跌倒和肌肉減少症是威脅老年人身體健康和生命安全的兩個重要問題。肌肉減少症所致的肌肉力量減弱和平衡能力下降是導致老年人跌倒的最主要原因。老年人跌倒最普遍和最嚴重的後果是脆性骨折。跌倒所致的脆性骨折是常見老年病，同時也是導致老年人生活品質下降和死亡的最主要原因之一。高頻低幅振動(LMHFV)是一種非侵入性生物物理干預手段，通過給予全身物理震動刺激，可有效提高肌肉功能和改善骨質。由此推測高頻低幅振動治療有望應用於預防跌倒/骨折及延緩肌肉減少。 / 本研究的目的在於，採用臨床隨機對照研究方法，通過對社區老年人進行高頻低幅振動治療，探索高頻低幅振動治療在預防跌倒/骨折、降低骨折發生率以及延緩肌肉量下降的作用。本研究假設高頻低幅振動治療可有效提高肌肉力量和改善骨質，從而降低骨折風險、跌倒率以及骨折發生率。本研究將分成兩部分進行以驗證此假說。 / 第一部分研究中，710名60歲或以上的社區老年人按社區中心為單位隨機分成振動治療組和對照組。振動治療組給予35Hz，0.3g的振動治療，並以每天20分鐘，每週5 天，持續18 個月；對照組則如常生活而不予振動治療。18個月治療過程中，振動治療組的跌倒率低於對照組46% (p=0.001)。同時，治療組的在平衡力測試中的反應時間、移動速度，和最遠移動距離也都有明顯改善 (所有指標 p<0.001）。在高頻低幅振動治療停止一年後，振動治療組的主導腿和非主導腿肌肉力量仍高於接受振動治療前 (p=0.029, p=0.002)。在平衡力測試中，治療組的反應時間、移動速度以及最遠移動距離也明顯優於對照組 (p=0.001，p=0.014，p=0.007)。在停止治療的一年期間，兩組受試者的肌肉力量，平衡能力以及生活品質均有下降的趨勢，但兩組的下降率並無明顯的差異。 / 第二部分的設計是基於第一部分的研究成果，目的在於更深入研究高頻低幅振動治療對肌肉功能、肌肉量以及肌肉質素的影響。60名社區老人隨機分成對照組和振動治療組。振動治療組給予35Hz，0.3g的高頻低幅振動治療，並以每天20分鐘，每週5天，持續9個月; 對照組則如常生活而不予振動治療。9個月後，治療組的主導腿和非主導腿的肌肉力量明顯高於對照組 (p<0.001，p=0.003)。在用以評估肌肉力量以及平衡力的計時起立坐下測試中，振動治療組用以完成連串起立及坐下動作的時間明顯低於對照組 (p=0.009)。振動治療組的下肢功能尺度問卷評估結果也明顯優於對照組 (p=0.002)。雖然兩組間的身體成份及肌電圖測試結果並無明顯差異，但治療組的肌肉量和肌電圖平均頻率均有上升的趨勢。而且，在兩部分實驗中，受試者對高頻低幅振動治療均有良好的耐受性，目前並沒有發現對受試者身體產生不利影響。因此，高頻低幅振動治療可安全地應用於社區老年人。 / 總括而言研究結果證明高頻低幅振動治療可明顯降低老年人跌倒發生率。9至18個月的振動治療可明顯改善老年人下肢功能和平衡力。在完成為期18個月高頻低幅振動治療後的1年，肌肉功能仍高於對照組，表明高頻低幅振動治療具有長期療效。因此，高頻低幅振動治療應在社區推廣作為老年人跌倒的預防方案之一。 / Fall and sarcopenia are two major problems among elderly. Poor muscle strength and balancing ability resulted from sarcopenia are the major causes of fall incidences. Fragility fracture is one of the most common and serious consequences of falls, which accounts for most of the deaths, as well as morbidity and poor quality of life. Low magnitude high frequency vibration (LMHFV) treatment is a non-invasive biophysical modality to provide a whole-body mechanical stimulation, which was previously shown to improve muscle performance and bone quality implying the potential application for fall/fracture prevention and reducing muscle loss. / The objectives of this study were to conduct prospective randomized controlled clinical trials to investigate the effect of LMHFV treatment on fall/fracture prevention, fracture risks and muscle loss among community elderly. It was hypothesized that LMHFV treatment could enhance muscle performance and bone quality, thus reducing the fracture risks, fall incidence and fracture rate. Two parts of studies were designed to testify the hypotheses. / In the Part I study, a total of 710 community elderly who were aged 60 years or above were recruited and randomized into vibration or control group on center-basis. The subjects in vibration group received LMHFV treatment (35Hz, 0.3g) 20min/day and 5days/week for 18 months, while control group remained sedentary. During the 18-month study period, the vibration group had reported 46% lower fall incidence rate when compared with control group (p=0.001). Significant improvements were found in reaction time, movement velocity and maximum excursion of balancing ability assessment, and also the quadriceps muscle strength (p<0.001 to all). After ceasing the LMHFV for 1 year, the muscle strength of dominant and non-dominant legs in vibration group were still significantly better than the baseline assessed before intervention (p=0.029 and 0.002 respectively), as compared with the control. In balancing ability test, the reaction time, movement velocity and maximum excursion of vibration group also remained significantly improved, as compared with the control group (p=0.001, 0.014 and 0.007 respectively). During the 1 year post-intervention period, both groups had shown a decreasing trend of muscle strength, balancing ability and quality of life but the rate of changes were not significantly different between two groups. / With reference to the results of Part I study, the Part II study was designed to investigate further the effects of LMHFV on muscle performance, mass and quality. 60 community elderly were recruited and randomized into either vibration or control group. Vibration group subjects received LMHFV treatment (35Hz, 0.3g) 20min/day, 5days/week for 9 months, while control group remained sedentary. Significant enhancement of dominant and non-dominant leg muscle strength was observed in the vibration group after 9 months LMHFV (p<0.001 and =0.003 respectively). In the chair rising test assessing muscle power and balancing ability, vibration group showed significantly shorter time needed for sit-to-stand cycles than the control (p=0.009). Significant increase of the lower extremity functional scale was also observed in the vibration group (p=0.002). No significant findings were found in the body composition and vibromyography (VMG) assessment, however, a trend of increasing lean mass and VMG mean frequency were observed. Also, minimal adverse effects were documented in both parts of study; all subjects were well-tolerated for LMHFV treatment. LMHFV is therefore safe and applicable to elderly in the community setting. / LMHFV was demonstrated to reduce fall incidences significantly. Significant effects on improving lower limbs function and balancing ability were observed as early as 9 months after treatment. Enhancement of muscle performance still remained significant 1 year after completion of 18-month LMHFV treatment, indicating strong residual effects of LMHFV. Use of LMHFV in the community as an effective fall prevention program is recommended. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Li, Chi Yu. / Thesis (Ph.D.) Chinese University of Hong Kong, 2014. / Includes bibliographical references (leaves 154-167). / Abstracts also in Chinese.

