Cognition in schizophrenia (SCZ) has been reported to be heterogeneous. Some have ascribed this to the existence of cognitive subtypes, while others have attributed heterogeneity to the types of assessments used and the implications of various research designs. In absence of a uniform standardized battery, The MATRICS (Measurement and Treatment Research to Improve Cognition in Schizophrenia) Consensus Cognitive Battery (MCCB) was developed to measure the effects of pharmacological treatment. Other neuropsychological tasks such as the Attention Network Test (ANT), Change Localization (CL), and Stop Signal Task (SST) have also been heavily researched in this population. The overall aim of this dissertation is to assess not only the participant performance on these tasks, but also the test-rest reliability of these assessments in a relatively short retest interval (14±2 days) in a Healthy Volunteer (HV) and SCZ group. In addition, the relationship between Continuous Performance Test-Identical Pairs (CPT-IP), an attention task (ANT), and working memory task (CL) was explored to examine the potential working memory (WM) component of CPT-IP. Lastly, to better understand the heterogeneity of cognition observed in SCZ, Intraindividual Variability (IIV) in performance of SST was compared in relation to other tasks. The results indicated that the MCCB has fair to excellent test-retest reliability in both groups with minimal practice effect (PE) in SCZ. Most interesting, two distinct cognitive profiles were observed: cognitively-normal and below-normal. The 4-digit condition of CPT-IP was found to be the most difficult in both groups. The primary metrics of CPT-IP lacked an association with the three primary domains of ANT in HV and SCZ. No relationship was observed between WM and CPT-IP in HV, primarily due to CL’s ceiling effect, while in SCZ, moderate to strong associations in these tasks were observed. Lastly, little to no relationship was observed between IIV and MCC domain scores in HV and SCZ. The HV group demonstrated some relationship between IIV and domains of ANT. The SCZ group failed to show similar relationships primarily due to larger inter-individual variability. Taken together, the findings of this dissertation suggest the potential for cognitive heterogeneity unrelated to PE and reliability of tasks. / 2021-10-07T00:00:00Z

Habitual (i.e., average or typical) sleep duration and sleep efficiency vary widely by demographic characteristics, including age, gender, and racial/ethnic identity. Despite a wealth of studies on demographic patterns in habitual sleep, these results are often based on cross-sectional surveys, which ask participants to retrospectively recall their "typical" or "recent" sleep. Yet, sleep is a highly dynamic behavior and may fluctuate substantially from night-to-night. This intraindividual variability (IIV) in sleep/wake patterns can be captured a multitude of ways, most commonly by using formula-based calculations. Although there is growing attention on the importance of IIV in sleep, findings on demographic differences are still inconclusive, and there are no guidelines for typical values of IIV in sleep. The present study quantitatively synthesized 8 international data sets (N = 2847 participants, 29,832 total days of sleep data), focusing on examining age, gender, and racial/ethnic identity differences in IIV in sleep measured via sleep diaries, actigraphy, and electroencephalography. Sleep duration and sleep efficiency varied widely from night-to-night within people (duration: 64-119 minutes; efficiency: 5-8%). Different metrics of IIV were strongly correlated within and across sleep measurement types. Younger adults had more IIV in diary and actigraphy sleep duration. Gender differences in IIV in sleep were inconsistent, and non-Hispanic/Latinx and White adults had less IIV in sleep compared to other racial/ethnic minority groups. Results emphasize the importance of assessing IIV in sleep, and show that even among healthy sleepers, sleep varies from night-to-night. Like mean sleep, there may also be disparities in IIV in sleep by demographic characteristics, highlighting a need for targeted interventions to stabilize sleep and improve health.

