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Dive into the research topics where Sandra Freitas is active.

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Featured researches published by Sandra Freitas.


Alzheimer Disease & Associated Disorders | 2013

Montreal cognitive assessment: validation study for mild cognitive impairment and Alzheimer disease.

Sandra Freitas; Mário R. Simões; Lara Alves; Isabel Santana

The Montreal Cognitive Assessment (MoCA) was recently proposed as a cognitive screening test for milder forms of cognitive impairment, having surpassed the well-known limitations of the Mini-Mental State Examination (MMSE). This study aims to validate the MoCA for screening Mild Cognitive Impairment (MCI) and Alzheimer disease (AD) through an analysis of diagnostic accuracy and the proposal of cut-offs. Patients were classified into 2 clinical groups according to standard criteria: MCI (n=90) and AD (n=90). The 2 control groups (C-MCI: n=90; C-AD: n=90) consisted of cognitively healthy community dwellers selected to match patients in sex, age, and education. The MoCA showed consistently superior psychometric properties compared with the MMSE, and higher diagnostic accuracy to discriminate between MCI (area under the curve=0.856; 95% confidence interval, 0.796-0.904) and AD patients (area under the curve=0.980; 95% confidence interval, 0.947-0.995). At an optimal cut-off of below 22 for MCI and below 17 for AD, the MoCA achieved significantly superior values in comparison with MMSE for sensitivity, specificity, positive predictive value, negative predictive value, and classification accuracy. Furthermore, the MoCA revealed higher sensitivity to cognitive decline in longitudinal monitoring. This study provides robust evidence that the MoCA is a better cognitive tool than the widely used MMSE for the screening and monitoring of MCI and AD in clinical settings.


Journal of Clinical and Experimental Neuropsychology | 2011

Montreal Cognitive Assessment (MoCA): Normative study for the Portuguese population

Sandra Freitas; Mário R. Simões; Lara Alves; Isabel Santana

The Montreal Cognitive Assessment (MoCA) is a brief cognitive screening instrument with good psychometric features and an excellent sensitivity in the early detection of mild cognitive decline. The MoCA was applied to a community-based sample of cognitively healthy adults (n = 650), stratified according to sociodemographic variables (age, gender, educational level, geographic region, geographic localization, and residence area), with a distribution similar to that observed in the Portuguese population. The normative data were determined according to age and education as these were the sociodemographic variables that most significantly contributed to the prediction of the MoCA scores, explaining 49% of their variance.


Journal of The International Neuropsychological Society | 2012

Montreal Cognitive Assessment (MoCA): Validation Study for Vascular Dementia

Sandra Freitas; Mário R. Simões; Lara Alves; Margarida Vicente; Isabel Santana

The Montreal Cognitive Assessment (MoCA) is a brief instrument developed for the screening of milder forms of cognitive impairment, having surpassed the well-known limitations of the MMSE. The aim of the present study was to validate the MoCA as well as its short version, which was proposed by the NINDS-CSN VCI Harmonization Standards for screening Vascular Dementia (VaD) patients. The results, based on a homogeneous sample of 34 VaD patients, indicate that the MoCA is a psychometrically valid and reliable instrument for cognitive screening in VaD patients, showing excellent discriminant validity. Both the full and short versions of the MoCA had excellent diagnostic accuracy in discriminating VaD patients, exhibiting an area under curve (AUC) higher than the MMSE [AUC(MoCA full version) = .950; 95% IC = .868-.988; AUC(MoCA short version) = .936; 95% IC = .849-.981; AUC(MMSE) = .860; 95% IC = .754-.932]. With a cutoff below 17 on the MoCA full version and 8 on the short version, the results for sensitivity, specificity, positive and negative predictive values, and classification accuracy were superior compared to the MMSE. In conclusion, both versions of the MoCA are valid, reliable, sensitive and accurate screening instruments for VaD patients.


