that were resistant to medicaltreatment and had their origin in the temporal lobe. A volumetric analysis was performed using MRI to study the epileptogenic region and the frequencies at which interictal epileptiform discharges (IED/minute) appeared before, at six months and at oneyear after surgery were calculated; a correlation was observed between the volumetric analysis and the irritative and epileptogenic region. Results. The volumes of both the ipso and contralateral hippocampuses were smaller in comparison tothe increased frequency of the IED in the mesial regions. The inferior temporal lobes and the parahippocampal cortex havereduced volumes ipsolateral to the epileptogenic region. At six months after performing the temporal lobectomy, the IED frequency decreased with respect to the pre-operative IED. A negative correlation was found between the resected volume of the parahippocampal cortex and the inferior temporal lobe, and the post-operative IED frequency at one year. Conclusions. Inpatients with medication resistant MTLE the volumes of other structures in the medial temporal lobe are diminished, in addition to the hippocampus, and they are seen to have a smaller volume on the side that is ipsolateral to the epileptogenic region. There is a relation between the volume of the resected hippocampus and the post-operative IED frequency in patientswith MTLE who successfully underwent a temporal lobectomy. Volumetric analysis of the epileptogenic lesion using MRI provides localising information that is valuable in the pre-operative assessment of patients with medication resistant MTLE who are submitted to surgery

[Video-EEG evaluation complemented by spectral and EEG source analysis in patients with medication-resistant medial temporal lobe epilepsy]. / Evaluación videoelectroencefalográfica complementada con análisis espectral y de las fuentes generadoras del electroencefalograma en pacientes con epilepsia del lóbulo temporal medial resistente a los fármacos.

AIM: To evaluate the value of prolonged video-electroencephalographic (video-EEG) monitoring complemented with spectral and EEG source analysis in identifying the epileptogenic area in patients with medial temporal lobe epilepsy who are candidates for non-lesional resective surgery. PATIENTS AND METHODS: The electrographic patterns during the onset of seizures were evaluated in over 667 seizures from 41 patients with a clinical diagnosis of medication-resistant partial epilepsy. Analyses were performed using Harmonie software and variable resolution electrical tomography (VARETA). RESULTS: Video-EEG was used to determine that 53.6% of the patients evaluated suffered complex partial seizures of a temporal origin; these were characterised by having an average frequency of 5.56 +/- 1.56 Hz, while the non-temporal seizures displayed a frequency within the range 9.17 +/- 3.32 Hz. The topographic location of the dominant ictal frequency during the period of maximum spectral energy in patients with temporal lobe epilepsy enabled us to draw a distinction between a group of patients with mesial seizures and those with non-mesial seizures that exceeded the number that was determined by visual inspection of the EEG, that is, 78.9 versus 47.3%, respectively. There was a 100% coincidence between the area where the seizures began as defined by surface EEG complemented with spectral analysis, the generator of this activity as defined by VARETA and the epileptogenic region. CONCLUSIONS: The localising information provided by video-EEG complemented with spectral and EEG source analysis allows for non-invasive location of the epileptogenic region in patients with medial temporal lobe epilepsy even when structural imaging studies show an absence or bilaterality of abnormalities.

Evaluación videoelectroencefalográfica complementada con análisis espectral y de las fuentes generadoras del electroencefalograma en pacientes con epilepsia del lóbulo temporal medial resistente a los fármacos / Video-EEG evaluation complemented by spectral and EEG source analysis in patients with medication-resistant medal temporal lobe epilepsy

Objetivo. Evaluar la contribución de la monitorización prolongada videoelectroencefalográfica (video-EEG) complementada con análisis espectral y de las fuentes generadoras del electroencefalograma (EEG) en la identificación de la zona epileptogénica de pacientes con epilepsia del lóbulo temporal medial candidatos a cirugía resectiva no lesional. Pacientes y métodos. Se evaluaron los patrones electrográficos del inicio ictal en más de 667 crisis correspondientes a 41 pacientes con diagnóstico clínico de epilepsia parcial resistente a fármacos. Para el análisis se utilizaron el software Harmonie y la tomografía eléctrica de resolución variable (VARETA). Resultados. Mediante video-EEG se determinó que el 53,6% de los pacientes evaluados presentaba crisis parciales complejas de origen temporal; éstas se caracterizaron por una frecuencia media de 5,56 ± 1,56 Hz, mientras que las no temporales presentaron una frecuencia en el rango de 9,17 ± 3,32 Hz. La localización topográfica de la frecuencia ictal dominante durante el período de energía espectral máxima en los pacientes con epilepsia del lóbulo temporal permitió distinguir a un grupo de pacientes con crisis mesiales y otros no mesiales que superaron el número determinado por la inspección visual del EEG: un 78,9 frente a un 47,3%, respectivamente. Se evidenció una coincidencia del 100% entre la zona de inicio ictal definida por EEG de superficie complementada con análisis espectral, el generador de esta actividad definido por VARETA y la zona epileptogénica. Conclusiones. La información localizadora aportada por el video-EEG complementada con el análisis espectral y de las fuentes del EEG permite localizar de forma no invasiva la zona epileptogénica en pacientes con epilepsia del lóbulo temporal medial aun cuando los estudios imaginológicos estructurales evidencian ausencia o bilateralidad de anomalías