O presente estudo teve como objetivo investigar a associação da trajetória e do nível de estabilização ao final da fase de estabilização no desempenho da fase de adaptação. Participaram do experimento cem sujeitos de ambos os sexos, entre 10 e 12 anos de idade. Os sujeitos realizaram uma tarefa seriada de rastreamento de sinais luminosos. O experimento constou de duas fases: estabilização (120 tentativas) e adaptação (40 tentativas). Para a fase de estabilização foi utilizada uma sequência de 5 estímulos (4-2-5-3-1) com intervalo de 800 ms entre os mesmos. Para a fase de adaptação foram alterados: o intervalo entre os estímulos (700 ms) e a ordem dos estímulos (4-2-5-1-3). As variáveis do estudo foram: a) nível de estabilização alcançado ao final da fase de estabilização, b) trajetória do desempenho individual na fase de estabilização, e c) trajetória do desempenho individual na fase de adaptação. As análises estatísticas constaram de: análise de variância não paramétrica de Friedman - para detectar as diferenças no desempenho entre os blocos de tentativas; análise de cluster - para agregar os sujeitos com desempenho semelhante tanto na fase de estabilização (final e trajetória) quanto de adaptação (trajetória); análise de correlação por meio do coeficiente de contingência - para analisar a relação entre o desempenho na adaptação e os níveis de estabilização (final e trajetória). A análise com todos os sujeitos indicou: a) melhora do desempenho a partir de 50 tentativas de prática e manutenção do novo nível de desempenho ao longo da fase de estabilização e b) com a modificação na tarefa o desempenho diminuiu, mas voltou aos mesmos patamares do final da estabilização após 30 tentativas. A partir da análise de cluster os participantes foram agrupados em 6 subgrupos para o nível de estabilização final (CO-C; 1AO; 1A-2AO; 2A-3AO; 3A; 4A-5A) e 2 subgrupos para as trajetórias ao longo da fase de estabilização (C-1A; 1A-5A). Os níveis de estabilização final e da trajetória ao longo da estabilização apresentaram-se associados ao desempenho da fase de adaptação. Mais especificamente, foi observado que o subgrupo com trajetórias apenas com respostas corretas ao longo da fase de estabilização manteve o mesmo nível de desempenho na fase de adaptação. No subgrupo com trajetórias com respostas antecipatórias ao longo da fase de estabilização, 60% dos sujeitos mantiveram o mesmo nível de desempenho na fase de adaptação e os demais apresentaram trajetórias com respostas predominantemente corretas. Além disso, considerando o nível de estabilização ao final da fase de estabilização, os resultados permitiram discutir que é necessário alcançar pelo menos três respostas antecipatórias na sequência para apresentar respostas antecipatórias na adaptação, pois os subgrupos com menos de 3RA na composição das suas sequências apresentaram apenas respostas corretas na adaptação. Com base nestes resultados, pode-se inferir que parte da heterogeneidade do desempenho apresentado na fase de adaptação esta associado às diferenças individuais, visto que sujeitos submetidos ao mesmo regime de prática apresentaram comportamentos díspares ao longo da fase de estabilização e adaptação / The present study aimed to investigate the association of the trajectory and the level stabilization at the end of the stabilization phase on the performance of the adaptation phase. A hundred subjects of both gender, between 10 and 12 years old, participated in the experiment. Subjects performed a serial tracking task light signals. The experiment consisted of two phases: stabilization (120 trials) and adaptation (40 trials). For the stabilization phase a 5 stimulus sequence (4-2-5-3-1) with an interval of 800 ms between them. For the adaptation phase were changed: the interval between stimulus (700 ms) and order of stimulus (4-2-5-1-3). The variables of the study were: a) stabilization level reached at the end of the stabilization phase, b) trajectory of individual performance in the stabilization phase. These variables were based on results in the stabilization phase. Statistical analyzes consisted of: non-parametric analysis of variance Friedman - to detect differences in performance between blocks of trials, cluster analysis - to aggregate the subjects with similar performance both in the stabilization phase (final and trajectory) and adaptation (trajectory); correlation analysis through contingency coefficient - to examine the relationship between performance in adaptation and the stabilization levels (final and trajectory). The analysis with all subjects showed: a) performance improvement from 50 trials of practice and maintain the new level of performance throughout the stabilization phase and b) with changes in the task performance decreased, but returned to the same levels as the end of the stabilization after 30 attempts. From the cluster