Browsing by Author "Sousa, N"
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- Age effects on EEG correlates of the Wisconsin Card Sorting TestPublication . Dias, NS; Ferreira, D; Reis, J; Jacinto, LR; Fernandes, L; Pinho, F; Festa, J; Pereira, M; Afonso, N; Santos, NC; Cerqueira, JJ; Sousa, NBody and brain undergo several changes with aging. One of the domains in which these changes are more remarkable relates with cognitive performance. In the present work, electroencephalogram (EEG) markers (power spectral density and spectral coherence) of age-related cognitive decline were sought whilst the subjects performed the Wisconsin Card Sorting Test (WCST). Considering the expected age-related cognitive deficits, WCST was applied to young, mid-age and elderly participants, and the theta and alpha frequency bands were analyzed. From the results herein presented, higher theta and alpha power were found to be associated with a good performance in the WCST of younger subjects. Additionally, higher theta and alpha coherence were also associated with good performance and were shown to decline with age and a decrease in alpha peak frequency seems to be associated with aging. Additionally, inter-hemispheric long-range coherences and parietal theta power were identified as age-independent EEG correlates of cognitive performance. In summary, these data reveals age-dependent as well as age-independent EEG correlates of cognitive performance that contribute to the understanding of brain aging and related cognitive deficits.
- Assessing Cognitive Function in Older Adults Using a Videoconference ApproachPublication . Castanho, TC; Amorim, L; Moreira, PS; Mariz, J; Palha, JA; Sousa, N; Santos, NCBACKGROUND: The use of communication technologies is an emerging trend in healthcare and research. Despite efficient, reliable and accurate neuropsychological batteries to evaluate cognitive performance in-person, more diverse and less expensive and time consuming solutions are needed. Here we conducted a pilot study to determine the applicability of a videoconference (VC, Skype®) approach to assess cognitive function in older adults, using The Telephone Interview for Cognitive Status-Modified - Portuguese version (TICSM-PT). METHODS: After inclusion and exclusion criteria, 69 individuals (mean age=74.90±9.46years), selected from registries of local health centers and assisted-living facilities, were assessed on cognitive performance using videoconference, telephone and in-person approaches. FINDINGS: The videoconference administration method yielded comparable results to the traditional application. Correlation analyses showed high associations between the testing modalities: TICSM-PT VC and TICSM-PT telephone (r=0.885), TICSM-PT VC and MMSE face-to-face (r=0.801). Using the previously validated threshold for cognitive impairment on the TICSM-PT telephone, TICSM-PT VC administration presented a sensitivity of 87.8% and a specificity of 84.6%. INTERPRETATION: Findings indicate for the range of settings where videoconference approaches can be used, and for their applicability and acceptability, providing an alternative to current cognitive assessment methods. Continued validation studies and adaptation of neuropsychological instruments is warranted.
- Brain functional connectivity is altered in patients with Takotsubo SyndromePublication . Silva, AR; Magalhães, R; Arantes, C; Moreira, PS; Rodrigues, M; Marques, P; Marques, J; Sousa, N; Pereira, VHTakotsubo syndrome (TTS) is an acute, reversible cardiomyopathy. The central autonomic nervous system (ANS) is believed to play a role in this disease. The aim of the present study was to investigate the patterns of brain functional connectivity in a sample of patients who had experienced a previous episode of TTS. Brain functional connectivity, both at rest and in response to the stressful stimulus of topical cold stimulation, was explored using functional magnetic resonance imaging (fMRI), network-based statistics (NBS) and graph theory analysis (GTA) in a population consisting of eight patients with a previous episode of TTS and eight sex- and age-matched controls. At rest, a network characterized by increased connectivity in the TTS group compared to controls and comprising elements of the central ANS was identified. GTA revealed increased local efficiency, clustering and strength in regions of the bilateral hippocampus in subjects with a previous episode of TTS. When stressed by local exposure to cold, the TTS group differed significantly from both a pre-stress baseline interval and from the control group, showing increased connectivity in a network that included the left amygdala and the right insula. Based on the results, patients with TTS display a reorganization of cortical and subcortical networks, including areas associated with the emotional response and autonomic regulation. The findings tend to support the hypothesis that a deregulation of autonomic control at the central level plays a significant role in this syndrome.
- Brain structure across the lifespan: the influence of stress and moodPublication . Soares, JM; Marques, P; Magalhães, R; Santos, NC; Sousa, NNormal brain aging is an inevitable and heterogeneous process characterized by a selective pattern of structural changes. Such heterogeneity arises as a consequence of cumulative effects over the lifespan, including stress and mood effects, which drive different micro- and macro-structural alterations in the brain. Investigating these differences in healthy age-related changes is a major challenge for the comprehension of the cognitive status. Herein we addressed the impact of normal aging, stress, mood, and their interplay in the brain gray and white matter (WM) structure. We showed the critical impact of age in the WM volume and how stress and mood influence brain volumetry across the lifespan. Moreover, we found a more profound effect of the interaction of aging/stress/mood on structures located in the left hemisphere. These findings help to clarify some divergent results associated with the aging decline and to enlighten the association between abnormal volumetric alterations and several states that may lead to psychiatric disorders.
