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Browsing by Author "Guerreiro, Manuela"

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  • O cérebro analfabeto : A questão da demência
    Publication . Guerreiro, Manuela; Castro-Caldas, Alexandre; Reis, Alexandra Isabel Dias; Garcia, Carlos
    O baixo nível cultural e educacional tem sido refe - rido na literatura, como um factor de risco para a doença de Alzheimer. Em Portugal, a prevalência de analfabetismo é muito alta, especialmente na faixa etária em que esta demência surge. O nosso estudo tem como objectivo estabelecer a relação entre estes dois factores, segundo a hipótese de que, se a cognição nos sujeitos de escolaridade baixa dificulta, associações semânticas (quando comparadas com as simbólicas, de nível superior) e se a doença de Alzheimer afecta, principalmente, os mecanismos semânticos e da memória, o padrão da alteração cognitiva deverá ser diferente, se compararmos duas populações de diferentes níveis educacionais. Os resultados obtidos por 64 sujeitos (46 com doença de Alzheimer e 18 controlos) e por 59 analfabetos (26 com doença de Alzheimer e 33 controlos), numa bateria de testes para demência confirma esta hipótese. Pode ser concluído que a cultura contribui para o desenvolvimento de mecanismos de associação, que estão baseados em diferentes estruturas e que podem ser considerados mais «primitivos». A doença produz efeitos, principalmente, em áreas responsáveis pelos mecanismos «primitivos» e poupa os mais sofisticados, pelo menos no inicio da evolução da doença. Palavras
    1996Journal article Open access Show more
  • Cognitive deficits in middle-aged and older adults with bipolar disorder and cognitive complaints: Comparison with mild cognitive impairment
    Publication . Silva, Dina Lúcia Gomes da; Santana, Isabel; Couto, Frederico Simões do; Maroco, João; Guerreiro, Manuela; Mendonça, Alexandre de
    Objective Cognitive impairment has been reported in elderly bipolar disorder (BD) patients, however, few studies have evaluated middle-aged and older BD patients using standardized cognitive assessments and none (to our knowledge) analysed middle-aged and older BD patients with recent cognitive complaints. The main objective of this study is to characterize the cognitive deficits of middle-aged and older patients with BD and compare them with the common agerelated cognitive deficits observed in Mild Cognitive Impairment (MCI). Methods For this retrospective study, a systematic search for all cases of BD patients submitted to a neuropsychological assessment from 1999–2007, at participant institutions, was performed, and cases were matched (1:2) by gender and age to a sample of MCI subjects. Results A total sample of 135 patients, 45 patients with the diagnosis of BD, clinically stable, mean age of 63.8 8.8 years, and 90 patients with the diagnosis of MCI, mean age of 64.2 8.4 years, was studied. Patients with MCI were more impaired in verbal memory, whereas BD patients showed more deficits in attention, motor initiative, calculation and verbal abstraction. Interestingly, discriminant analysis classified about half of the BD group as belonging to the MCI group. This BD subgroup showed deficits in episodic memory similar to MCI patients. Conclusions Patients with BD and patients with MCI have distinct profiles of cognitive impairment. A subgroup of BD patients with recent cognitive complaints may actually suffer from concomitant incipient MCI, and this finding may have diagnostic and therapeutical implications.
    2009Journal article Restricted access Show more
  • Comparison of four verbal memory tests for the diagnosis and predictive value of mild cognitive impairment
    Publication . Silva, Dina Lúcia Gomes da; Guerreiro, Manuela; Maroco, João; Santana, Isabel; Rodrigues, Ana; Marques, José Bravo; Mendonça, Alexandre de
    Background: Mild cognitive impairment (MCI) is considered to be an early stage of a neurodegenerative disorder, particularly Alzheimer’s disease, and the clinical diagnosis requires the objective demonstration of cognitive deficits. The aim of the present study was to evaluate the predictive value of MCI for the conversion to dementia when using four different verbal memory tests (Logical Memory, LM; California Verbal Learning Test, CVLT; Verbal Paired-Associate Learning, VPAL; and Digit Span, DS) in the MCI criteria. Methods: Participants were consecutive patients with subjective cognitive complaints who performed a comprehensive neuropsychological evaluation and were not demented, observed in a memory clinic setting. Results: At baseline, 272 non-demented patients reporting subjective cognitive complaints were included. During the follow-up time (3.0 +- 1.9 years), 58 patients converted to dementia and 214 did not. Statistically significant differences between the converters and non-converters were present in LM, VPAL, and CVLT. A multivariate Cox regression analysis combining the four memory tests revealed that only the CVLT test remained significant as a predictor of conversion to dementia. Non-demented patients with cognitive complaints diagnosed as having MCI according to abnormal ( < 1.5 SD) learning in the CVLT test had a 3.61 higher risk of becoming demented during the follow-up. Conclusion: The verbal memory assessment using the CVLT should be preferred in the diagnostic criteria of MCI for a more accurate prediction of conversion to dementia.