analysis participants were grouped into 6 subgroups for final stabilization level (CO-C; 1AO; 1A-2AO; 3AO-2A, 3A, 4A, 5A), and 2 subgroups for trajectories along the stabilization phase (C-1A, 1A-5A). Final stabilization level and trajectory along the stabilization presented themselves associated with the performance in the adaptation phase. More specifically, it was observed that the subgroup trajectory with only correct answers along the stabilization phase showed no change in performance in adaptation phase. In the subgroup trajectories with only anticipatory answers along the stabilization phase, maintained the same level of performance in the adaptation phase and the others presented trajectories with correct answers. Moreover, considering the level of stabilization at the end of the stabilization phase, the results allowed to discuss that is needed to achieve at least three anticipatory responses in the sequence to display anticipatory responses in adaptation, because the subgroups under 3RA in the composition of their sequences showed only correct responses in adaptation. Based on these results, can be inferred that some of the heterogeneity of performance presented in the adaptation phase is associated with the individual differences, whereas subjects submitted to the same practice regimen showed disparate behaviors during the stabilization and adaptation phase

O presente estudo teve como objetivo investigar a associação da trajetória e do nível de estabilização ao final da fase de estabilização no desempenho da fase de adaptação. Participaram do experimento cem sujeitos de ambos os sexos, entre 10 e 12 anos de idade. Os sujeitos realizaram uma tarefa seriada de rastreamento de sinais luminosos. O experimento constou de duas fases: estabilização (120 tentativas) e adaptação (40 tentativas). Para a fase de estabilização foi utilizada uma sequência de 5 estímulos (4-2-5-3-1) com intervalo de 800 ms entre os mesmos. Para a fase de adaptação foram alterados: o intervalo entre os estímulos (700 ms) e a ordem dos estímulos (4-2-5-1-3). As variáveis do estudo foram: a) nível de estabilização alcançado ao final da fase de estabilização, b) trajetória do desempenho individual na fase de estabilização, e c) trajetória do desempenho individual na fase de adaptação. As análises estatísticas constaram de: análise de variância não paramétrica de Friedman - para detectar as diferenças no desempenho entre os blocos de tentativas; análise de cluster - para agregar os sujeitos com desempenho semelhante tanto na fase de estabilização (final e trajetória) quanto de adaptação (trajetória); análise de correlação por meio do coeficiente de contingência - para analisar a relação entre o desempenho na adaptação e os níveis de estabilização (final e trajetória). A análise com todos os sujeitos indicou: a) melhora do desempenho a partir de 50 tentativas de prática e manutenção do novo nível de desempenho ao longo da fase de estabilização e b) com a modificação na tarefa o desempenho diminuiu, mas voltou aos mesmos patamares do final da estabilização após 30 tentativas. A partir da análise de cluster os participantes foram agrupados em 6 subgrupos para o nível de estabilização final (CO-C; 1AO; 1A-2AO; 2A-3AO; 3A; 4A-5A) e 2 subgrupos para as trajetórias ao longo da fase de estabilização (C-1A; 1A-5A). Os níveis de estabilização final e da trajetória ao longo da estabilização apresentaram-se associados ao desempenho da fase de adaptação. Mais especificamente, foi observado que o subgrupo com trajetórias apenas com respostas corretas ao longo da fase de estabilização manteve o mesmo nível de desempenho na fase de adaptação. No subgrupo com trajetórias com respostas antecipatórias ao longo da fase de estabilização, 60% dos sujeitos mantiveram o mesmo nível de desempenho na fase de adaptação e os demais apresentaram trajetórias com respostas predominantemente corretas. Além disso, considerando o nível de estabilização ao final da fase de estabilização, os resultados permitiram discutir que é necessário alcançar pelo menos três respostas antecipatórias na sequência para apresentar respostas antecipatórias na adaptação, pois os subgrupos com menos de 3RA na composição das suas sequências apresentaram apenas respostas corretas na adaptação. Com base nestes resultados, pode-se inferir que parte da heterogeneidade do desempenho apresentado na fase de adaptação esta associado às diferenças individuais, visto que sujeitos submetidos ao mesmo regime de prática apresentaram comportamentos díspares ao longo da fase de estabilização e adaptação / The present study aimed to investigate the association of the trajectory and the level stabilization at the end of the stabilization phase on the performance of the adaptation phase. A hundred subjects of both gender, between 10 and 12 years old, participated in the experiment. Subjects