O presente estudo teve como objetivo geral validar a Escala de Avaliação do Risco de Quedas (EARQUE) em pessoas idosas que vivem na comunidade e, como específicos avaliar a validade de face e de conteúdo da EARQUE por especialistas (juízes) da área; a validade semântica da EARQUE na população-alvo e a validade de critério concorrente da EARQUE, a partir QuickScreen® como referência padrão. Realizou-se um estudo transversal, do tipo metodológico. Para a construção e validação do instrumento de rastreio do risco de quedas na pessoa idosa que vivem na comunidade, empregaram-se os procedimentos propostos por Pasquali (2010), a saber: teórico, empírico e analítico. O presente estudo enfatizou a análise teórica dos itens (última parte dos procedimentos teóricos), os procedimentos empíricos e analíticos. Cabe destacar que a construção da EARQUE foi realizada em estudo anterior, no entanto, neste estudo passou por um refinamento antes de prosseguir com a análise teórica. A análise teórica envolve dois momentos. No primeiro, na análise de validade de face e de conteúdo, foram eleitos juízes, ou seja, especialistas na área de saúde da pessoa idosa e do método em questão, os quais julgaram se os itens estavam ou não relacionados ao construto risco de quedas em pessoas idosas. Já no segundo, na análise semântica, a escala foi aplicada em 20 pessoas idosas selecionadas por conveniência no sentido de verificar se todos os itens eram compreensíveis para as mesmas. No delineamento principal, ou seja, nos procedimentos empíricos foi realizado um estudo do tipo Screening avaliativo, de delineamento transversal. A amostra desta etapa foi composta por 854 pessoas idosas. Além da versão piloto da EARQUE, foi aplicado o instrumento QuickScreen® como padrão-ouro. Os idosos foram divididos em dois grupos (I e II) conforme resultados do QuickScreen®, distribuídos da seguinte forma: idosos que pontuaram de 0 a 3 fatores de risco foram alocados para o Grupo I (grupo controle) e aqueles que pontuaram 4 ou mais foram alocados para o Grupo II (grupo de risco (casos). Com a finalidade de caracterizar a amostra, foram realizadas análises descritivas, utilizando medidas de tendência central (média e mediana), de variabilidade (desvio padrão) e distribuição de frequência. Para verificar diferenças de proporções entre os itens da EARQUE com os grupos obtidos a partir da aplicação do QuickScreen® foi utilizado o teste qui-quadrado (X2). Como medida de efeito foi empregada a razão de prevalência (RP) e seu respectivo Intervalo de Confiança a 95% (IC95%). Foram consideradas associações significativas àquelas que apresentavam valor de p0,05. A terceira etapa consistiu na realização de análises multivariadas por regressão logística, com o objetivo de identificar a associação entre os vários itens da EARQUE e o maior risco de quedas em pessoas idosas. Assim, inicialmente todas as variáveis da EARQUE foram incluídas na análise multivariada, e à medida que as variáveis se associavam aos itens do QuickScreen® (p0,05), estas eram selecionadas para novas análises multivariadas, consequentemente, as que apresentaram valor de p<0,05 permaneceram no modelo final da escala. Por fim, para avaliação da validade da EARQUE foram utilizadas medidas de precisão: sensibilidade, especificidade, valor preditivo positivo e valor preditivo negativo. Para representação dos valores de sensibilidade e especificidade e para identificação do melhor ponto de corte, utilizou-se a curva ROC (Receiver Operating Characteritic). Os dados foram organizados no Excel e analisados no software estatístico Med Calc versão 16.4.1. Para todas as análises realizadas considerou-se nível de significância de 5%. Ao final dos procedimentos teóricos, a EARQUE dispunha de 44 itens. Com relação às características sociodemográficas, a maioria das pessoas idosas era do sexo feminino (492; 57,6%), com média de idade de 71,87 anos. Após análises comparativas entre os grupos, 27 itens foram inseridos no modelo de regressão. Por fim, nas análises multivariadas por regressão logística, evidenciou-se que apenas 10 itens da EARQUE contribuíram para o maior risco de quedas em pessoas idosas e foram eles: queda anterior, uso de dispositivo de auxílio à marcha, polifarmácia, uso de psicotrópicos, dificuldade para subir ou descer uma ladeira, dificuldade para andar 100 metros, déficit visual e auditivo, baixa atividade física e ambiente mal iluminado. Este modelo de avaliação de risco assume valores de sensibilidade de 91,3% e especificidade de 73,4%. A EARQUE se caracteriza como instrumento válido, simples, de baixo custo e de fácil e rápida aplicação, podendo ser empregado por todos os profissionais de saúde da atenção básica, inclusive por agentes comunitários de saúde, o que se configura como uma contribuição inédita. Dessa forma, esta ferramenta discrimina pessoas idosas com menor e maior risco de quedas e, poderá indicar a necessidade de uma avaliação mais abrangente e mais detalhada, conforme sua classificação de risco - 0 a 2 pontos: baixo risco de quedas; 3 pontos: moderado risco de quedas e 4 ou mais pontos: alto risco de quedas. / The main objective of the present study was to validate the Risk of Falling Evaluative Scale (EARQUE) in elderly people that live in the community and its specific aims were to evaluate the EARQUE face and content validity by experts (judges) of the field; the EARQUE semantic validity in the target population; the EARQUE concurrent validity associating its results with the results obtained from the QuickScreen® application. A methodological cross-sectional study that addresses the development. For the construction and the validation of the risk of falling assessment tool in elderly people that live in the community, the procedures proposed by Pasquali (2010) were used, namely: theoretical, empirical and analytical. This study emphasized the theoretical analysis of the items (last part of the theoretical procedures), the empirical an analytical procedures. It should be noted that the construction of EARQUE was carried out in a previous study, however, in this study it went through a refinement before proceeding with the theoretical analysis. The theoretical analysis involves two moments. In the first one, in the face and content validity analysis some judges were chosen, in other words experts from the elderly health field and of the relevant method, that established if the items were related or not to the construct \"risk of falling in elderly people\". In the second, regarding the semantic analysis, the Scale was applied on 20 elderly people selected for convenience with the aim of verifying if all of the items were comprehensible by them. In the empirical procedure a Diagnostic and Screening Test Validation study was carried out. The sample of this stage was composed by 854 elderly people selected by a stratified random sampling procedure with a proportional distribution. Besides the EARQUE pilot version, the QuickScreen® instrument was applied - considering the \"gold-standard\" in this study. The elderly people were divided in two groups (I and II) according to the gold-standard test results and to the QuickScreen® and distributed as follows: elderly people that scored from 0 to 3 risk factors were allocated to the Group I (control group) and those who scored 4 or more than 4 were allocated to the Group II (risk group (cases). With the aim of characterizing the sample, descriptive analyses were realized using measures of central tendency (mean and median), of variability (standard deviation) and of frequency distribution. In order to verify differences of proportions between the EARQUE items and the groups obtained starting from the QuickScreen® application the chi-square test was used (X2). As a measure having an equivalent effect the ratio of prevalence (RP) with its respective Confidence Interval at 95% (IC95%) was used. The significant associations were considered those which showed p values0,05. The third stage consisted in the realization of multivariate logistic regression analyses, with the aim of identifying the association between the EARQUE various items and the higher falling risk in elderly people. Therefore, initially all the EARQUE variables were included in the multivariate analysis and with their association to the QuickScreen® items (p0,05) they were selected for new multivariate analyses and consequently those which showed p values<0,05 remained in the final model of the scale. Finally, for the EARQUE validity evaluation precision measurement were used: sensitivity, specificity, positive predictive value and negative predictive value. Concerning the representation of the sensitivity and the specificity values and for the identification of the best cut-off point, the ROC curve (Receiver Operating Characteristic) was used. The data were organized in Excel and analyzed in the Med Calc statistic software version 16.4.1. For all the analyses realized a significance level of 5% was considered. At the end of the theoretical procedures, EARQUE had 44 items. Regarding the socio-demographic characteristics, the majority of the elderly people were female (492; 57,6%) with an average age of 71,87 years. After comparative analyses between the groups, 27 items were inserted in the regression model. Finally, the multivariate logistic regression analyses showed that only 10 EARQUE items contribute for the increase of risk of falling in elderly people and these are referred to the following risk factors: previous falls, use of a walking aid device, polypharmacy, use of psychotropic substances, difficulty to ascend and descend a slope, difficulty to walk for a distance of 100 meters, visual and auditory deficit, a low physical activity and a badly illuminated environment. This stratification model of risk assumes sensitivity values of 91,3% and specificity values of 73,4%. EARQUE is defined as a valid, simple, low-cost and of easy and rapid application instrument, and it can be used by all the primary health care professionals, including by community health agents, which represents an unpublished contribution. Therefore, this tool discriminates elderly people with higher or lower risk of falling and it will be able to initiate a more comprehensive and detailed evaluation, according to the risk classification - from 0 to 2 points: low risk of falling; 3 points: moderate risk of falling and 4 or more than 4: high risk of falling.

