[Event related brain potentials and imageability effect in the semantic processing]. / Potenciales evocados cerebrales asociados al efecto de imaginabilidad en el procesamiento semántico.

INTRODUCTION: Event-related brain potentials (ERPs) are a useful measure of the brain activity underlying linguistic processing. They can also be used to study cognitive/linguistic impairment in different neurological diseases. To do this, it is necessary to know which electrophysiological components are related to relevant linguistic parameters, and the characteristics of these components. One of these parameters is the dimension of concrete-abstract or imageability. AIM: To find electrophysiological evidence for differential processing of concrete vs abstract verbal material, in the absence of brain damage. SUBJECTS AND METHODS: The short, semantically congruent sentences used were made up of high or low imageability (HI/LI) verbs followed by HI/LI complements. We also manipulated close probability in the case of the complement. Sentences were shown word by word and participants were asked to make an imageability judgement. Electrophysiological recording during verb and final complement were analysed in ten subjects. RESULTS: Electrophysiological recording obtained during verb presentation show an imageability effect starting at 350 ms (especially in the N400 component) with no differential scalp distribution. There is a similar tendency in the recordings of final complements, although differences in imageability are not statistically significant. CONCLUSIONS: These results suggest the existence of an imageability effect in the ERPs associated with semantic processing in semantically congruent sentences and that this effect is produced when the verb is presented.

Potenciales evocados cerebrales asociados al efecto de imaginabilidad en el procesamiento semántico / Event related brain potentials and imageability effect in the semantic processing

Introducción. Los potenciales evocados cerebrales son indicadores útiles de la actividad cerebral que subyace al procesamiento lingüístico. Pueden, además, emplearse en el estudio de las alteraciones cognitivas/lingüísticas en diferentes patologías neurológicas. Para ello, es necesario conocer los posibles correlatos electrofisiológicos asociados a parámetros relevantes en el procesamiento lingüístico y las características de sus componentes. Uno de estos parámetros es la dimensión concreto-abstracto o imaginabilidad. Objetivo. Obtener evidencias electrofisiológicas de un procesamiento diferencial de material verbal concreto frente a abstracto en ausencia de daño cerebral. Sujetos y métodos. Se utilizaron frases cortas de tipo verbo-complemento, semánticamente congruentes, de alta y baja imagen (AI, BI), constituidas por verbos de AI o BI, situados en mitad de la frase, y complementos de AI o BI, respectivamente. Se manipuló, además, la probabilidad de compleción del complemento. Las frases se presentaron palabra a palabra y se solicitó a los participantes un juicio de imaginabilidad. Se analizaron los registros electrofisiológicos contingentes a la aparición del verbo y del complemento final en 10 sujetos. Resultados. Los registros obtenidos durante la presentación del verbo nos muestran un efecto de la imaginabilidad a partir de los 350 ms, especialmente en el componente N400, sin diferencias en su distribución. En los registros de los complementos finales de frase, si bien se observa una tendencia similar, las diferencias en imaginabilidad no son estadísticamente significativas. Conclusiones. Nuestros resultados indican que existe un efecto de la imaginabilidad en los potenciales evocados cerebrales asociados al procesamiento semántico de frases semánticamente congruentes, y que se produce desde la presentación del verbo (AU)

ntroduction. Event-related brain potentials (ERPs) are a useful measure of the brain activity underlying linguistic processing. They can also be used to study cognitive/linguistic impairment in different neurological diseases. To do this, it is necessary to know which electrophysiological components are related to relevant linguistic parameters, and the characteristics of these components. One of these parameters is the dimension of concrete-abstract or imageability. Aim. To find electrophysiological evidence for differential processing of concrete vs abstract verbal material, in the absence of brain damage. Subjects and methods. The short, semantically congruent sentences used were made up of high or low imageability (HI/LI) verbs followed by HI/LI complements. We also manipulated cloze probability in the case of the complement. Sentences were shown word by word and participants wereasked to make an imageability judgement. Electrophysiological recording during verb and final complement were analysed in ten subjects. Results. Electrophysiological recording obtained during verb presentation show an imageability effect starting at 350 ms (especially in the N400 component) with no differential scalp distribution. There is a similar tendency in the recordings of final complements, although differences in imageability are not statistically significant. Conclusions. These results suggest the existence of an imageability effect in the ERPs associated with semantic processing in semantically congruent sentences and that this effect is produced when the verb is presented (AU)

[Multiple sclerosis and depression]. / Esclerosis multiple y depresion.