performed a serial tracking task light signals. The experiment consisted of two phases: stabilization (120 trials) and adaptation (40 trials). For the stabilization phase a 5 stimulus sequence (4-2-5-3-1) with an interval of 800 ms between them. For the adaptation phase were changed: the interval between stimulus (700 ms) and order of stimulus (4-2-5-1-3). The variables of the study were: a) stabilization level reached at the end of the stabilization phase, b) trajectory of individual performance in the stabilization phase. These variables were based on results in the stabilization phase. Statistical analyzes consisted of: non-parametric analysis of variance Friedman - to detect differences in performance between blocks of trials, cluster analysis - to aggregate the subjects with similar performance both in the stabilization phase (final and trajectory) and adaptation (trajectory); correlation analysis through contingency coefficient - to examine the relationship between performance in adaptation and the stabilization levels (final and trajectory). The analysis with all subjects showed: a) performance improvement from 50 trials of practice and maintain the new level of performance throughout the stabilization phase and b) with changes in the task performance decreased, but returned to the same levels as the end of the stabilization after 30 attempts. From the cluster analysis participants were grouped into 6 subgroups for final stabilization level (CO-C; 1AO; 1A-2AO; 3AO-2A, 3A, 4A, 5A), and 2 subgroups for trajectories along the stabilization phase (C-1A, 1A-5A). Final stabilization level and trajectory along the stabilization presented themselves associated with the performance in the adaptation phase. More specifically, it was observed that the subgroup trajectory with only correct answers along the stabilization phase showed no change in performance in adaptation phase. In the subgroup trajectories with only anticipatory answers along the stabilization phase, maintained the same level of performance in the adaptation phase and the others presented trajectories with correct answers. Moreover, considering the level of stabilization at the end of the stabilization phase, the results allowed to discuss that is needed to achieve at least three anticipatory responses in the sequence to display anticipatory responses in adaptation, because the subgroups under 3RA in the composition of their sequences showed only correct responses in adaptation. Based on these results, can be inferred that some of the heterogeneity of performance presented in the adaptation phase is associated with the individual differences, whereas subjects submitted to the same practice regimen showed disparate behaviors during the stabilization and adaptation phase

O objetivo do presente estudo foi investigar se os níveis de estabilização alcançados no final do processo de aquisição e nos canais de desempenho modificam a probabilidade de um dos dois processos envolvidos no aumento de complexidade em aprendizagem motora - modularização e adaptação - ocorrer, quando novos componentes são inseridos na tarefa já aprendida, e sua influência na aprendizagem da tarefa com novos componentes. Cento e cinquenta e três sujeitos de ambos os sexos, entre 10 e 13 anos de idade, realizaram uma tarefa seriada de rastreamento de sinais luminosos. O experimento constou de duas fases: estabilização e adaptação. Três grupos foram formados de acordo com critérios de desempenho a ser alcançados na estabilização: três séries consecutivas de respostas corretas, uma série de respostas antecipatórias e três séries de respostas antecipatórias, numa tarefa seriada composta de cinco estímulos. A fase de adaptação, igual para todos os grupos, ocorreu até o alcance de uma série de respostas antecipatórias numa tarefa com seis estímulos. Os resultados mostraram a ocorrência de ambos os processos: adaptativo e modularização, em 84% e 16% dos sujeitos, respectivamente. Os sujeitos do que alcançaram respostas antecipatórias foram posteriormente divididos em subgrupos com base na estabilidade interindividual da mudança intra-individual nos canais de desempenho ao longo da fase de estabilização. Foram definidos 4 subgrupos: estável no canal superior; estável no canal inferior; com tendência a mudança ascendente; e com oscilação. Os resultados da análise de regressão logística permitiram inferir que o subgrupo estável no canal superior da consistência do desempenho da sequência em respostas antecipatórias tem quatro vezes mais probabilidade de utilizar o processo de modularização do que o subgrupo estável no canal inferior, quando novos componentes são inseridos na tarefa já aprendida. Além disso, foi possível identificar que os sujeitos que utilizaram o processo de modularização necessitaram de uma menor quantidade de tentativas para a aprendizagem da nova