Chan Cheung Shing. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 88-90). / Abstracts in English and Chinese. / Abstract --- p.ii / Acknowledgements --- p.iv / Table of Contents --- p.v / List of Figures --- p.viii / List of Tables --- p.xii / Abbreviations and Notations --- p.xiii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Background and Objective --- p.1 / Chapter 1.2 --- Contribution --- p.4 / Chapter 1.3 --- Thesis Outline --- p.5 / Chapter Chapter 2 --- System Architecture --- p.6 / Chapter 2.1 --- Conceptual Design --- p.6 / Chapter 2.2 --- Sensing Device and Fall-Detection Algorithm --- p.7 / Chapter 2.3 --- Mechanical Part --- p.10 / Chapter Chapter 3 --- Mechanical Design --- p.11 / Chapter 3.1 --- Similar Products --- p.11 / Chapter 3.1.1 --- Airbag Restraining Systems in Automobiles --- p.11 / Chapter 3.1.2 --- Airbag Jackets for Motorcycle and House Riders --- p.12 / Chapter 3.2 --- Mechanism adopted --- p.12 / Chapter 3.2.1 --- Time Requirement of Inflator --- p.12 / Chapter 3.2.2 --- Mechanism and Design --- p.13 / Chapter 3.2.3 --- Actuator --- p.14 / Chapter 3.2.4 --- Punch --- p.15 / Chapter 3.2.5 --- Airbags --- p.18 / Chapter 3.2.6 --- Other Mechanisms Tried --- p.19 / Chapter 3.3 --- Prototype --- p.21 / Chapter 3.3.1 --- Implementation --- p.21 / Chapter 3.3.2 --- Demonstration --- p.23 / Chapter Chapter 4 --- Inflation Estimation --- p.25 / Chapter 4.1 --- Theory and Model --- p.25 / Chapter 4.2 --- Validation of Model --- p.28 / Chapter 4.2.1 --- Testing Equipment --- p.28 / Chapter 4.2.2 --- Preprocessing of Pressure Sensor Outputs --- p.28 / Chapter 4.2.3 --- Validation for Basic Equations --- p.29 / Chapter 4.2.4 --- Adjustment of Discharge Coefficients --- p.36 / Chapter 4.2.5 --- Validation for Discharging to a Fixed Volume --- p.40 / Chapter 4.2.6 --- Estimation of the Size of Airbag's Leakage Hole --- p.45 / Chapter 4.2.7 --- Validation for Discharging to an Airbag --- p.47 / Chapter 4.2.8 --- Time Delay due to Addition of a Pipe --- p.52 / Chapter 4.3 --- Summary of Experiments --- p.53 / Chapter 4.4 --- Limitation of Model --- p.54 / Chapter 4.5 --- Prediction of Inflation Time and Airbag Pressure --- p.55 / Chapter 4.5.1 --- Effects of Orifice Size and Vent Size on Airbag Pressure and Volume --- p.55 / Chapter Chapter 5 --- Force Attenuation Estimation --- p.58 / Chapter 5.1 --- Theory and Model --- p.58 / Chapter 5.1.1 --- Kelvin-Voigt Model --- p.59 / Chapter 5.1.2 --- Standard Linear Solid Support Model --- p.59 / Chapter 5.2 --- Simple Testing for Validation --- p.61 / Chapter 5.3 --- Summary of Experiment --- p.64 / Chapter 5.4 --- Estimation --- p.64 / Chapter 5.4.1 --- Force Attenuation Ability of Prototype --- p.64 / Chapter 5.4.2 --- Minimum Airbag Volume and Pressure Required to Reduce the Force --- p.65 / Chapter Chapter 6 --- Future Work --- p.66 / Chapter 6.1 --- Impact Test for Airbag System --- p.66 / Chapter 6.2 --- The Effective Mass of the Target User --- p.67 / Chapter 6.3 --- The Motion Data Collection --- p.68 / Chapter 6.4 --- Modification in the Inflator --- p.69 / Chapter Chapter 7 --- Conclusion --- p.70 / Appendix A Review of Basic Thermodynamics and Fluid Dynamics --- p.72 / Chapter A.1 --- Thermodynamics --- p.72 / Chapter A.2 --- Fluid Mechanics: Incompressible and Compressible Flow --- p.75 / Appendix B Derivation of Equations --- p.77 / Chapter B.1 --- Mass Flow Rate Equations --- p.77 / Chapter B.2 --- Relationship between Rate of Changes of Airbag Pressure and Volume --- p.80 / Chapter B.3 --- Pressure Change of Compressed Gas Cylinder --- p.82 / Chapter B.4 --- Dominating Factors in the Mass Flow Rate Equation --- p.83 / Appendix C Dimensions of Inflator --- p.85 / Appendix D Experimental Data --- p.86

Introdução: A presença de doença crônica e de várias comorbidades, somados à mobilidade reduzida e fraqueza muscular são fatores frequentemente associados ao risco de quedas em idosos, sendo o dano do equilíbrio um dos mais importantes preditores de quedas. Atualmente, há uma crescente evidência de que pacientes com Doença Pulmonar Obstrutiva Crônica (DPOC) são bastante suscetíveis a quedas visto que têm apresentado importantes déficits de equilíbrio. Há alguns estudos que avaliam o papel de fatores isolados deste déficit, contudo, a avaliação de múltiplos fatores na mesma população de pacientes ainda não foi muito investigada, assim como o impacto desta alteração de equilíbrio na predição de quedas nesta população ainda é pouco conhecido. Objetivos: Determinar que fatores estão associados à alteração de equilíbrio postural em pacientes com DPOC e avaliar o impacto desta alteração do equilíbrio na predição de quedas nesta população. Métodos: Este estudo prospectivo de coorte incluiu 70 pacientes ambulatoriais com diagnóstico prévio de DPOC. Para a avaliação do equilíbrio os pacientes foram submetidos ao Mini-BESTest (Balance Evaluation Systems Test). As variáveis sexo, idade, frequência de exacerbações / hospitalizações decorrentes da doença respiratória no último ano foram coletados a partir de entrevista pessoal e de registros clínicos. A presença de comorbidades foi avaliada por meio da aplicação de uma escala denominada Functional Comorbidity Index (FCI). O nível de atividade física foi mensurado por meio de um sensor de movimento (acelerômetro), a força isométrica muscular máxima de membros inferiores foi avaliada por um dinamômetro, a qualidade do sono mensurada por meio do questionário Pittsburgh Sleep Quality Index, a dispneia pela modified Medical Research Council (mMRC) dyspnoea scale, o medo de quedas pela escala Falls Efficacy Scale-International (FES-I) e a função pulmonar por meio da prova de função pulmonar completa. Além disso, a incidência de quedas nos pacientes foi seguida por um ano sendo avaliada mensalmente por um diário de autorrelato de quedas, entregue ao paciente após a avaliação inicial, e confirmada por ligações telefônicas. Para a análise estatística foram utilizados modelos de análise de regressão e análise de poder discriminativo através da Receiver operator characteristic curve (ROC curve). O nível de significância foi ajustado para todas as análises e foi de 5% (p < 0,05). Resultados: Verificou-se que o equilíbrio postural (Mini-BESTest - pontuação total) esteve independentemente associado à força muscular de quadríceps, ao medo de queda (FES-I) e à idade, ajustados pela inatividade física (p < 0,001, r2 ajustado=0,49). Ao analisar cada domínio correspondente a um sistema do controle postural separadamente pudemos verificar também que o equilíbrio postural esteve independentemente associado a: idade e inatividade física, ajustados pelo índice de massa corpórea (IMC) no domínio \"Ajustes Posturais Antecipatórios\" (p=0,001, r2 ajustado=0,22); idade, força muscular de quadríceps e pressão inspiratória máxima (PImáx), ajustados pelo aprisionamento aéreo no domínio \"Respostas Posturais Reativas\" (p < 0,001, r2 ajustado=0,47); medo de queda e força muscular de dorsiflexores de tornozelo no domínio \"Orientação