Universidade de Coimbra - UNIV-FAC-AUTOR Faculdade de Psicologia e de Ciências da Educação - PDF

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2015 Universidade de Coimbra UNIVFACAUTOR Faculdade de Psicologia e de Ciências da Educação Working memory assessment in older adults: Validation and norming studies of the Month DISSERT UC/FPCE Imke Buekenhout

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2015 Universidade de Coimbra UNIVFACAUTOR Faculdade de Psicologia e de Ciências da Educação Working memory assessment in older adults: Validation and norming studies of the Month DISSERT UC/FPCE Imke Buekenhout UNIVFACAUTOR Dissertação de Mestrado em Psicologia Clínica e da Saúde, subárea de especialização em Psicogerontologia Clínica, sob a orientação do Professor Doutor José Augusto Simões Gonçalves Leitão. And once the storm is over, you won t remember how you made it through, how you managed to survive. You won t even be sure, whether the storm is really over. But one thing is certain. When you come out of the storm, you won t be the same person who walked in. That s what this storm s all about. Haruki Murakami, Kafka on the Shore. Working memory assessment in older adults: Validation and norming studies of the Month Abstract: The present work aimed to obtain constructrelated evidence for the Month and to examine its reliability (testretest and internal consistency). We equally sought to establish normative data for use with speakers of European Portuguese. More specifically, we intended to: 1) attain convergent and discriminant validity evidence for the Month Ordering Task, studying the correlations between this task and other working memory tasks (Reading Span Task and Digit Span Backward) and between the Month and measures of constructs less related to working memory (Digit Span Forward, and measures of inhibition and processing speed derived from the Stroop Neuropsychological Screening Test); 2) analyze the Month s reliability; testretest reliability was investigated by assessing 40 participants on two different occasions (with a 1214 week interval) and internal consistency was checked by estimating Cronbach s alpha; 3) establish regressionbased norms for use with speakers of European Portuguese. The Month revealed to possess sound psychometric properties, strongly correlating with other measures of working memory and presenting nonsignificant to moderate correlations with measures of less related constructs (except for the Digit Span Forward, with which a strong correlation was unveiled). A high retest coefficient was obtained, suggesting that the Month is a temporally stable instrument. The internal consistency study revealed that the Month is an internally consistent and homogeneous scale. Linear regression analyses showed that Month performance is influenced by age, gender and years of formal education. In order to control for these influences, a regressionbased algorithm was obtained, enabling the user to transform Month scores into standardized Z scores. Key Words: Month, working memory, older adults, convergent validity, discriminant validity, testretest reliability, internal consistency, regressionbased norms. Avaliação da memória de trabalho em adultos idosos: Estudos de validação e normativos da Tarefa de Ordenação de Meses Resumo: Este trabalho teve como objetivo a análise das propriedades psicométricas da Tarefa de Ordenação de Meses e o estabelecimento de normas baseadas na regressão para uso com indivíduos cuja língua materna seja o português europeu. Mais especificamente, os objetivos desta tese são os seguintes: 1) análise da validade convergente e discriminante da Tarefa de Ordenação de Meses, através do estudo das correlações com outros instrumentos de avaliação da memória de trabalho (Tarefa de Amplitude de Leitura e Memória de Dígitos em sentido inverso) e com instrumentos que avaliam construtos menos relacionados com a memória de trabalho (Memória de Dígitos em sentido direto, e medidas de inibição e de velocidade de processamento obtidas através do Teste Stroop Neuropsicológico); 2) estudo da fiabilidade da Tarefa de Ordenação de Meses, nomeadamente a fiabilidade testereteste e a consistência interna; de forma a examinar a fiabilidade testereteste, uma amostra de 40 participantes foi avaliada duas vezes em momentos distintos (separados por um intervalo de 1214 semanas), e a consistência interna foi analisada recorrendo ao índice alfa de Cronbach; 3) por último, procuramos obter dados normativos para falantes do português europeu. Os resultados obtidos sugerem que a Tarefa de Ordenação de Meses possui boas propriedades psicométricas, apresentando fortes correlações com outras medidas de memória de trabalho e correlações fracas a moderadas com instrumentos que visam a avaliação de construtos distintos (com exceção da Memória de Dígitos em sentido direto, tendo sido obtido um coeficiente de correlação elevado). A Tarefa de Ordenação de Meses mostra ter uma boa estabilidade temporal, demonstrando também ser uma escala homogénea com boa