tarefa / The purpose of this study was to investigate whether levels of stabilization achieved by the end of the acquisition process and performance channels modify the probability of occurrence of one of the two processes involved in the increase of complexity in motor learning - modularization and adaptation - when new components are inserted into the task already learned, and their influence on the learning of the task with new components. One hundred and fifty-three subjects of both sexes, between 10 and 13 years of age, performed a serial tracking task of luminous stimuli. The experiment consisted of two phases: stabilization and adaptation. Three groups were formed according to performance criteria to be achieved in the stabilization phase: three consecutive series of correct responses (group G_3C), a series of antecipatory responses (G_1A group) and three series of anticipatory responses (group G_3A) in a task with five stimuli. The adaptation phase, the same for all groups, took place until the achievement of a series of anticipatory responses in a task with six stimuli. The results showed the occurrence of both processes: adaptive and modularization, in 84% and 16% of the subjects, respectively. The subjects of G_1A and G_3A were afterwards divided into subgroups based on the interindividual stability of intra-individual change in the performance channels during the stabilization phase. Four groups were established: stable in the upper channel, stable in the lower channel, upward moving tendency, and oscillation groups. Based on the results of binary logistic regression analysis it was observed that the stable upper channel subgroup in consistency of the sequence in anticipatory responses is four times more likely to use the process of modularization in relation to the stable lower channel subgroup, when new components are inserted into the task already learned. It was also possible to identify that the subjects who used the process of modularization needed fewer attempts to learn the new task

O objetivo do presente estudo foi investigar se os níveis de estabilização alcançados no final do processo de aquisição e nos canais de desempenho modificam a probabilidade de um dos dois processos envolvidos no aumento de complexidade em aprendizagem motora - modularização e adaptação - ocorrer, quando novos componentes são inseridos na tarefa já aprendida, e sua influência na aprendizagem da tarefa com novos componentes. Cento e cinquenta e três sujeitos de ambos os sexos, entre 10 e 13 anos de idade, realizaram uma tarefa seriada de rastreamento de sinais luminosos. O experimento constou de duas fases: estabilização e adaptação. Três grupos foram formados de acordo com critérios de desempenho a ser alcançados na estabilização: três séries consecutivas de respostas corretas, uma série de respostas antecipatórias e três séries de respostas antecipatórias, numa tarefa seriada composta de cinco estímulos. A fase de adaptação, igual para todos os grupos, ocorreu até o alcance de uma série de respostas antecipatórias numa tarefa com seis estímulos. Os resultados mostraram a ocorrência de ambos os processos: adaptativo e modularização, em 84% e 16% dos sujeitos, respectivamente. Os sujeitos do que alcançaram respostas antecipatórias foram posteriormente divididos em subgrupos com base na estabilidade interindividual da mudança intra-individual nos canais de desempenho ao longo da fase de estabilização. Foram definidos 4 subgrupos: estável no canal superior; estável no canal inferior; com tendência a mudança ascendente; e com oscilação. Os resultados da análise de regressão logística permitiram inferir que o subgrupo estável no canal superior da consistência do desempenho da sequência em respostas antecipatórias tem quatro vezes mais probabilidade de utilizar o processo de modularização do que o subgrupo estável no canal inferior, quando novos componentes são inseridos na tarefa já aprendida. Além disso, foi possível identificar que os sujeitos que utilizaram o processo de modularização necessitaram de uma menor quantidade de tentativas para a aprendizagem da nova tarefa / The purpose of this study was to investigate whether levels of stabilization achieved by the end of the acquisition process and performance channels modify the probability of occurrence of one of the two processes involved in the increase of complexity in motor learning - modularization and adaptation - when new components are inserted into the task already learned, and their influence on the learning of the task with new components. One hundred and fifty-three subjects of both sexes, between 10 and 13 years of age, performed a serial tracking task of luminous stimuli. The experiment consisted of two phases: stabilization and adaptation. Three groups were formed according to performance criteria to be achieved in the stabilization