    2012Journal article Open access Show more
  • Data mining methods in the prediction of dementia: A real-data comparison of the accuracy, sensitivity and specificity of linear discriminant analysis, logistic regression, neural networks, support vector machines, classification trees and random forests
    Publication . Maroco, João Lúcia Gomes da; Silva, Dina Lúcia Gomes da; Rodrigues, Ana; Guerreiro, Manuela; Santana, Isabel; Mendonça, Alexandre de
    Background: Dementia and cognitive impairment associated with aging are a major medical and social concern. Neuropsychological testing is a key element in the diagnostic procedures of Mild Cognitive Impairment (MCI), but has presently a limited value in the prediction of progression to dementia. We advance the hypothesis that newer statistical classification methods derived from data mining and machine learning methods like Neural Networks, Support Vector Machines and Random Forests can improve accuracy, sensitivity and specificity of predictions obtained from neuropsychological testing. Seven non parametric classifiers derived from data mining methods (Multilayer Perceptrons Neural Networks, Radial Basis Function Neural Networks, Support Vector Machines, CART, CHAID and QUEST Classification Trees and Random Forests) were compared to three traditional classifiers (Linear Discriminant Analysis, Quadratic Discriminant Analysis and Logistic Regression) in terms of overall classification accuracy, specificity, sensitivity, Area under the ROC curve and Press’Q. Model predictors were 10 neuropsychological tests currently used in the diagnosis of dementia. Statistical distributions of classification parameters obtained from a 5-fold cross-validation were compared using the Friedman’s nonparametric test. Results: Press’ Q test showed that all classifiers performed better than chance alone (p < 0.05). Support Vector Machines showed the larger overall classification accuracy (Median (Me) = 0.76) an area under the ROC (Me = 0.90). However this method showed high specificity (Me = 1.0) but low sensitivity (Me = 0.3). Random Forest ranked second in overall accuracy (Me = 0.73) with high area under the ROC (Me = 0.73) specificity (Me = 0.73) and sensitivity (Me = 0.64). Linear Discriminant Analysis also showed acceptable overall accuracy (Me = 0.66), with acceptable area under the ROC (Me = 0.72) specificity (Me = 0.66) and sensitivity (Me = 0.64). The remaining classifiers showed overall classification accuracy above a median value of 0.63, but for most sensitivity was around or even lower than a median value of 0.5. Conclusions: When taking into account sensitivity, specificity and overall classification accuracy Random Forests and Linear Discriminant analysis rank first among all the classifiers tested in prediction of dementia using several neuropsychological tests. These methods may be used to improve accuracy, sensitivity and specificity of Dementia predictions from neuropsychological testing.
    2011Journal article Open access Show more
  • Delay discounting in mild cognitive impairment
    Publication . Coelho, Sara; Guerreiro, Manuela; Chester, Catarina Carapeto da Silva; Silva, Dina Lúcia Gomes da; Maroco, João; Paglieri, Fabio; Mendonça, Alexandre de
    Introduction : Patients with mild cognitive impairme nt (MCI) may make suboptimal decisions particularly in complex situations, and thi s could be due to temporal discounting, the tendency to prefer immediate rewards over delayed but larger rewards. The present study proposes to evaluate intertemporal prefere nces in MCI patients as compared to healthy controls. Method : Fifty-five patients with MCI and 57 h ealthy controls underwent neuropsy- chological evaluation and a delay discounting questionnaire, which evaluates three para- meters: hyperbolic discounting ( k ), the percentage of choices for delayed and later rewards (%LL), and response consistency (Acc). Results : No significant differences were found in the delay discounting questionnaire between MC I patients and controls for the three reward sizes considered, small, medium, and large, using both k and %LL parameters. There were also no differences in the response consistency, Acc, between the two groups. Conclusions : Patients with MCI perform similarly to healthy controls in a delay discounting task. Memory deficits do not notably affect intertemporal preferences.
    2016Journal article Restricted access Show more
  • Delinquência juvenil no feminino : Um estudo comparativo de raparigas institucionalizadas
    Publication . Pechorro, Pedro Fernandes dos Santos; Gama, Ana Paula; Guerreiro, Manuela; Maroco, João; Gonçalves, Rui Abrunhosa
    A presente investigação teve como objectivo analisar o papel desempenhado na delinquência juvenil feminina pelos constructos de traços psicopáticos, problemas de comportamento, comportamentos delinquentes e auto-estima. Recorrendo a 249 jovens do sexo feminino, subdivididas em grupo forense (n=93) e em grupo escolar (n=156), foram analisadas diferenças a nível de variáveis sócio-demográficas, traços psicopáticos, perturbação do comportamento, problemas de comportamento, comportamentos delituosos, auto-estima e desejabilidade social. Os resultados indicaram que as jovens do grupo forense apresentam valores significativamente mais elevados em traços psicopáticos, categoria psicopática, perturbação de comportamento, problemas de comportamento e comportamentos delituosos, mas não foram encontradas diferenças relativamente a auto-estima e desejabilidade social. Um modelo de regressão logística binária confirmou a importância dos traços psicopáticos e da categoria psicopática na predição de pertença das jovens aos grupos forense e escolar.