consistência interna. Análises de regressão lineares revelaram que o desempenho na Tarefa de Ordenação de Meses é influenciado por diversas variáveis demográficas (idade, género, anos de escolaridade). De forma a poder controlar o impacto destas variáveis demográficas na avaliação da memória de trabalho através do desempenho na Tarefa de Ordenação de Meses, foram obtidas normas baseadas na regressão. Esse algoritmo permite a transformação de resultados brutos em resultados standardizados. Palavraschave: Tarefa de Ordenação de Meses, memória de trabalho, adultos idosos, validade convergente, validade discriminante, fiabilidade testereteste, consistência interna, normas baseadas na regressão. Agradecimentos A realização desta tese nunca teria sido possível sem o apoio fundamental de diversas pessoas e instituições. Correndo o risco de me alongar bastante, gostaria de aqui deixar a minha mais sincera gratidão. Ao professor Doutor José Augusto Simões Gonçalves Leitão, pela sua paciência infinita, disponibilidade para esclarecer todas as minhas dúvidas (que não foram poucas), transmissão de inúmeros conhecimentos e excelente orientação. Obrigada por me ter deixado trabalhar ao meu próprio ritmo sem nunca me pressionar. Tornouse, sem dúvida, num exemplo de rigor e de profissionalismo que procuro seguir. Aos meus pais e à minha irmã Ines. O vosso apoio e paciência foram fundamentais na realização desta tarefa aparentemente interminável. Obrigada por acreditarem em mim e por estarem sempre do meu lado. Sem vocês não estaria onde estou hoje, e espero um dia poder retribuir tudo o que fizeram por mim. À Carla, a irmã que Coimbra me deu, a melhor amiga de sempre e para sempre. Obrigada por tornares a minha vida infinitamente melhor e mais leve. Agradeçote por tudo, desde as palavras de apoio e de conforto aos momentos de loucura. Apesar de agora seguirmos caminhos diferentes, sabes que fazemos do longe o perto. Às minhas colegas de Psicogerontologia, por me terem acolhido tão bem. Gostava de dirigir o meu agradecimento sobretudo à Fabi, à Catarina e à Joana. Fabi, para além de teres sido uma fantástica colega de estágio, revelaste ser uma amiga importante. Obrigada pelas palavras de ânimo, partilhas e demonstrações de amizade. Catarina, as tuas aventuras e desventuras colocam um sorriso no meu rosto e enchem o meu coração. Joana, as nossas cartas sem fim, as discussões filosóficas e literárias e conversas sobre tudo e nada são capazes de melhorar drasticamente o meu dia. À Anaísa, por também teres desempenhado um papel fundamental no meu percurso académico. Por toda a ajuda que ofereceste, pelo companheirismo, pelas estadias na Figueira. Ao Rena, pois recebesteme sempre de braços abertos. Por teres também cuidado da minha vida social, mesmo quando eu não o queria. Por todos os passeios e todas as conversas. À Jessi, pelo contributo fundamental na pesquisa de material bibliográfico relevante. Por teres sido uma das melhores colegas de casa de sempre, pois transformaste uma simples casa de estudantes num lar. À Maria, por todos os cafézinhos, sábios conselhos e capacidade de me tranquilizar nos momentos de maior desespero. Várias pessoas foram fulcrais na procura de participantes. Assim sendo, devo um sincero agradecimento às famílias Neves, Mota, QuestroyOliveira e Ramos. Receberamme sempre de forma calorosa, sem nunca pedir nada em troca. A Ana Carvalho e a Helena Paiva foram igualmente fundamentais na procura de cobaias. Quero também deixar um agradecimento ao Agrupamento de Escolas de Carregal do Sal, em especial ao professor Hermínio Cunha, pela sua disponibilidade e por ter posto a escola à minha disposição, ao professor Fernando Milheiro pela sua genuína preocupação e pelos seus esforços no recrutamento de participantes, e à Doutora Alexandra Gaudêncio, pelo seu entusiasmo e por igualmente ter dado um contributo importante para o completamento da minha amostra. À PSP de Coimbra, à Universidade Sénior de Carregal do Sal, ao Centro Social Professora Elisa Barros Silva, ao Instituto Universitário Justiça e Paz, à Cáritas Paroquial de Oliveira do Conde e à Associação Portuguesa de Paralisia Cerebral de Viseu (pólo de Oliveira do Conde), pelo interesse neste projeto e por terem colaborado comigo. Por fim, queria agradecer, do fundo do coração, a todas as pessoas que participaram neste estudo. Obrigada pela vossa paciência e pelo tempo do vosso dia que reservaram especialmente para mim. Table of Contents Introduction... 1 I Theoretical Framework Working Memory Definition Neuroanatomical Substrates Functions and Contents Models of WM Baddeley s WM Model Cowan s EmbeddedProcesses Model WM and Aging WM and Normative Senescent Changes WM and Reduced Processing Speed WM and Loss of Inhibitory Functions WM and Reduction in Processing Resources WM and Pathological Senescent Changes WM Assessment Frequently Used WM Tasks Frequently Used WM Tasks for Research Purposes Complex Span Tasks Nback Task Frequently Used WM Tasks in Clinical Settings WM Assessment and the Elderly The Month II Aims of the Present Work III Method Participants Convergent and Discriminant Validity Studies Reliability Study Normative Data Procedure Convergent and Discriminant Validity Studies Testretest Reliability Normative Data Statistical Analyses... 