phase: three consecutive series of correct responses (group G_3C), a series of antecipatory responses (G_1A group) and three series of anticipatory responses (group G_3A) in a task with five stimuli. The adaptation phase, the same for all groups, took place until the achievement of a series of anticipatory responses in a task with six stimuli. The results showed the occurrence of both processes: adaptive and modularization, in 84% and 16% of the subjects, respectively. The subjects of G_1A and G_3A were afterwards divided into subgroups based on the interindividual stability of intra-individual change in the performance channels during the stabilization phase. Four groups were established: stable in the upper channel, stable in the lower channel, upward moving tendency, and oscillation groups. Based on the results of binary logistic regression analysis it was observed that the stable upper channel subgroup in consistency of the sequence in anticipatory responses is four times more likely to use the process of modularization in relation to the stable lower channel subgroup, when new components are inserted into the task already learned. It was also possible to identify that the subjects who used the process of modularization needed fewer attempts to learn the new task

Les recherches sur le vieillissement ont montré que la variabilité intra-individuelle (VII) du fonctionnement cognitif (dispersion et inconsistance) augmente avec l’âge. La VII pourrait jouer un rôle central dans la compréhension des changements cognitifs observés chez la personne âgée. Le but de cette recherche a été d’évaluer l’apport de la VII pour expliquer les différences d’efficience cognitive entre personnes âgées. Les relations entre deux formes de VII, dispersion (VII des scores entre plusieurs tests cognitifs) et inconsistance (VII des temps de réponse (TR) entre les essais à une tâche de contrôle cognitif), et l’efficience cognitive, ont été évaluées auprès d’un groupe d’adultes âgés de 61 ans et plus. La tâche de contrôle AX-cpt utilisée dans cette étude permet l’évaluation de processus de contrôle cognitif distincts (contrôle réactif et contrôle proactif). L’augmentation de la dispersion était associée à une diminution de la vitesse de traitement, de la capacité de la mémoire épisodique et de l’état cognitif plus général. L’augmentation de l’inconsistance semble traduire une difficulté supérieure associée à des capacités de maintien de l’information contextuelle et de résistance à l’interférence moins préservées. Toutefois, l’inconsistance pourrait exprimer une évolution positive de la cognition. Les fluctuations intra-individuelles du comportement paraissent être les caractéristiques d’un fonctionnement normal. L’irrégularité de l’instabilité temporelle des TR aux essais successifs d’une même tâche semble être un indicateur pertinent dans l’étude de la VII pour rendre compte d’une diminution de l’efficience cognitive. L’étude de la VII de la performance semble donc être une approche fructueuse pour expliquer la variabilité interindividuelle chez la personne âgée et prédire d’éventuels changements cognitifs / Aging research shows an age-related increase in intraindividual variability in cognitive functioning (dispersion and inconsistency). Intraindividual variability would play a central role in understanding cognitive changes in older adults. The purpose of the present research was to examine the contribution of the intraindividual variability study, in order to explain differences in cognitive efficiency between older adults. The relationship between two forms of intraindividual variability, dispersion (variability in scores across several cognitive tests) and inconsistency (variability in response time (RT) across trials in a cognitive control task), and the cognitive efficiency, was estimated in a sample of adults aged from 61 years and older. The control task AX-cpt used in this study allows the evaluation of distinct cognitive control process (proactive and reactive control). The increase in dispersion was associated with a decrease in processing speed, episodic memory ability and the more general cognitive state. The increase in inconsistency seems related to a difficulty of a cognitive system whose capacities of context information maintenance, and resistance to interference, are less preserved. However, the inconsistency could also reveal a positive evolution of cognition. Intraindividual fluctuations in behavior appear to be the characteristics of normal functioning. The irregularity of temporal instability of successive trials response times, seems to be a valid cue of the decrease in cognitive efficiency. The study of intraindividual variability in performance seems to be a fruitful approach to explain the variability between individuals observed in the elderly, and to predict possible cognitive changes.