- Cortical maturation in fetuses referred for ‘isolated’ mild ventriculomegaly: a longitudinal ultrasound assessmentPublication . Miguelote, RF; Vides, B; Santos, RF; Palha, JA; Matias, A; Sousa, NOBJECTIVES: To compare cortical maturation between fetuses with isolated mild ventriculomegaly (IMV) and healthy fetuses, and to explore its potential prognostic value in IMV. METHODS: This prospective study quantified cortical maturation by ultrasound in 24 fetuses with IMV and 46 healthy fetuses. Depth and grading the developmental pattern of the parieto-occipital fissure (POF), calcarine fissure (CF) and sylvian fissure, and grading the Sylvian fissure operculization at 23-25, 27-28 and 31-32 weeks gestation were determined. RESULTS: At 23-25 and 27-28 gestational weeks, POF and CF mean depths were statistically lower in the IMV group. The POF and CF depth distribution had a normal distribution in the control group but displayed a bimodal distribution in the IMV group. IMV with progression of ventricular dilatation showed mean depth of CF lower than IMV in which ventriculomegaly regressed or remained stable. The sensitivity, specificity, positive predictive value and negative predictive value of a CF depth below the fifth percentile to predict progression of ventricular dilatation were, at 28 weeks, 100%, 88%, 67% and 100%, respectively. CONCLUSIONS: Cortical fissure assessment by ultrasound allowed the differentiation of a subgroup of IMV fetuses with a higher risk of progression of ventricular dilatation.
- Efeitos da Exposição Pré-natal à Dexametasona na Mucosa GástricaPublication . Leão, P; Oliveira, M; Botelho, C; Mariz, J; Roque, S; Correia-Neves, M; Sousa, N
- Effect of triamcinolone intravitreal injection in previously vitrectomized eyesPublication . Sousa, N; Sousa, K; Mendonça, L; Gentil, R; Calvão-Santos, G; Leite, R; Mendes, J
- Effector memory CD4(+) T cells are associated with cognitive performance in a senior populationPublication . Serre-Miranda, C; Roque, S; Santos, NC; Portugal-Nunes, C; Costa, P; Palha, JA; Sousa, N; Correia-Neves, MOBJECTIVE: Immunosenescence and cognitive decline are common markers of the aging process. Taking into consideration the heterogeneity observed in aging processes and the recently described link between lymphocytes and cognition, we herein explored the possibility of an association between alterations in lymphocytic populations and cognitive performance. METHODS: In a cohort of cognitively healthy adults (n = 114), previously characterized by diverse neurocognitive/psychological performance patterns, detailed peripheral blood immunophenotyping of both the innate and adaptive immune systems was performed by flow cytometry. RESULTS: Better cognitive performance was associated with lower numbers of effector memory CD4(+) T cells and higher numbers of naive CD8(+) T cells and B cells. Furthermore, effector memory CD4(+) T cells were found to be predictors of general and executive function and memory, even when factors known to influence cognitive performance in older individuals (e.g., age, sex, education, and mood) were taken into account. CONCLUSIONS: This is the first study in humans associating specific phenotypes of the immune system with distinct cognitive performance in healthy aging.
- Plasticity of resting state brain networks in recovery from stressPublication . Soares, JM; Sampaio, A; Marques, P; Ferreira, LM; Santos, NC; Marques, F; Palha, JA; Cerqueira, JJ; Sousa, NChronic stress has been widely reported to have deleterious impact in multiple biological systems. Specifically, structural and functional remodeling of several brain regions following prolonged stress exposure have been described; importantly, some of these changes are eventually reversible. Recently, we showed the impact of stress on resting state networks (RSNs), but nothing is known about the plasticity of RSNs after recovery from stress. Herein, we examined the "plasticity" of RSNs, both at functional and structural levels, by comparing the same individuals before and after recovery from the exposure to chronic stress; results were also contrasted with a control group. Here we show that the stressed individuals after recovery displayed a decreased resting functional connectivity in the default mode network (DMN), ventral attention network (VAN), and sensorimotor network (SMN) when compared to themselves immediately after stress; however, this functional plastic recovery was only partial as when compared with the control group, as there were still areas of increased connectivity in dorsal attention network (DAN), SMN and primary visual network (VN) in participants recovered from stress. Data also shows that participants after recovery from stress displayed increased deactivations in DMN, SMN, and auditory network (AN), to levels similar to those of controls, showing a normalization of the deactivation pattern in RSNs after recovery from stress. In contrast, structural changes (volumetry) of the brain areas involving these networks are absent after the recovery period. These results reveal plastic phenomena in specific RSNs and a functional remodeling of the activation-deactivation pattern following recovery from chronic-stress, which is not accompanied by significant structural plasticity.
- Prenatal Exposure Dexamethasone Alters the Cytokine Profile: Implications for Peptic DiseasePublication . Leão, P; Oliveira, M; Botelho, CM; Mariz, J; Lamas, N; Sousa, N
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