26 3.1. Convergent Validity Evidence Study Discriminant Validity Evidence Study Reliability Study Influence of Demographic Characteristics on MOT performance Regressionbased norms for the MOT IV Results Convergent Validity Study Discriminant Validity Study Reliability Influence of Demographic Characteristics on MOT Performance Regressionbased Norms for the MOT V Discussion VI Conclusions Bibliographical References Appendices List of Tables Table 1. Descriptive statistics for measures of memory, inhibition and processing speed, using untransformed proportioncorrect scores and measures of speed, expressed as inverse duration in milliseconds (ms1) or syllable rate (syllables per second) Table 2. Descriptive statistics for and testretest reliability of the MOT and RST (Proportioncorrect scores were used) Table 3. Itemtotal correlations and alpha values for each administration of the MOT using the testretest sample Table 4. Itemtotal correlations and alpha values for the MOT using the normative sample Table 5. Nonhierarchical linear multiple regression analysis for variables (age, gender, years of formal education) contributing to MOT performance Table 6. Demographic structure of the normative sample and stratified descriptive statistics for the untransformed MOT proportioncorrect scores (considering the interruption criterion) Appendix I. Correlation matrix for measures of memory, inhibition and processing speed Appendix II. Hierarchical multiple regression analysis assessing the contribution of demographic variables (age, gender, years of formal education) on MOT performance Appendix III Table 1. Betweensubjects summary Appendix III Table 2. Descriptive statistics (using untransformed proportioncorrect MOT scores, considering the interruption criterion) for age categories, and pairwise comparisons between groups (mean differences) Acronyms List WM MOT RST DS DSB DSF SNST RCWpcRBWpc RCWsRBWs NCWpcNCSpc NCWsNCSs NCSs NCSsr Working Memory Month Reading Span Task Digit Span Digit Span Backward Digit Span Forward Stroop Neuropsychological Screening Test Difference in proportioncorrect scores for reading color names presented as (incongruent) colored words (RCWpc) vs. black words (RBWpc) Difference in speed while reading color names presented as (incongruent) colored words (RCWs) vs.black words (RBWs) Difference in proportioncorrect scores for naming colors presented as colored words (incongruous hue/color names) (NCWpc) vs. colored squares (NCSpc) Difference in speed for naming colors presented as colored words (NCWs) representing incongruous color names vs. colored squares Naming speed of colored squares Syllable rate (syllables per second) while naming colors presented as colored squares 1 Introduction The present work aims to obtain constructrelated evidence for the Month, as well as to study its reliability. We equally intend to establish normative data for use with speakers of European Portuguese. With age, cognitive losses and declines in memory are frequent, with the most commonly affected components being episodic and working memory (Potter & Attix, 2006). There are two forms of cognitive change associated with aging: the socalled benign changes (resulting from nonspecific histopathological brain alterations), and the malignant changes. The latter are considered atypical, and are due to the presence of specific brain pathology (Smith & Rush, 2006). According to Potter and Attix (2006), it is important to distinguish benign changes typical of normal aging from more severe problems related with progressive cognitive disorders. Mild changes that are common with age are often similar to the early signs presented by dementing illnesses. For instance, memory impairment is one of the main symptoms in dementia, whilst it also is one of the most affected domains in healthy aging (Spaan, Raaijmakers, & Jonker, 2005). Working memory (WM) is thought of as a system that is responsible for the temporary storage and manipulation of information, playing an important role in several cognitive abilities (as, for instance, problem solving, language, among others) (Ricker, AuBuchon, & Cowan, 2010; Shah & Miyake, 1996). Importantly, considering the goals of the present work, WM is one of the most altered memory components in the elderly (compromised by both benign and malignant changes). WM problems have been detected in illnesses such as Alzheimer s disease (Calderon et al., 2001; Kensinger, Shearer, Locascio, Growdon, & Corkin, 2003; Baddeley, Logie, Bressi, Della Sala, & Spinnler, 1986), Parkinson s disease (Gabrieli, Singh, Stebbins, & Goetz, 1996; Kensinger et al., 2003), dementia with Lewy bodies (Calderon et al., 2001), in cases of traumatic brain injury (McAllister, Flashman, Sparling, & Saykin, 2004; McAllister, Flashman, McDonald, & Saykin, 2006) and stroke (Kirshner & Mark, 2009). Accordingly, the study of WM should be included in the neuropsychological assessment of the elderly, as it might indicate the presence of dementia related cognitive disorders, or be relevant in the evaluation of lesions resulting from stroke and traumatic brain injuries, for example. Early (and comprehensive) assessments are important to adequately inform clinical decisions, and in order to be able to provide adequate psychosocial care and support (Spaan et al., 2005). Despite the importance of WM assessment of older patients, it is common to apply WM measures developed with younger/cognitively healthy participants to older/clinical populations. However, it is not possible to assume the reliability and validity of the WM measures when used with older or clinical populations: empirical evaluation of the candidate tasks/measures to this specific use is required (Wright & Fergadiotis, 2012). 2 In fact, WM is often assessed with tasks that might be too difficult for older and cognitively impaired individuals. Tasks that present high levels of difficulty may lead to floor effects, with participants scoring at the bottom of the measure. Complex tasks might also be demoralizing, contributing to a diminished effort (Wright & Fergadiotis, 2012). Potter and Attix (2006) refer that cognitive function amidst the elderly is quite heterogeneous: administering tests that are too difficult or too easy considering the patient s functional levels can lead to false negative and false positive errors in the process of diagnosing impairment. Almor and colleagues (Almor, Kempler, MacDonald, Andersen, & Tyler, 1999; Almor, MacDonald, Kempler, Andersen, & Tyler, 2001) suggest that WM tasks that are generally used with young participants are too difficult for patients with Alzheimer s disease (AD). The authors sought to explore the difficulty in understanding spoken language presented by mild to moderate AD patients, which is possibly caused by a WM deficit. However, due to the complexity of standardly used WM tasks, the patients could not be adequately assessed. Therefore, Almor and his team developed a new WM task, the Month (MOT), its goal being the evaluation of verbal WM. In this task, participants are asked to put into calendar sequence an increasingly long group of months that is presented to them out of calendar order. This task holds some advantages when compared to other WM instruments (which will be detailed in the theoretical framework, section 4.3.), and its use can be extended to other clinical populations/healthy senior and even younger populations, as has been demonstrated in a number of studies (Goral et al, 2011; Kljajevic, Fratini, Etxaniz, Urdaneta, & Yanguas, 2013). However, for a widespread use of the MOT to be possible, studies exploring the reliability and validity of this measure should be carried out. To our knowledge, such studies have not been implemented yet. Considering the fact that the most commonly used WM measures might not be suitable for clinical/older populations, and pondering the advantages presented by the MOT, the aim of this study is to obtain constructrelated evidence of validity, as well as reliability data for this task. If the MOT reveals to be a valid and reliable instrument, normative data for speakers of European Portuguese will equally be presented. Internal consistency will be assessed through Cronbach s alpha and testretest reliability will be verified by administering the MOT on two separate occasions (with a testing interval of 1214 weeks). Constructrelated evidence of validity will be attained by interpreting correlations with scores from other instruments. Using linear regression analyses, the contribution of age, education and gender on MOT performance will be determined, so as to establish appropriate normative data for European Portuguese speakers. The present thesis comprises six different sections. So as to foster the reader s understanding of the complexity of WM and its importance in neuropsychological assessment, a theoretical framework will be provided. Accordingly, the first part of this document will include a comprehensive 3 description of WM, as well as a brief presentation of its neuroanatomical substrates. Two important and influential WM models will be discussed: Baddeley s working memory model and Cowan s embedded processes model. The relationship between WM and aging will equally be discussed in this first section. We will explore some possible explanations for the nature of this relationship, that insidiously buildsup impairment in older adults (as, for instance, the slowing of processing speed and the inefficiency of inhibitory mechanisms). The pathological processes that may foster WM dysfunction (such as Alzheimer s disease, Parkinson s disease, dementia with Lewy bodies, traumatic brain injury, stroke) are portrayed as well, leading to the discussion of the importance of WM assessment in the elderly. We will further discuss the adequacy of some of the
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