Categoría: Papers con abstracts

BACKGROUND: Based on the higher frequency of paroxysmal atrial fibrillation during night and early morning hours, we sought to analyze the association between newly diagnosed atrial fibrillation and wake-up ischemic cerebrovascular events.METHODS: We prospectively assessed every acute ischemic stroke and TIA patient admitted to our hospital between 2008 and 2011. We used a forward step-by-step multiple logistic regression analysis to assess the relationship between newly diagnosed atrial fibrillation and wake-up ischemic stroke or TIA, after adjusting for significant covariates.RESULTS: The study population comprised 356 patients, 274 (77.0%) with a diagnosis of acute ischemic stroke and 82 (23.0%) with TIA. A total of 41 (11.5%) of these events occurred during night sleep. A newly diagnosed atrial fibrillation was detected in 27 patients of 272 without known atrial fibrillation (9.9%). We found an independent association between newly diagnosed atrial fibrillation and wake-up ischemic stroke and TIA (odds ratio 3.6, 95% confidence interval 1.2-7.7, p = 0.019).CONCLUSIONS: The odds of detecting a newly diagnosed atrial fibrillation were 3-fold higher among wake-up cerebrovascular events than among non-wake-up events. The significance of this independent association between newly diagnosed atrial fibrillation and wake-up ischemic stroke and TIA and the role of other comorbidities should be investigated in future studies.

Background: Interoception refers to the conscious perception of body signals. Mindfulness is ameditation that encourages individuals to focus on their internal experiences such as bodilysensations, thoughts, and emotions. In this study we selected a behavioral measure ofinteroceptive sensitivity (heartbeat detection task, HBD) to compare the effect of meditationpractice on interoceptive sensitivity among long term practitioners (LTP), short term meditators(STM, subjects that completed a Mindfulness-Based Stress Reduction (MBSR) program) andcontrols (non-meditators). All participants were examined with a battery of different tasksincluding mood state, executive function and social cognition tests (emotion recognition,empathy and theory of mind).Findings: Compared to controls, both meditators’ groups showed lower levels of anxiety anddepression, but no improvement in executive function or social cognition performance wasobserved (except for lower scores compared to controls only in the personal distress dimensionof empathy). More importantly, meditators´ performance did not differ from that ofnonmeditators regarding cardiac interoceptive sensitivity.Conclusion: Results suggest no influence of meditation practice in cardiac interoception and inmost related social cognition measures. These negative results could be partially due to the factthat awareness of heartbeat sensations is not emphasized during mindfulness/vipassanameditation and may not be the best index of the awareness supported by the practice ofmeditation.

BACKGROUND: The dimensional approach to autism spectrum disorder (ASD) considers ASD as the extreme of a dimension traversing through the entire population. We explored the potential utility of electroencephalography (EEG) functional connectivity as a biomarker. We hypothesized that individual differences in autistic traits of typical subjects would involve a long-range connectivity diminution within the delta band. METHODS: Resting-state EEG functional connectivity was measured for 74 neurotypical subjects. All participants also provided a questionnaire (Social Responsiveness Scale, SRS) that was completed by an informant who knows the participant in social settings. We conducted multivariate regression between the SRS score and functional connectivity in all EEG frequency bands. We explored modulations of network graph metrics characterizing the optimality of a network using the SRS score. RESULTS: Our results show a decay in functional connectivity mainly within the delta and theta bands (the lower part of the EEG spectrum) associated with an increasing number of autistic traits. When inspecting the impact of autistic traits on the global organization of the functional network, we found that the optimal properties of the network are inversely related to the number of autistic traits, suggesting that the autistic dimension, throughout the entire population, modulates the efficiency of functional brain networks. CONCLUSIONS: EEG functional connectivity at low frequencies and its associated network properties may be associated with some autistic traits in the general population.

Cockayne syndrome (CS) is an autosomal recessive disease associated with premature aging, progressive multiorgan degeneration, and nervous system abnormalities including cerebral and cerebellar atrophy, brain calcifications, and white matter abnormalities. Although several clinical descriptions of CS patients have reported developmental delay and cognitive impairment with relative preservation of social skills, no previous studies have carried out a comprehensive neuropsychological and social cognition assessment. Furthermore, no previous research in individuals with CS has examined the relationship between brain atrophy and performance on neuropsychological and social cognition tests. This study describes the case of an atypical late-onset type III CS patient who exceeds the mean life expectancy of individuals with this pathology. The patient and a group of healthy controls underwent a comprehensive assessment that included multiple neuropsychological and social cognition (emotion recognition, theory of mind, and empathy) tasks. In addition, we compared the pattern of atrophy in the patient to controls and to its concordance with ERCC8 gene expression in a healthy brain. The results showed memory, language, and executive deficits that contrast with the relative preservation of social cognition skills. The cognitive profile of the patient was consistent with his pattern of global cerebral and cerebellar loss of gray matter volume (frontal structures, bilateral cerebellum, basal ganglia, temporal lobe, and occipito-temporal/occipito-parietal regions), which in turn was anatomically consistent with the ERCC8gene expression level in a healthy donor’s brain. The study of exceptional cases, such as the one described here, is fundamental to elucidating the processes that affect the brain in premature aging diseases, and such studies provide an important source of information for understanding the problems associated with normal and pathological aging.