Aim. To evaluate the value of prolonged video-electroencephalographic (video-EEG) monitoring complemented with spectral and EEG source analysis in identifying the epileptogenic area in patients with medial temporal lobe epilepsy who are candidates for non-lesional resective surgery. Patients and methods. The electrographic patterns during the onset of seizures were evaluated in over 667 seizures from 41 patients with a clinical diagnosis of medication-resistant partial epilepsy. Analyses were performed using Harmonie software and variable resolution electrical tomography (VARETA). Results. Video- EEG was used to determine that 53.6% of the patients evaluated suffered complex partial seizures of a temporal origin; these were characterised by having an average frequency of 5.56 ± 1.56 Hz, while the non-temporal seizures displayed a frequency within the range 9.17 ± 3.32 Hz. The topographic location of the dominant ictal frequency during the period of maximum spectral energy in patients with temporal lobe epilepsy enabled us to draw a distinction between a group of patients with mesial seizures and those with non-mesial seizures that exceeded the number that was determined by visual inspection of the EEG, that is, 78.9 versus 47.3%, respectively. There was a 100% coincidence between the area where the seizures began as defined by surface EEG complemented with spectral analysis, the generator of this activity as defined by VARETA and the epileptogenic region. Conclusions. The localising information provided by video-EEG complemented with spectral and EEG source analysis allows for non-invasive location of the epileptogenic region in patients with medial temporal lobe epilepsy even when structural imaging studies show an absence or bilaterality of abnormalities

[Contribution of thalamic somatosensory evoked potentials to stereotaxic thalamometry]. / Contribución de los potenciales somatosensoriales talámicos a la talamotomía estereotáxica.

INTRODUCTION: In order to use short latency somatosensory thalamic evoked potentials (PES) to locate therapeutic targets in functional surgery, thalamic PES were recorded during stereotactic thalamotomy in 25 patients with Parkinson's disease, using a concentric bipolar semi-micro-electrode, 4 mm in diameter. In the 72 trajectories planned. 628 registers were made, obtaining 314 PES in 55 trajectories. These recordings were divided into 5 groups, according to the electrical variables evaluated in each case (absolute latency, inter-peak latency, absolute amplitude and number of phases). MATERIAL AND METHODS: The electrophysiological characteristics of the PES groups obtained, and the spatial representation of these in a tridimensional system of coordinates, is shown. We analyze the sequence of the groups of potentials in each of the trajectories followed. CONCLUSIONS: We consider that the limit between adjacent nuclear edges, ventral intermediate (Vim)-ventro-caudal (Vc), may be represented by the transition of potentials in group 1 to potentials in group 4 and/or potentials of group 3 to those of group 2. This study shows that thalamic PES are useful for locating targets during stereotactic thalamotomy.

Contribución de los potenciales somatosensoriales talámicos a la talamotomía estereotáxica / Contribution of the thalamic somatosensory evoked potentials to stereotactic thalamotomy

Introducción. En un esfuerzo por utilizar los potenciales evocados somatosensoriales (PES) talámicos de corta latencia, como localizadores de blancos terapéuticos en la cirugía funcional, se registraron PES talámicos durante la talamotomía estereotáxica de 25 pacientes parkinsonianos, utilizando un semimicroelectrodo bipolar concéntrico de 0,4 mm de diámetro. A lo largo de las 72 trayectorias planificadas, se realizaron 628 registros obteniéndose 314 PES en 55 trayectorias. Estos registros se dividieron en cinco grupos, atendiendo a las variables eléctricas evaluadas para cada uno de ellos (latencia absoluta, latencia interpico, amplitud absoluta y número de fases). Material y métodos. Se muestra la caracterización electrofisiológica de los grupos de PES obtenidos, y la representación espacial de los mismos en un sistema de coordenadas tridimensional. Analizamos la secuencia de los grupos de potenciales en cada una de las trayectorias realizadas. Conclusiones. Planteamos que el límite entre bordes nucleares adyacentes ventral intermedio (Vim)-ventrocaudal (Vc) puede estar representado por la transición de potenciales del grupo 1 a potenciales del grupo 4 y/o de potenciales del grupo 3 a los del grupo 2. Con este estudio se demuestra la utilidad de los PES talámicos en la localización de los blancos durante la talamotomía estereotáxica