Pilar Martín

Spanish language mapping using MEG: a validation study.

The purpose of the present study was to compare magnetoencephalography (MEG) data with the results of the intracarotid amytal procedure (IAP). Twenty-one native Spanish-speaking patients with intractable epilepsy underwent MEG language mapping. A subset of 8 patients also underwent an IAP. With the exception of 2 patients who showed right hemisphere dominance, all other patients showed left hemisphere dominance for language on the MEG recording. The IAP findings were consistent with MEG results in 7 patients. The eighth patient who, according to the MEG data, had probable right hemisphere dominance for language did not show clear hemispheric specialization for language on the IAP and suffered a transient global aphasia following a right temporal lobotomy. These results suggests that MEG-based language mapping can play an important role in presurgical clinical evaluation.

Neuropathological Findings in a Patient with Epilepsy and the Parry–Romberg Syndrome

Summary:  Purpose: The Parry–Romberg syndrome is an unusual disorder frequently associated with epilepsy. The origin of this disease, and the cause of epilepsy, are unknown. This study is the first reported case of the Parry–Romberg syndrome, with intractable temporal lobe epilepsy, in which detailed microanatomic analyses have been performed on resected brain tissue obtained after surgical intervention.

Perception and recall of faces and facial expressions following temporal lobectomy.

The perception of and memory for faces, with or without emotional content, were studied in 43 patients with temporal lobe epilepsy who had undergone unilateral resection of the hippocampus and the amygdala and in 43 healthy participants for comparison. Each participant performed four tasks from the Florida Affect Battery (Facial Discrimination, Affect Discrimination, Affect Naming, Affect Selection) and two memory tasks (in one case of a face and in the other of a facial expression). Findings indicated that, although patients with unilateral temporal lobectomy (right or left) showed no difficulty in discriminating faces, they were not as good at remembering faces. Also, patients who had had a left temporal lobectomy showed impairment in discriminating facial expressions, in the memory of a facial expression and/or in naming facial expressions.

Is a neutral expression also a neutral stimulus? A study with functional magnetic resonance.

Although neutral faces do not initially convey an explicit emotional message, it has been found that individuals tend to assign them an affective content. Moreover, previous research has shown that affective judgments are mediated by the task they have to perform. Using functional magnetic resonance imaging in 21 healthy participants, we focus this study on the cerebral activity patterns triggered by neutral and emotional faces in two different tasks (social or gender judgments). Results obtained, using conjunction analyses, indicated that viewing both emotional and neutral faces evokes activity in several similar brain areas indicating a common neural substrate. Moreover, neutral faces specifically elicit activation of cerebellum, frontal and temporal areas, while emotional faces involve the cuneus, anterior cingulated gyrus, medial orbitofrontal cortex, posterior superior temporal gyrus, precentral/postcentral gyrus and insula. The task selected was also found to influence brain activity, in that the social task recruited frontal areas while the gender task involved the posterior cingulated, inferior parietal lobule and middle temporal gyrus to a greater extent. Specifically, in the social task viewing neutral faces was associated with longer reaction times and increased activity of left dorsolateral frontal cortex compared with viewing facial expressions of emotions. In contrast, in the same task emotional expressions distinctively activated the left amygdale. The results are discussed taking into consideration the fact that, like other facial expressions, neutral expressions are usually assigned some emotional significance. However, neutral faces evoke a greater activation of circuits probably involved in more elaborate cognitive processing.

Effects of surgical treatment on intellectual performance and memory in a Spanish sample of drug-resistant partial onset-temporal lobe epilepsy patients

Knowledge of the effects of surgical treatment of epilepsy on mnesic functions has been steadily increasing in recent years. However, while some authors claim that this function remains seriously impaired after surgery, others argue that there is some recovery. In this study, we compare the pre- and post-operative results (one-year follow-up) of 55 patients (30 with right-temporal localization and 25 with left) suffering from drug-resistant partial-temporal epilepsy. Results of pre-surgical evaluation show that 42% of the patients had memory alterations of both verbal and visuo-spatial types, this group being made up of those patients that had been ill for longest (mean of 20 years). The remaining patients showed more specific deficits related to a particular type of information. Post-surgical results show that the general IQ increase was significant, even though no significant differences were found for general memory.Nevertheless, patients with right-temporal localization showed considerable improvement in verbal memory tasks (contralateral to the area operated on), while the performance of patients with left-temporal localization deteriorated slightly in these tasks (ipsilateral to the area operated on). In the visual memory tests no changes occurred in any of the groups.

A holistic analysis of relationships between executive function and memory in Parkinson's disease

Apart from motor symptoms, Parkinsons disease is characterized by executive and memory problems that have been observed from early stages of the disease. This study explores the possible relationships between these cognitive impairments in a group of 23 individuals with Parkinsons disease (PD) in comparison to a group of 18 healthy individuals. Compared with young individuals, normal aging is characterized by an increased association between executive function and episodic memory, especially with verbal material. We hypothesize that this association between verbal episodic memory and executive function may be weaker in PD as a consequence of the decline in these two cognitive abilities. To test this hypothesis, three categories of standardized tests were administered to both groups: (a) tests for executive function, (b) tests for visuospatial episodic memory, and (c) tests for verbal episodic memory. Performance outputs were analyzed using factor analysis, canonical regression, and structural equation modeling to obtain a holistic perspective of the linkage of these processes and to compare the differences between groups. In general, PD patients performed worse than controls in both executive function and episodic memory (with verbal and visuospatial material). Moreover, we found that relationships between executive function and visuospatial memory scores were high and quite similar in both groups. However, the relationship between verbal episodic memory and executive function was weaker in PD than in healthy individuals. These results suggest that a different brain mechanism could explain executive and verbal memory impairments in PD.

Discrimination and categorization of emotional facial expressions and faces in Parkinson's disease

Our objective was to compare the ability to discriminate and categorize emotional facial expressions (EFEs) and facial identity characteristics (age and/or gender) in a group of 53 individuals with Parkinsons disease (PD) and another group of 53 healthy subjects. On the one hand, by means of discrimination and identification tasks, we compared two stages in the visual recognition process that could be selectively affected in individuals with PD. On the other hand, facial expression versus gender and age comparison permits us to contrast whether the emotional or non-emotional content influences the configural perception of faces. In Experiment I, we did not find differences between groups, either with facial expression or age, in discrimination tasks. Conversely, in Experiment II, we found differences between the groups, but only in the EFE identification task. Taken together, our results indicate that configural perception of faces does not seem to be globally impaired in PD. However, this ability is selectively altered when the categorization of emotional faces is required. A deeper assessment of the PD group indicated that decline in facial expression categorization is more evident in a subgroup of patients with higher global impairment (motor and cognitive). Taken together, these results suggest that the problems found in facial expression recognition may be associated with the progressive neuronal loss in frontostriatal and mesolimbic circuits, which characterizes PD.

Protocolo de evaluación neuropsicológica en pacientes epilépticos

Resumen Desde hace un ano que se inicio la cirugia de la epilepsia en nuestro Hospital, todos los pacientes susceptibles de tratamiento quirurgico son evaluados antes y despues de la intervencion quirurgica desde el punto de vista neuropsicologico. La bateria utilizada cumple una serie de condiciones y evalua duerentes funciones: intelectuales, linguisticas, gnosicas, praxicas, mnesicas, lateralizacion, memoria… Se valoran tanto las funciones alteradas como las preservadas y se realiza un analisis conjunto de los datos neuropsicologicos, relacionando los resultados con las caracteristicas lesionales y quirurgicas.