Sensorial\" (p=0,001, r2 ajustado=0,16); e qualidade do sono, inatividade física, idade e força muscular de plantiflexores de tornozelo no domínio \"Estabilidade na marcha\" (p < 0,001, r2 ajustado=0,24). Além disso, 37,3% dos pacientes apresentaram pelo menos um evento de queda em um período de 12 meses de seguimento. Verificou-se também que um melhor desempenho no controle postural, avaliado pelo Mini-BESTest esteve associado a um menor risco de queda [Odds ratio (OR)=0,50] e que o Mini-BESTest mostrou ser um bom instrumento para predizer quedas futuras em pacientes com DPOC [Area under the curve (AUC)=0,87, sensibilidade=84% e especificidade=73,8%]. Conclusões: A alteração do equilíbrio postural nesta população de pacientes com DPOC está associada à idade, fraqueza muscular de membros inferiores, medo de queda, qualidade do sono, inatividade física e à função pulmonar. Além disso, a alteração no equilíbrio postural é um bom preditor de quedas futuras nesta população, sendo o Mini-BESTest um bom instrumento para identificar os pacientes com maior risco de quedas. A implementação de programas de reabilitação que incluam treinamento de equilíbrio específico e prevenção de queda pode ser necessária para estes pacientes / Introduction: The presence of chronic disease and several comorbidities, added to reduced mobility and muscle weakness are often associated with the risk of falls in the elderly, with balance impairment being one of the most important predictors of falls. Currently, there is growing evidence that patients with chronic obstructive pulmonary disease (COPD) are quite susceptible to falls since they have presented significant balance deficits. There are some studies that evaluate the role of isolated factors in this deficit, however, the evaluation of multiple factors in the same sample of patients has not yet been much investigated, as well as the impact of this balance impairment in the prediction of falls in this population is not clear in the literature. Objectives: To determine the factors that are associated with postural balance impairment in patients with COPD and to evaluate the impact of this impairment on the prediction of falls in this population. Methods: This prospective cohort study included 70 outpatients with a previous diagnosis of COPD. Postural balance was evaluated by the Mini-BESTest (Balance evaluation systems test). Gender, age, frequency of exacerbations / hospitalizations resulting from respiratory disease in the last year were collected from an initial interview and patients\' medical records. The presence of comorbidities was evaluated using the scale of Functional Comorbidity Index (FCI). The level of physical activity was measured using a motion sensor (accelerometer type), the maximal isometric muscle strength of the lower limbs was assessed using a dynamometer, the sleep quality measured by the Pittsburgh Sleep Quality Index, the dyspnea by the modified Medical Research Council (mMRC) dyspnoea scale, the fear of falling by the Falls Efficacy Scale-International scale (FES-I) and the lung function obtained by the Complete Pulmonary Function Test. In addition, the incidence of falls was followed for one year, assessed monthly by a calendar of self-reports of falls, given to the patient after the initial assessment, and confirmed by telephone calls. For the statistical analysis, regression analyses models and discriminative power analysis by receiver operator characteristic curve (ROC) were used. The level of significance was adjusted for all analyses and was 5% (p < 0.05). Results: Postural balance (Mini-BESTest) was independently associated with quadriceps muscle strength, fear of falling (FES-I) and age, adjusted for physical inactivity (p < 0.001, adjusted r2=0.49). When analyzing each domain corresponding to a postural control system separately, we could also verify that the postural balance was independently associated with: age and physical inactivity, adjusted by the body mass index (BMI) in the domain \"Postural Anticipatory Adjustments\" (p=0.001, adjusted r2=0.22); age, quadriceps muscle strength and maximal inspiratory pressure (MIP), adjusted by air trapping in the \"Postural Reactive Responses\" domain (p < 0.001, adjusted r2=0.47); fear of falling and ankle dorsiflexors muscle strength in the domain \"Sensory Orientation\" (p=0.001, adjusted r2=0.16); and sleep quality, physical inactivity, age and ankle plantiflexors muscle strength in the domain \"Balance during gait\" (p < 0.001, adjusted r2=0.24). In addition, 37.3% of patients had at least one fall event over a 12-month follow-up period. It was also verified that a better performance in postural control evaluated by Mini-BESTest was associated with a lower risk of fall [Odds ratio (OR) = 0.50] and that Mini-BESTest was showed to be a good tool to predict future falls in patients with COPD [Area under the curve (AUC)= 0.87, sensitivity = 84% and specificity = 73.8%]. Conclusions: Postural balance impairment in patients with COPD is associated with age, lower limb muscle weakness, fear of falling, sleep quality, physical inactivity and lung function. In addition, the postural balance impairment is a good predictor of future falls in this population, and Mini-BESTest is a good tool to identify patients at greater risk of falls. The implementation of rehabilitation programs that include specific balance training and fall prevention may be required for these patients

Falls and concomitant injuries are common problems among large groups of the elderly population, leading to immobility and mortality. These problems are even more pronounced among people suffering from dementia. This thesis targets fall risk factors for people with dementia in institutions. The overall aim of this thesis was to investigate risk factors for falls, predisposing as well as related to circumstances surrounding falls, and to do this as efficiently as possible. In a prospective cohort study including residents of residential care facilities with and without dementia, the fall rate was higher for those with dementia, the crude incidence rate ratio (IRR) was 2.55 (95% CI 1.60–4.08) and the adjusted IRR was 3.79 (95% CI 1.95–7.36). In the group of people suffering from dementia, including 103 residents, a total of 197 falls resulted in 11 fractures during the 6-months follow-up period. From the same baseline measurements 26% and 55%, respectively, of the variation in falls could be explained in the group of residents with and without dementia. Fall predictors significantly and independently associated with an increased risk of falls in the group of people suffering from dementia were the category “man walking with an aid” and the use of more than four drugs. In a prospective cohort study, including 204 patients in a psychogeriatric ward, a total of 244 falls resulted in 14 fractures. Fall predictors significantly and independently associated with an increased risk of falls were male sex, failure to copy a design, use of clomethiazole, and walking