Objective: The purpose of this dissertation was to determine whether measures of reaction time inconsistency (RTI) can be applied clinically to detect cognitive impairment in older adults. Methods: Data were obtained from the Victoria Longitudinal Study (VLS), a longitudinal study of healthy aging, and PREVENT, a multivariate study of risk factors for Alzheimer’s disease. Study 1 examined effects of task complexity and computational approach on the association between RTI and physical and cognitive functioning in participants of the VLS. Study 2 assembled normative data from the VLS and standardized RTI data from an independent VLS cohort against these normative data. Significant Study 1 findings were replicated in Study 2 using the obtained RTI T-Scores, and the clinical utility of results were evaluated using stratum specific likelihood ratios (SSLRs). Study 3 replicated Study 2 analyses in data from PREVENT. Results: Results of Study 1 identified four operationalizations of RTI from a choice reaction task that yielded consistent significant associations with cross-sectional cognitive performance. Consistent associations were not observed between these scores and cognitive change or performance on measures of physical functioning. Study 2 replicated Study 1 findings in an independent sample using RTI T-Scores. SSLRs supported the clinical utility of measures of RTI for detecting prevalent cognitive impairment. Study 3 replicated findings from Study 2, but SSLRs indicated that only low RTI scores yielded associations of sufficient reliability for clinical interpretation. Consistent with Study 1 and Study 2, associations between RTI T-Scores and measures of physical function were nonsignificant. Conclusions: Low RTI T-Scores were shown across two samples to be associated with a clinically meaningful reduction in the odds of cognitive impairment. Further research is needed in order to clarify the utility of high RTI scores for positive prediction of cognitive impairment. / Graduate

No description available.

Musicians can develop and suffer from playing-related musculoskeletal disorders (PRMDs) with pianists being a group of instrumentalists that experience a higher occurrence of PRMDs in comparison with other musicians. One cause of PRMDs is posture. The Alexander Technique (AT) is a popular somatic method among musicians that purports to alter its students’ postural and movement behaviour. Such changes may be beneficial in improving music performance. However, there is a lack of quantitative research to offer support for the effectiveness of the AT in altering posture in musicians, especially in pianists. To address this issue, four studies were conducted. The first study addressed the AT alone to determine what postural changes could be expected following lessons in the AT. Findings of this study showed that changes include a larger craniovertebral angle, head tilt, and head-neck-trunk angle as well as smaller trunk, thoracic, and thoracolumbar angles. The second study addressed variability in individual pianists’ postures and its implications for intervention studies. The results of this study demonstrated that within-person variability is present in posture between performances but does not vary widely enough to exhibit inconsistent posture across measurements. The third study examined the effects of 10 AT lessons on pianists’ postures. Findings showed that, in comparison with their pre-lesson measurements, pianists demonstrate a postural pattern of larger craniovertebral and head-neck-trunk angles as well as smaller trunk, thoracic, and thoracolumbar angles in both the post-test and follow-up tests. The fourth study explored the relationship between pianists’ perceptions of their posture and their application of the AT with quantitatively measured changes in their posture. The results of this study showed that participant perception and reported application of the AT does not necessarily always reflect the postural changes that have occurred.