INTRODUCTION: Depression has frequently been reported in multiple sclerosis. However, prevalence rates must be interpreted in the light of the conceptual and methodological limitations of these studies. Depression has traditionally been associated with response to the diagnosis of this disease, the presence of physical and cognitive limitations, the damage of specific neural systems and inmunomodulatory therapy. AIMS: To assess the evolution of emotional state and its relationship with motor and cognitive slowness, in relapsing remitting patients with minimal levels of neurological disability. PATIENTS AND METHODS: Data are reported for 35 patients with relapsing remitting multiple sclerosis, 27 treated with interferons and 8 without interferon treatment. Mood disturbance (Beck Depression Inventory, BDI), physical disability (Kurtzke Expanded Disability Status Scale, EDSS) and speed of information processing (reaction times) were assessed. The first testing was carried out before the start of treatment and the second testing one year later. RESULTS AND CONCLUSIONS: The group of patients showed a total BDI score indicative of minimal depression associated with items expressing performance difficulties and somatic complaints. Emotional state was not related to physical disability but was related to processing speed measures. A significant improvement of depression was observed after one year of treatment with inmunomodulatory therapy.

Esclerosis múltiple y depresión / Multiple sclerosis and depression

Introducción. La presencia de depresión en la esclerosis múltiple se ha descrito frecuentemente. Sin embargo, la prevalencia de este trastorno debe interpretarse teniendo en cuenta las limitaciones conceptuales y metodológicas de los estudios realizados. Habitualmente, la depresión se ha relacionado con la respuesta al diagnóstico de la enfermedad, la presencia de limitaciones físicas y cognitivas, la afectación de determinados sistemas neurales y la aplicación de diversos tratamientos inmunomoduladores. Objetivos. Evaluar el estado emocional en pacientes de curso remitente-recidivante con un nivel de discapacidad mínimo, así como su evolución y la relación con el enlentecimiento cognitivo y motor. Pacientes y métodos. Se estudiaron 35 pacientes con esclerosis múltiple remitenterecidivante, 27 tratados con interferones y ocho sin tratamiento. Se valoró el estado de ánimo (inventario de depresión de Beck, BDI), la discapacidad física (escala del estado de disfunción ampliada de Kurtzke, EEDA) y la velocidad de procesamiento (tiempos de reacción). La primera exploración se realizó paralelamente al inicio del tratamiento y la segunda, un año después. Resultados y conclusiones. El grupo de pacientes mostró una puntuación total en el BDI indicativa de depresión leve asociada a los ítems que expresan dificultades de ejecución y quejas somáticas. El estado de ánimo no se relacionaba con el nivel de afectación neurológica, aunque sí con las medidas de velocidad de procesamiento. Se produjo una mejoría significativa en el estado de ánimo después de un año de tratamiento con agentes inmunomoduladores (AU)

Introduction. Depression has frequently been reported in multiple sclerosis. However, prevalence rates must be interpreted in the light of the conceptual and methodological limitations of these studies. Depression has traditionally been associated with response to the diagnosis of this disease, the presence of physical and cognitive limitations, the damage of specific neural systems and inmunomodulatory therapy. Aims. To assess the evolution of emotional state and its relationship with motor and cognitive slowness, in relapsing-remitting patients with minimal levels of neurological disability. Patients and methods. Data are reported for 35 patients with relapsing-remitting multiple sclerosis, 27 treated with interferons and 8 without interferon treatment. Mood disturbance (Beck Depression Inventory, BDI), physical disability (Kurtzke Expanded Disability Status Scale, EDSS) and speed of information processing (reaction times) were assessed. The first testing was carried out before the start of treatment and the second testing one year later. Results and conclusions. The group of patients showed a total BDI score indicative of minimal depression associated with items expressing performance difficulties and somatic complaints. Emotional state was not related to physical disability but was related to processing speed measures. A significant improvement of depression was observed after one year of treatment with inmunomodulatory therapy (AU)

[Friedreich's ataxia: analysis of magnetic resonance imaging parameters and their correlates with cognitive and motor slowing]. / Ataxia de Friedreich: análisis de parámetros de resonancia magnética y correlatos con el enlentecimiento cognitivo y motor.