difficulties. Treatment with statins was associated with a reduced risk of falls. With these fall predictors in the negative binomial regression (Nbreg) model, 48% of the variation in falls was explained. The data from the psychogeriatric ward were also analysed with the use of partial least squares regression (PLS) and regression tree to be compared with the results of the Nbreg analysis. PLS and regression tree are techniques based on combinations of variables. They both showed similar patterns, that a combination of a more severe level of dementia, behavioral complications and medication related to these complications is associated with an increased fall rate. Thirty-two percent and 38%, respectively, of the variation in fall rate were explained in the PLS and regression tree analysis. The circumstances surrounding the falls in the psychogeriatric ward were analysed. It was found that the fall rate was equally high during the night and the day. A large proportion of the falls was sustained in the patients’ own room and a small proportion of the falls was witnessed by the staff. This pattern was even more pronounced during the night. The proportion of diurnal rhythm disturbances and activity disturbances was higher for falls at night than for falls during the day. Circumstances associated with an increased risk of falls, as shown by a short time to first fall, were anxiety, darkness, not wearing any shoes and, for women, urinary tract infection. The proportion of urinary tract infection was also higher in connection to falls sustained by women than to falls sustained by men. This thesis confirms that people suffering from dementia are prone to fall. Walking difficulties, male sex and impaired visual perception are factors that should be considered in the work of reducing falls among people suffering from dementia. Furthermore, falls at night, behavioral complications and medication related to these complications should also be considered in this work, especially as the dementia disease progresses. A larger portion of the variation of the outcome variable was explained by the Nbreg model than the regression tree and PLS. However, these statistical methods, based on combinations of variables, gave a complementary perspective on how the fall predictors were related to falls.

The number of old people is growing and will increase future demands on healthcare services for old people. Hip fracture is one of the diagnoses that increases with age and it has become a major problem, both for those suffering a fracture and for society due to the large numbers involved, the morbidity with complications such as falls, functional decline, and the high mortality rate among those affected. The main purposes of this thesis were, to study the impact of previous hip fractures on their life among the very old, to study in-patient falls, fall-related injuries and fall-risk factors, and to evaluate a multidisciplinary, multi-factorial intervention program designed to reduce in-patient falls and to enhance functional performance among old people who have sustained a femoral neck fracture. The impact of a hip fracture was examined in a cross-sectional population-based study, among the very old (Umeå 85+). After adjustment for potential covariates, participants with a history of hip fracture were found to be more dependent in the performance of Personal/Primary Activities of Daily Living (P-ADL) (p=0.024), walked less independently (p=0.040) and used a wheelchair more frequently (p=0.017). Most of the participants with earlier hip fractures who had moved to institutional care or begun using mobility aids, as compared to before the fracture, had started to do so permanently in connection with the fracture incident. In-patient falls, fall-related injuries and fall-risk factors were studied in 97 participants, aged 70 or more, treated for a femoral neck fracture. There were 60 postoperative falls occurring among 26/97 participants (27%). Thirty-two percent of the falls resulted in injuries, 25 % were minor, and 7 % were serious. Delirium after day seven, (Hazard Rate Ratio (HRR) with a 95% Confidence Interval (CI)), 4.62 (1.30-16.37), male sex 3.92 (1.58-9.73), and sleeping disturbances 3.49 (1.24-9.86), were associated with in-patient falls. Forty-five percent of the participants were delirious on the day they fell. The effects of a multidisciplinary, multi-factorial intervention program on in-hospital falls and injuries as well as the short- and long-term effects on living conditions, walking ability and performance of activities of daily living were evaluated in a randomised controlled trial among 199 participants with femoral neck fracture, aged ≥70 years. Participants were randomised to care in a geriatric ward (intervention, n=102) or to conventional postoperative routines (control, n=97). The intervention consisted of staff education, individualized care planning and rehabilitation, systematic assessment and treatment of fall-risk factors, active prevention, and detection and treatment of postoperative complications and an intervention follow up at four-months. The staff worked in teams to apply comprehensive geriatric assessment, management and rehabilitation. Twelve participants fell a total 18 times in the intervention group compared to 26 participants suffering a total 60 falls in the control group. Only one participant with dementia fell in the intervention group compared to 11 participants with dementia in the control group. The fall incidence rate was 6.29/1000 days vs. 16.28/1000 for the intervention and control groups respectively. The Incidence Rate Ratio (IRR) was 0.38 (95% CI: 0.20-0.76, p=0.006) for the total sample and 0.07 (95% CI: 0.01-0.57, p=0.013) among participants with dementia. No new fractures were incurred in the intervention group but there were four in the control group. In addition, despite shorter hospitalization, significantly more people from the intervention group had regained independence in P-ADL performance at the four- and twelve-month follow ups, Odds Ratios (OR), with 95% CI, were 2.51 (1.00-6.30) and 3.49 (1.31-9.23) respectively. More participants in the intervention group had also regained the ability to walk independently without walking aids indoors, at the end of the study period, 3.01 (1.18-7.61). In conclusion, hip fracture among the very old seems to be associated with poorer P-ADL performance and poorer mobility. Falls and injuries are common during in-patient rehabilitation after a femoral neck fracture, delirium and sleep disturbances and male gender are factors associated with in-patient falls. Having a team apply comprehensive geriatric assessments and rehabilitation, including the prevention, detection and treatment of fall-risk factors, can successfully prevent in-patient falls and fall-related injuries, even among participants with dementia, and can also enhance the performance of Activities of Daily Living (ADL) and mobility after a hip fracture, in both short- and long-term perspectives.

