Résumé
Resumen Introducción. La comprensión del lenguaje está determinada por diversos procesos, entre los que se encuentra el reconocimiento léxico. Según el modelo conexionista, este reconocimiento se genera por activación mediante el emparejamiento de la información acumulada y por la inhibición de las entradas léxicas que compiten por activación. Objetivo. Determinar las diferencias temporales y espaciales de procesamiento entre las incongruencias léxicas semánticamente relacionadas a un contexto lingüístico oracional y las no relacionadas a través de mediciones electrofisiológicas de potenciales relacionados a eventos (PRE). Materiales y métodos. Se realizó la medición de los PRE en 10 sujetos sanos por medio de un paradigma de 240 oraciones en español agrupadas de la siguiente manera: 80 oraciones congruentes, 80 con incongruencias dentro del campo léxico y 80 con incongruencias fuera del campo léxico. Resultados. Se observó una diferencia estadística en la latencia de aparición del componente N400 entre las dos condiciones. Por su parte, se encontró una mayor activación del precúneo, del giro orbitofrontal, del giro angular y del giro supramarginal en la condición de incongruencia fuera del campo léxico. Conclusión. Se identificaron diferencias temporales y espaciales (activación del precúneo, del giro orbitofrontal, del giro angular y del giro supramarginal) entre el procesamiento de las incongruencias léxicas y no léxicas.
Abstract Introduction: Language understanding depends on several processes, including lexical recognition. According to the connectionist model, this recognition is generated by activation through the matching of accumulated information and by the inhibition of lexical entries that compete for activation. Objective: To determine, through electrophysiological measurements of event-related potentials (ERP), temporal and spatial processing differences between lexical inconsistencies semantically related to a sentence linguistic context and those that are unrelated. Materials and methods: ERPs were measured in 10 healthy subjects by means of a 240 Spanish sentences paradigm grouped as follows: 80 congruent sentences, 80 sentences with lexical incongruities, and 80 with non-lexical incongruities. Results: A statistical difference was found in the latency of appearance of the N400 component between both conditions. On the other hand, a greater activation of the precuneus, the orbitofrontal gyrus, the angular gyrus and the supramarginal gyrus was observed in the non-lexical incongruity condition. Conclusion: There are temporal and spatial (activation of the precuneus, the orbitofrontal gyrus, the angular gyrus and the supramarginal gyrus) differences between the processing of lexical inconsistencies and the processing of non-lexical inconsistencies.
Résumé
Resumen La Enfermedad de Parkinson (EP) es una patología progresiva con degeneración del sistema dopaminérgico nigro-estriatal con disfunción de proyecciones frontales que genera alteraciones en funciones ejecutivas. Esta condición debería afectar particularmente la capacidad de evocar unidades léxicas y recuperarlas desde la memoria de largo plazo; no obstante, si bien se cuenta con datos acerca de este comportamiento, aún es necesario determinar qué subcomponentes del lenguaje se ven afectados a fin de comprender con mayor especificidad tanto la patología como su manifestación lingüística. En este marco, el objetivo del presente estudio consistió en describir el rendimiento en tareas de fluidez verbal de tipo fonológica, morfosintáctica, semántica y sus combinaciones en participantes con enfermedad de Parkinson (EP). Para ello, se realizó un estudio transversal con 42 sujetos, agrupados en Adulto Mayor Sano (AMS; n = 23) y Adulto Mayor Diagnosticado con EP (EP; n = 19). Cada sujeto realizó un total de 15 tareas de fluidez verbal en las que debió evocar la mayor cantidad de unidades léxicas en 60 segundos, las que fueron, además, medidas en intervalos de 15 segundos. Los resultados permitieron observar diferencias estadísticamente significativas en las subtareas de tipo fonológica de fonema excluido, categoría gramatical, relaciones semánticas y de combinación campo léxico y fonema inicial. Estos datos parecen indicar que los sujetos con EP muestran un rendimiento significativamente inferior en tareas que exigen alto control inhibitorio, dado que las subtareas que combinan niveles de la lengua implican evocación e inhibición.
Abstract Parkinson's disease (PD) is a progressive pathology that implies a degeneration of the nigro-striatal dopaminergic system with dysfunction of frontal projections, which generates alterations in executive functions, specifically in sustained attention, working memory, planning and cognitive flexibility, among others. In fact, this pathology has repercussions on several language components. Particularly, there is evidence indicating that the ability to evoke lexical units and recover them from long-term memory or lexicon is affected. Although these types of tasks seem to be sensitive for the detection of Parkinson's disease, both in patients with mild cognitive impairment and another with dementia, it is still necessary to have evidence to determine which specific subcomponents of the language are affected, since this will allow us to understand with more specificity both the pathology and its linguistic manifestation, at the same time as to design therapies by support teams for this type of patients. In this context, verbal fluency (VF) tests could contribute to obtaining this type of information. VF is defined as an executive function that involves the access and evocation of clusters of linguistic information, and that is related to attention and working memory processes, since it is initiated by the activation of information groups through specific search strategies Moreover, it involves various linguistic functions, such as the naming, and executive functions of planning, working memory and initiation of behavior. Specifically, this type of task consists of requesting the subject under evaluation to nominate the largest number of elements of a lexical category according to a specific rule for a specific time, such as names of countries or word containing the phoneme / f /. From there, it has been observed which associated language areas are activated: ventral-anterior lower frontal gyrus in categorical tasks, dorsal-posterior lower frontal gyrus in phonological tasks and parietal areas of the right hemisphere that are associated with executive functions and attentional processes in tasks of greater complexity. Within this framework, the aim of the present study was to describe the performance in tasks of verbal fluency of a phonological, morph syntactic, semantic type and their combinations in participants diagnosed with Parkinson's disease (PD). For this, a cross-sectional study was conducted with 42 subjects, grouped as healthy older adults (AMS; n = 23) and older adults diagnosed with PD without dementia (EP; n = 19). The subjects of the control group had a mean age of 66 years (SD = 6.9) and 11.5 years of schooling (SD = 3.1); on the other hand, subjects with PD had a mean age of 71 years (SD = 8.03) and 13.2 years of schooling (SD = 3.9). Each subject performed a total of 15 verbal fluency tasks, in which he had to evoke the greatest number of lexical units in 60 seconds, which were also measured in intervals of 15 seconds. The results shown statistically significant differences in the sub-tasks of the phonemic type of excluded phoneme (FVFLE1: p = .012 and FVFLE2: p = .047), morph syntactic adjective categories (FVM2: p = .005), in the synonymy relationships (FVS3: p = .028) and lexical field and phonology (FVSF: p = .004). These data seem to indicate that subjects with Parkinson's disease show significantly lower performance in tasks that require high inhibitory control, since subtasks that combine tongue levels involve evocation and inhibition at the same time. These results are consistent with the pathophysiology of the condition.