INTRODUCTION: The heredodegenerative ataxias are a heterogeneous group of disorders affecting especially the cerebellum and its tracts. Magnetic resonance imaging (MRI) studies using quantitative methodology are scarce, particularly in Friedreich's ataxia (FA). On the other hand, slowness of information processing speed has been described in FA, but no empirical relation with MRI parameters has been established. OBJECTIVE: The aim of the present study was to quantitatively assess infra and supratentorial atrophy in patients with clinical diagnosis of FA and to establish the relationship with a information processing speed measure. PATIENTS AND METHODS: Twelve FA patients that fulfilled clinical diagnostic criteria and twelve control subjects were studied. A computerized system that differentiate reaction time and movement time, as well as a semiautomated technique of binarization and analysis of MRI were used. RESULTS: Patients showed a poorer performance in movement time and in reaction time. Analyzing the frequency of pathologic changes, vermal atrophy was present in 67% of the patients and cerebellar hemisphere atrophy in 50%. Only a minority of patients showed signs of supratentorial cerebral atrophy (17%). Statistically significant negative correlations were obtained between reaction time and the size of the cerebellum. CONCLUSIONS: Cerebellar hemisphere atrophy is a usual finding in FA, although vermal atrophy is more frequent. The relation between cerebellar atrophy and reaction time supports the claim about cerebellar involvement in the information processing and response speed.

Ataxia de Friedreich: análisis de parámetros de resonancia magnética y correlatos con el enlentecimiento cognitivo y motor / Friedreich's ataxia: analysis of magnetic resonance imaging parameters and their correlates with cognitive and motor slowing

Introducción. Las ataxias hereditarias degenerativas son un grupo heterogéneo de trastornos que afectan específicamente al cerebelo y los tractos cerebelosos. Son escasos en ellos los estudios cuantitativos de resonancia magnética (RM), especialmente en la ataxia de Friedreich (AF). Por otra parte, aunque se ha descrito un enlentecimiento en la velocidad de procesamiento en la AF, no se ha establecido su relación con los parámetros de RM. Objetivos. Valorar cuantitativamente las atrofias infratentorial y supratentorial en pacientes con diagnóstico clínico de AF y relacionarlas con una medida de velocidad de procesamiento. Pacientes y métodos. Seestudiaron 12 pacientes que cumplen los criterios clínicos de AF y 12 sujetos control. Utilizamos un sistema computarizado que analiza por separado los componentes mental y motor de los tiempos de reacción (TR) y un método semiautomatizado de digitalización y análisis de imágenes de RM. Resultados. Los pacientes muestran enlentecimiento, tanto mental como motor. En un análisis de la frecuencia de la presencia de atrofia, identificamos atrofia vermiana en un 67 por ciento de los casos, y afectación de los hemisferios cerebelosos en un 50 por ciento. Sólo una minoría de los casos (17 por ciento) mostró indicios de atrofia cerebral supratentorial. Se objetivaron correlaciones significativas, de signo negativo, entre los TR y el tamaño del cerebelo. Conclusiones. El vermis es la región más frecuentemente afectada, aunque la atrofia de los hemisferios cerebelosos es también un hallazgo común. La relación que existe entre la atrofia cerebelosa y los TR constituye una evidencia a favor de la participación del cerebelo en la velocidad de procesamiento y de respuesta (AU)

Introduction. Paroxysmal activity in medial temporal lobe epilepsy is originated in either hippocampal or parahippocampal regions. This activity can be directly recorded by foramen ovale electrodes. That paroxysmal activity will start from irritative or ictal areas. However, anatomo-functional relations between both regions are still debated. Objective. We describe a new physical very simple model which allows to directly analysis the anatomo-physiological relations between sources for interictal an ictal areas. Results. 1) The mathematical model allows to fit with minimum error and great precision the voltage sources originated from monopoles. 2) We can obtain this degree of precision with a matrix using an internodal distance of 0.1 mm (300 × 200 nodes) 3) Triplets of potentials with double sources -with equal or specially with inverse charges- have bigger error than monopolar charges. 4) Fitting real data obtained from a patient shows an error of 0.29 ± 0.17% for interictal and 0.54 ± 1.22 % and 2.84 ± 3.00 % for two seizures (mean ± SD) Conclusions. This model allows directly to know the relative anatomo-physiological relations between interictal and ictal sources in MTLE, which have a very important implications so for patho-physiological as therapeutics and outcome implications (AU)