The very old, aged 80 years and over, is the fastest growing age group today, and the demands for healthcare and services will be even higher in the future. It is, therefore, of great importance to advance our knowledge about this group. The main purpose of this thesis was to describe living conditions and health, with a special focus on physical ability, falls and morale, in women and men in three different age groups of very old people in northern Sweden. Half the population aged 85, and the total population aged 90 and ≥95 (-103) in the municipality of Umeå were selected for participation (n=348) in this population-based cross-sectional study, entitled the Umeå 85+ Study. Structured interviews and assessments were performed with the participants in their homes, and data were also collected from next-of-kins, caregivers and medical charts. Cognition was screened for using the Mini-Mental State Examination (MMSE), depressive symptoms using the Geriatric Depression Scale-15 (GDS-15), and nutritional status using the Mini Nutritional Assessment (MNA). Activities of Daily Living (ADL) were assessed using the Staircase of ADL (including the Katz Index of ADL) and morale using the Philadelphia Geriatric Center Morale Scale (PGCMS). Participants also rated their own health and answered a questionnaire about symptoms. Physical ability was assessed using a gait speed test over 2.4 meters (8 feet), three consecutive chair stands, and the Berg Balance Scale (BBS). A follow-up study for falls was performed during a period of six months with fall calendars and telephone calls. The very old people in this northern population have more depression, hypertension and hip fractures, as well as a higher consumption of drugs than comparable, more southern populations. In general, younger participants had lower rates of diagnoses and prescribed drugs, were less dependent in ADL and other functional variables than older participants, and men had lower rates of diagnoses and reported symptoms than women. However, there were no age or sex differences in self-rated health or morale, which were both rated as good by the majority of the participants. There was a wide range of physical ability among these very old people, especially in women, where an age-related decline was seen. The results also demonstrate that men had greater physical ability than women. The BBS had no floor or ceiling effects in the present sample. In contrast, a large proportion was unable to perform the gait speed and chair stands test, resulting in a floor effect for the timed performances, especially in women. Falling is a major public health problem in very old people. From the results of the present study, it could be predicted that every seventh participant and every third of the people who did fall would suffer a fracture over a period of one year. The independent explanatory risk factors for time to first fall in this sample of very old people were dependency in personal (P-) ADL but not bedridden, thyroid disorders, treatment with Selective Serotonin Reuptake Inhibitors (SSRIs) and occurrence of fall/s in the preceding year. These factors should all be considered in fall prevention programmes. The morale of very old people was found in this study to be rather high, with similar scores among age groups and sexes. The most important factors for high morale were the absence of depressive symptoms, living in ordinary housing, having previously had a stroke and yet still living in ordinary housing, not feeling lonely and having few symptoms. The PGCMS seems applicable in the evaluation of morale in very old people. In conclusion, there were wide variations in health status and physical ability in this northern population of very old people. Women had poorer health and physical ability than men. Falls and fractures were common and serious health problems. Morale seemed to be high, despite the fact that a large proportion of the participants suffered from many diseases and functional decline.