    2013Journal article Open access Show more
  • Different MMSE domains are associated to cognitive decline and education
    Publication . Cardoso, Sandra; Barros, Ricardo; Maroco, J. P.; Mendonça, Alexandre de; Guerreiro, Manuela
    The Mini-Mental State Examination (MMSE) is a long-established test to screen for dementia, estimate the severity and monitor the progression of cognitive impairment. The MMSE total score is dependent upon demographic factors, particularly education, but little is known about how education influences the 6 distinct MMSE cognitive domains. The present study aims to understand how the performances in the MMSE cognitive domains reflect clinical diagnosis and educational level. The study recruited 1043 participants, comprising 388 healthy controls, 360 patients with Mild Cognitive Impairment (MCI) and 295 patients with dementia. The association of the MMSE cognitive domains scores with clinical diagnosis (healthy, MCI, dementia) and educational level (primary education, middle school, high school and university/college) was analyzed with a multivariate ordinal regression model. The scores in all MMSE domains were generally higher in healthy controls as compared to patients with MCI, and higher in these as compared to patients with dementia. The MMSE domain Constructional ability was associated to the education level, the domains Orientation, Recall and Language were associated to diagnosis, Attention and calculation was associated to both education level and diagnosis, and Registration was not associated to either education or diagnosis. In conclusion, impairment in specific MMSE domains pinpoints cognitive decline, probably indicating brain areas affected by neurodegeneration, and impairment in others reflects lower education levels and the lack of acquisition of relevant schooling abilities.
    2022Journal article Open access Show more
  • Functional evaluation distinguishes MCI patients from healthy elderly people - The ADCS/MCI/ADL scale
    Publication . Pedrosa, H.; Sá, A. de; Guerreiro, Manuela; Maroco, João; Simões, Mário R.; Galasko, D.; Mendonça, Alexandre de
    Patients with MCI may present minor impairments in activities of daily living (ADL). The main objective of this work was to evaluate the ability of two versions of the Alzheimer's Disease Cooperative Study / Activities of Daily Living scale adapted for MCI patients (ADCS/MCI/ADL18 and ADCS/MCI/ADL24) to distinguish patients with MCI from healthy control subjects. Participants were 60 years or older and community dwelling: 31 control subjects, 30 aMCI patients and 33 AD patients. A protocol of neuropsychological tests, global evaluation scales, functional scales, and depressive symptoms assessment was used. Activities of balancing the cheque book, using a telephone, going shopping, taking medication regularly, finding objects, talking about current events, watching television, initiating complex activities, keeping appointments or meetings, reading, getting around outside the home and driving a car were impaired in aMCI patients. The ADCS/MCI/ADL24 scale was better than the ADCS/MCI/ADL18 scale in distinguishing aMCI patients from healthy controls (sensitivity=0.87, specificity=0.87, ROC c=0.887, cut-off point=52/53). The detection of initial functional changes with appropriate scales may contribute to the early diagnosis of MCI and the development of targeted interventions to improve everyday function or prolong independence.
    2010Journal article Restricted access Show more
  • Memory awareness in patients with major depressive disorder
    Publication . Mendes, Tiago; Cardoso, Sandra; Guerreiro, Manuela; Marôco, João Paulo.; Silva, Dina; Alves, Luísa; Schmand, Ben; Couto, Frederico Simões Do; Figueira, Maria Luísa; De Mendonça, Alexandre
    Subjective Memory Complaints (SMC) along with cognitive deficits are frequently observed in patients with Major Depressive Disorder (MDD). The relationship between SMC and objective memory performance in patients with MDD was evaluated, in comparison with patients with Mild Cognitive Impairment due to Alzheimer's Disease (MCI-AD) and healthy controls (HC).
    2021Journal article Open access Show more
  • Memory complaints are frequent but qualitatively different in young and elderly healthy people
    Publication . Ginó, Sandra; Mendes, Tiago; Maroco, João; Ribeiro, Filipa; Schmand, Ben A.; Mendonça, Alexandre de; Guerreiro, Manuela
    Background: Subjective memory complaints are frequently reported by the elderly. There is less information about the characterization of subjective memory complaints in young people. Objective: To determine different memory complaints between young and elderly people with the use of the Subjective Memory Complaints (SMC) scale. Methods: Participants were volunteers attending a health itinerant unit, a blood donor centre, a leisure centre for retired people, a senior citizens college or university. All participants were questioned about their own memory abilities using the SMC scale and assessed for the presence of depressive symptoms. Results: Nine-hundred and forty-six subjects aged 18–92 years were included in the study. The mean total score on the SMC scale was 4.89 +- 3.03, and 75.9% of the participants had at least minor complaints about their memory. Older people had more general memory complaints and reported they were more likely to become transiently confused, whereas younger people reported they were more frequently told by others that they were forgetful and would more often take notes. Conclusions: Memory complaints were frequent both in young and elderly subjects, but the detailed assessment revealed age-related differences in the type of complaints.
    2010Journal article Open access Show more