Journal of Geriatric Psychiatry and Neurology | 2012

Montreal Cognitive Assessment (MoCA): Validation study for Frontotemporal Dementia:

Sandra Freitas; Mário R. Simões; Lara Alves; Diana Duro; Isabel Santana

The Montreal Cognitive Assessment (MoCA) is a brief instrument developed for the screening of milder forms of cognitive impairment, having surpassed the well-known limitations of the Mini-Mental State Examination (MMSE). The aim of the present study was to validate the MoCA as a cognitive screening test for behavioral-variant frontotemporal dementia (bv-FTD) by examining its psychometric properties and diagnostic accuracy. Three matched subgroups of participants were considered: bv-FTD (n = 50), Alzheimer disease (n = 50), and a control group of healthy adults (n = 50). Compared with the MMSE, the MoCA demonstrated consistently superior psychometric properties and discriminant capacity, providing comprehensive information about the patients’ cognitive profiles. The diagnostic accuracy of MoCA for bv-FTD was extremely high (area under the curve AUC [MoCA] = 0.934, 95% confidence interval [CI] = 0.866-.974; AUC [MMSE] = 0.772, 95% CI = 0.677-0.850). With a cutoff below 17 points, the MoCA results for sensitivity, specificity, positive predictive value, negative predictive value, and classification accuracy were significantly superior to those of the MMSE. The MoCA is a sensitive and accurate instrument for screening the patients with bv-FTD and represents a better option than the MMSE.


Clinical Neuropsychologist | 2014

Psychometric Properties of the Montreal Cognitive Assessment (MoCA): An Analysis Using the Rasch Model

Sandra Freitas; Gerardo Prieto; Mário R. Simões; Isabel Santana

In the present study we analyzed the psychometric characteristics of the MoCA (Portuguese version) using the Rasch model for dichotomous items. The total sample comprised of 897 participants distributed between two main subgroups: (I) healthy group that was comprised of 650 cognitively healthy community dwellers and (II) clinical group that was comprised of 90 patients with Mild Cognitive Impairment, 90 patients with Alzheimer’s disease, 33 patients with frontotemporal dementia, and 34 patients with vascular dementia recruited at a reference dementia clinic. All patients were investigated through a comprehensive neuropsychological assessment, laboratory tests essential to exclude a reversible form of dementia, imaging studies (CT or MRI and SPECT or FDG-PET), Apolipoprotein E allele genotyping and CSF biomarker (Aβ42,Tau, and P-tau) analyses. The clinical diagnosis was established through the consensus of a multidisciplinary team, based on international criteria. The results demonstrated an overall good fit of both items and the person’s values, a high variability on cognitive performance level, and a good quality of the measurements. The MoCA scores also demonstrated adequate discriminant validity, with high diagnostic value. DIF analyses indicated the generalized validity of the MoCA scores. In conclusion, the results of this study show the overall psychometric adequacy of the MoCA and verify the discriminant and generalized validity of the obtained results.


Journal of Geriatric Psychiatry and Neurology | 2013

Premorbid IQ Influence on Screening Tests’ Scores in Healthy Patients and Patients With Cognitive Impairment

Lara Alves; Mário R. Simões; Cristina Martins; Sandra Freitas; Isabel Santana

Cognitive screening tests are well-established tools for detecting cognitive impairment, but concerns regarding the influence of premorbid intelligence on patient’s performance and cognitive status classification remain. Risk of inaccurate assessment especially affects the elders with high or low premorbid intelligence (who are more likely to be misclassified). The present study examines the influence of premorbid intelligence assessed by the TeLPI (an irregular words reading test) on 2 cognitive screening tests, the Mini-Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA), in healthy participants and patients with cognitive impairments (mild cognitive impairment and Alzheimer disease). Results show that premorbid IQ influences the MMSE and the MoCA scores in both the groups, predicting variance from 8.4% to 33.2%, according to test and group analyzed. Hence, we propose that whenever the MMSE or the MoCA is used, premorbid IQ evaluation should also be considered to ensure correct interpretation and classification.


Multiple Sclerosis Journal | 2017

Impairment of social cognition in multiple sclerosis: Amygdala atrophy is the main predictor

Sónia Batista; Otília C. d’Almeida; Ana Afonso; Sandra Freitas; Carmo Macário; L Sousa; Miguel Castelo-Branco; Isabel Santana; Luís Cunha