Impairments in balance, mobility, and lower-limb strength are common in the growing population of older people and can lead to dramatic consequences for the individual, such as dependency in activities of daily living, admission to nursing home, falls, and fractures. The main purposes of this thesis were, among older people in residential care facilities, to validate a fall-risk assessment tool and to evaluate a high-intensity functional weight-bearing exercise pro-gramme regarding its applicability as well as its effect on physical functions and falls. The prediction accuracy of the Downton fall risk index within 3, 6 and 12 months was evaluated among 78 residents, aged 65 years or more, at one residential care facility. The participants were assessed as having either a low or high fall risk according to the index and were followed-up for falls using two different fall definitions related to the cause of the fall. With all falls included, a significant prognostic separation was found between the low- and the high-risk group at 3, 6 and 12 months. A definition in which falls precipitated by acute illness, acute disease, or drug side-effects were excluded did not improve the accuracy of the fall prediction. The effect on physical functions of a high-intensity functional exercise programme was evaluated in a randomised controlled trial among 191 older people, dependent in activities of daily living, with a Mini-Mental State Examination score of ten or more, and living in nine residential care facilities. Participants were randomised to an exercise programme or a control activity, including 29 supervised sessions over 3 months, as well as to an intake of a milk-based 200 ml protein-enriched energy supplement (7.4 g protein per 100 g) or a placebo drink immediately after each session. The Berg Balance Scale, usual and maximum gait speed, and one-repetition maximum in lower-limb strength in a leg press machine were followed up at 3 and 6 months by blinded assessors and analysed using the intention-to-treat principle. Significant long-term effects of the high-intensity functional exercise programme were seen in balance, gait ability and lower-limb strength in comparison with the control activity. The intake of the protein-enriched energy supplement did not increase the effect of the training. The evaluation of the applicability of the exercise programme showed that there was a high rate of attendance, a relatively high achieved intensity in the exercises, and only two serious adverse events, neither of which led to manifest injury or disease, despite that most of the participants had severe cognitive or physical impairments. The applicability of the programme was not associated with the participants’ cognitive function. The evaluation of the fall-prevention effect of the exercise programme, during the 6 months following the intervention, showed that neither fall rate nor proportion of participants who sustained a fall differed between the exercise programme and the control activity, when all participants were compared. However, among participants who improved their balance during the intervention period, a significant reduction in fall rate was seen in favour of the exercise group. In conclusion, among older people living in residential care facilities, the Downton fall risk index appears to be a useful tool for predicting residents sustaining a fall, irrespective of the cause of the fall, even with a perspective of only a few months. A high-intensity functional exercise programme is applicable for use, regardless of cognitive function, and has positive long-term effects on balance, gait ability, and lower-limb strength. An intake of a protein-enriched energy supplement immediately after the exercise does not appear to increase the effect of the training. Participants who improve their balance function due to the exercise programme may reduce their risk of falling.

Many epidemiological studies assess the effects of time-dependent exposures, where both the exposure status and its intensity vary over time. The analysis of such studies poses the challenge of modelling the association between complex time-dependent drug exposure and the risk, especially given the uncertainty about the etiological relevance of doses taken in different time periods. / To address this challenge, I developed a flexible method for modelling cumulative effects of time-varying exposures, weighted by recency, represented by time-dependent covariates in the Cox proportional hazards model. The function that assigns weights to doses taken in the past is estimated using cubic regression splines. Models with different number of knots and constraints are estimated. Bootstrap techniques are used to obtain pointwise confidence bands around the weight functions, accounting for both the sampling variation of the regression coefficients, and the uncertainty at the model selection stage, i.e. the additional variance due to a posteriori selection of the number of knots. / To assess the method in simulations, I had to develop and validate a novel algorithm to generate event times conditional on time-dependent covariates and compared it with the algorithms available in the literature. The proposed algorithm extends a previously proposed permutational algorithm to include a rejection sampler. While all the algorithms generated data sets that, once analyzed, provided virtually unbiased estimates with comparable variances, the algorithm that I proposed reduced the computational time by more than 50 per cent relative to alternative methods. I used simulations to systematically investigate the properties of the weighted cumulative dose method. Six different weight functions were considered. Simulations showed that in most situations, the proposed method was able to capture the shape of the true weight functions and to produce estimates of the magnitude of the exposure effect on the risk that were close to those used to generate the data. I finally illustrated the use of the weighted cumulative dose modelling by reassessing the association between the use of selected benzodiazepines and fall-related injuries, using administrative data on a cohort of elderly who initiated their use of benzodiazepines between 1990 and 2004.

People aged ≥65 years (older people) have a higher chance of falling than other age groups. However, based on qualitative research, older people do not believe that falls prevention information and strategies have personal relevance. This suggests that older people believe that falls are more likely to happen to other older people than themselves, that is, they might be comparatively optimistic about their chance of falling. It is important to understand comparative optimism about falling as it is a consistent reason given by older people for not participating in falls prevention activity. This thesis used a mixed methods design with a sequential strategy to investigate community-dwelling older people's comparative optimism about falling. Three studies were undertaken, using semi-structured interviews, cognitive interviews and telephone interviews to collect data. The semi-structured interview study, guided by the tenets of grounded theory, aimed to develop an explanation of why older people might be comparatively optimistic. A sampling frame (age, sex and direct and indirect history of falling) was used to guide recruiting respondents. Older people (N = 9) were interviewed about their chance and other older people's chance of falling. Interviews were analysed using the constant comparison method. The cognitive interview study investigated potential problems in survey items in order to refine them for the telephone interview study. Items were developed to measure older people's comparative optimism about falling. Older people (N = 13) were cognitively interviewed, and interviews were content analysed. The telephone interview study aimed to determine whether older people were comparatively optimistic about falling, and whether the direct and indirect experience of falling was associated with comparative optimism. A random sample of older people (N = 389) living in South Australia were telephone interviewed (response rate = 75%). The semi-structured interview study identified that it was a 'threat to identity' for respondents to say they had a chance of falling because of intrinsic risk factors. Respondents used strategies to maintain or protect their identity when discussing their chance of falling in the future or their reasons for falling in the past. In the cognitive interview study, respondents reported difficulty in rating their chance of falling, as they believed falls were unexpected and unpredictable. They reported difficulty in rating other people's chance of falling, as they believed they did not know other people their age, did not have enough information and/or did not know the answer. In the telephone interview study, most respondents believed they had the same chance (42%), or a lower chance (48%) of falling in the next 12 months, than other older people. Having fallen in the last 12 months was significantly associated with a lowered comparative optimism, but knowing other older people who had fallen was not associated with comparative optimism. This is the first quantitative study to report that the majority of a representative sample of community-dwelling older people were comparatively optimistic about their chance of falling. Self-presentation concerns about having a chance of falling support the core category to emerge from the semi-structured interview study. Messages such as 'you can reduce your risk of falls' may be ignored by older people. Alternative messages should promote identities that are relevant to older people, such as being independent, mobile and active, but these messages should be tested in further research. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1374964 / Thesis (Ph.D.) - University of Adelaide, School of Psychology and School of Population Health and Clinical Practice, 2009