Converging neuroscientific evidence suggests the existence of close links between language and sensorimotor cognition. Accordingly, during the comprehension of meaningful actions, our brain would recruit semantic-related operations similar to those associated with the processing of language information. Consistent with this view, electrophysiological findings show that the N400 component, traditionally linked to the semantic processing of linguistic material, can also be elicited by action-related material. This review outlines recent data from N400 studies that examine the understanding of action events. We focus on three specific domains, including everyday action comprehension, co-speech gesture integration, and the semantics involved in motor planning and execution. Based on the reviewed findings, we suggest that both negativities (the N400 and the action-N400) reflect a common neurocognitive mechanism involved in the construction of meaning through the expectancies created by previous experiences and current contextual information. To shed light on how this process is instantiated in the brain, a testable contextual fronto-temporo-parietal model is proposed.

Even though cerebellar activation has been described during theory of mind (ToM) tasks in neuroimaging studies, no previous studies have investigated ToM in a group of patients with cerebellar strokes. In the present study, we assessed 11 patients with cerebellar infarction on a variety of executive tests and with the Faux Pas test of ToM. Even if cerebellar patients showed significant deficits on executive tasks relative to a control group, no significant differences were found between the groups on the Faux Pas test. This is the first group study to demonstrate that focal cerebellar lesions do not affect ToM.

Psychiatric Conditions That Can Mimic Early Behavioral Variant Frontotemporal Dementia: The Importance of the New Diagnostic Criteria. Autores Manes F, Báez S, Couto JB, Herrera E, Trujillo-Orrego N, Cardona JF, Ibanez A.  Año 2012 Journal  Manes F, Báez S, Couto JB, Herrera E, Trujillo-Orrego N, Cardona JF, Ibanez A.  Volumen 14(5): 450-452 Abstract   Otra información  La publicación trata sobre la importancia de los nuevos criterios en … Leer más

The significance of social situations is commonly context-embedded. Although the role of context has been extensively studied in basic sensory processing or simple stimulus-response settings, its relevance for social cognition is unknown. We propose the social context network model (SCNM), a fronto-insular-temporal network responsible for processing social contextual effects. The SCNM may 1) update the context and use it to make predictions, 2) coordinate internal and external milieus, and 3) consolidate context-target associative learning. We suggest the behavioral variant of frontotemporal dementia (bvFTD) as a specific disorder in which the reported deficits in social cognition (e.g., facial recognition, empathy, decision-making, figurative language, theory of mind) can be described as context impairments due to deficits in the SCNM. Disruption of orbitofrontal-amygdala circuit, as well as the frontal, temporal, and insular atrophy in bVFTD, suggests a relationship between context-sensitive social cognition and SCNM. In considering context as an intrinsic part of social cognition, we highlight the need for a situated cognition approach in social cognition research as opposed to an abstract, universal, and decontextualized approach. The assessment of context-dependent social cognition paradigms, the SCNM, and their possible application to neuropsychiatric disorders may provide new insight into bvFTD and other related frontal disorders.

Letter by Sposato and Saposnik regarding article, «Socioeconomic status and stroke: an updated review». Autores Sposato L, Saposnik G.  Año 2012 Journal  Sposato L, Saposnik G.  Volumen 43(8): 77 Abstract   Otra información    

This study examines performance of schizophrenia patients, unaffected relatives and controls in social cognition, cognitive and psychiatric scales looking for possible markers of vulnerability in schizophrenia. Performance of schizophrenia patients from multiplex families, first-degree relatives, and matched controls was compared and, subsequently, discriminant analysis method was used for identifying the best predictors for group membership. By using Multigroup Discriminant Analyses on the three groups, the best predictors were PANSS, Premorbid Adjustment Scale, Faux Pas test, and a face/emotion categorizing task. This model obtained 82% correct global classification, suggesting that the combination of psychiatric scales and neuropsychological/social cognition tasks are the best approach for characterizing this disease. Although preliminary, our results suggest that social cognition tasks are robust markers of schizophrenia family impairments, and that combining clinical, social and neuropsychological measures is the best approach to asses patients and relatives vulnerability.