Background: Patients with multiple sclerosis (MS) frequently reveal social behavior disturbance. Nevertheless, little is known regarding the impact of MS on social cognition, particularly theory of mind (ToM), and its neural basis. Objectives: To explore how ToM is affected in MS and its neural correlates. Methods: Enrolled 60 consecutive MS patients and 60 healthy controls (HC) matched on age, sex, and education. Participants underwent ToM testing (Eyes Test, Videos Test) and 3 T brain magnetic resonance imaging (MRI). Using Freesurfer software, cortical and subcortical gray matter (GM) volumes were calculated. Results: MS patients performed worse on Eyes Test (58.7% ± 13.8% vs 81.9% ± 10.4%, p < 0.001) and Videos Test (75.3% ± 9.3% vs 88.1% ± 7.1%, p < 0.001). Eyes Test performance in MS was positively correlated with the volume of subcortical structures (amygdala, putamen) and cortical regions (entorhinal cortex, fusiform gyrus, superior temporal gyrus, superior parietal gyrus, supramarginal gyrus, medial orbitofrontal cortex, anterior and posterior cingulate gyrus). In regression analysis, amygdala volume was the single predictor of performance (R2 change = 0.064, p = 0.031), and a mediation analysis indicated that it contributes for the differences observed between MS and HC. Conclusion: Patients with MS have impairment on social cognition. Amygdala atrophy was the main predictor probably due to its central position within the “social brain” network.


Applied Neuropsychology | 2015

The Relevance of Sociodemographic and Health Variables on MMSE Normative Data

Sandra Freitas; Mário R. Simões; Lara Alves; Isabel Santana

The Mini Mental State Examination (MMSE) is the most broadly used cognitive screening instrument in clinical and research contexts. The MMSE was administered to a community-based sample of cognitively healthy adults (n = 850), stratified according to several sociodemographic variables, with a distribution similar to that observed in the Portuguese population. This study aimed to analyze the influence of sociodemographic (age, gender, education level, marital and employment status, geographic region, geographic localization, and residence area) and health variables (subjective memory complaints of the participant and evaluated by the informant, depressive symptoms, and family history of dementia) on the participants’ performance on the MMSE and to establish normative data for the Portuguese population. Education level and age significantly contributed to the prediction of the MMSE scores and explained 26% of its variance. Regarding health variables, only the subjective memory complaints of the participant showed a small contribution (4%) to the variance of the MMSE scores. According to these results, age and education were considered in the development of the normative data of the MMSE for the Portuguese population.


Archives of Clinical Neuropsychology | 2013

The Clock Drawing Test: Portuguese norms, by age and education, for three different scoring systems.

Isabel Santana; Diana Duro; Sandra Freitas; Lara Alves; Mário R. Simões

The Clock Drawing Test has been systematically used to assess visuospatial deficits related to the parietal lobes, but we now acknowledge its much more complex relation with other cognitive abilities. Despite its common use in clinical and investigational practices, no study has developed normative data for the Portuguese population. We present the distribution of clock drawing scores using three scoring systems in a representative community sample of cognitively healthy subjects. We found that the systems were well correlated with each other and with cognitive screening tests widely used and had good psychometric properties. Normative data for the three scoring systems were developed considering age and education. These results allow a more rigorous interpretation of the test performance in clinical context and are especially relevant for epidemiological research.


Applied Neuropsychology | 2018

The Montreal Cognitive Assessment (MoCA) as a screening test for cognitive dysfunction in multiple sclerosis

Sandra Freitas; S. Batista; Ana Cristina Afonso; Mário R. Simões; L Sousa; Luís Cunha; Isabel Santana

ABSTRACT This study investigates the utility of the Portuguese version of Montreal Cognitive Assessment (MoCA) as a screening-method for identifying cognitive dysfunction (CD) in multiple sclerosis (MS). The 118 participants with comprehensive neuropsychological assessment were divided into two subgroups: (I) MS group (n = 59) and (II) control group (n = 59). The MS patients were classified as cognitively intact (n = 26) or impaired (n = 33, 56%). The results indicated that the MoCA is a psychometrically valid instrument in assessment of MS patients. The Multiple Linear Regression analyses highlighted the significant influence of Modified Fatigue Impact Scale and Irregular Word Reading Test on MoCA performance. The MoCA total score showed a good discriminative capacity between cognitively impaired and cognitively intact subjects. In addition, there were significant differences in MoCA cognitive domain scores between groups. The MoCA total score cut-off point for identifying CD in MS patients was a score below 26 points (AUC = 0.837, CI = 0.736–0.937). A proposed EM-MoCA-Subscore for identifying the MS-related cognitive impairment (max. score = 19 points, cut-off <17 points, AUC = 0.871, CI = 0.784–0.958), can reduce administration time for cognitive screening in clinical settings. The MoCA is a useful and sensitive instrument to identify the MS-related cognitive impairment.

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L Sousa

University of Coimbra

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