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Background
Multimorbidity in the older population is well acknowledged to negatively affect health-related quality of life (HRQL). Several studies have examined the independent effects of single diseases; however, little research has focused on interaction between diseases. The purpose of this study was to assess the impact of six self-reported major conditions and their combinations on HRQL measured by the EQ-5D.
Methods
The EQ-5D was administered in the population-based KORA-Age study of 4,565 Germans aged 65 years or older. A generalised additive regression model was used to assess the effects of chronic conditions on HRQL and to account for the nonlinear associations with age and body mass index (BMI). Disease interactions were identified by a forward variable selection method.
Results
The conditions with the greatest negative impact on the EQ-5D index were the history of a stroke (regression coefficient -11.3, p < 0.0001) and chronic bronchitis (regression coefficient -8.1, p < 0.0001). Patients with both diabetes and coronary disorders showed more impaired HRQL than could be expected from their separate effects (coefficient of interaction term -8.1, p < 0.0001). A synergistic effect on HRQL was also found for the combination of coronary disorders and stroke. The effect of BMI on the mean EQ-5D index was inverse U-shaped with a maximum at around 24.8 kg/m2.
Conclusions
There are important interactions between coronary problems, diabetes mellitus, and the history of a stroke that negatively affect HRQL in the older German population. Not only high but also low BMI is associated with impairments in health status.
Background
Multimorbidity in the older population is well acknowledged to negatively affect health-related quality of life (HRQL). Several studies have examined the independent effects of single diseases; however, little research has focused on interaction between diseases. The purpose of this study was to assess the impact of six self-reported major conditions and their combinations on HRQL measured by the EQ-5D.
Methods
The EQ-5D was administered in the population-based KORA-Age study of 4,565 Germans aged 65 years or older. A generalised additive regression model was used to assess the effects of chronic conditions on HRQL and to account for the nonlinear associations with age and body mass index (BMI). Disease interactions were identified by a forward variable selection method.
Results
The conditions with the greatest negative impact on the EQ-5D index were the history of a stroke (regression coefficient -11.3, p < 0.0001) and chronic bronchitis (regression coefficient -8.1, p < 0.0001). Patients with both diabetes and coronary disorders showed more impaired HRQL than could be expected from their separate effects (coefficient of interaction term -8.1, p < 0.0001). A synergistic effect on HRQL was also found for the combination of coronary disorders and stroke. The effect of BMI on the mean EQ-5D index was inverse U-shaped with a maximum at around 24.8 kg/m2.
Conclusions
There are important interactions between coronary problems, diabetes mellitus, and the history of a stroke that negatively affect HRQL in the older German population. Not only high but also low BMI is associated with impairments in health status.
Within the scope of the recently finished cooperate research project "VibWood" at Technical University of Munich and Rosenheim University of Applied Sciences, fully parametrized numerical models for lightweight wooden floor constructions have been developed and calibrated by experimental modal analyses.
Based on a vast parametric study including floating floors and suspended ceilings a database of narrowband sound power levels in the frequency range up to 125 Hz for a wide range of floor dimensions has been set up.
A procedure will be presented on how to process the numerical data and derive single number values that allow a comparison to the standardized rating of impact sound insulation according to DIN EN ISO 717-2.
The derived data is implemented into a graphical user interface (GUI). This GUI is available for free. The database is open for additional geometries and will be enhanced by different constructions in the near future.
Objectives
The objective of this study was to assess the objectivity, cross-cultural validity, and convergent validity of the Vestibular Activities and Participation (VAP) questionnaire among four countries, Germany, United States, Jordan, and Saudi Arabia.
Study Design and Setting
This was a cross-sectional study conducted in four specialized outpatient dizziness clinics in Germany, United States, Jordan, and Saudi Arabia.
Results
A total of 453 participants were included in the study. The Rasch analysis revealed two separate subscales. Subscale 1 items included focusing attention, lying down, standing, bending, lifting and carrying objects, and sports. Subscale 2 items included walking long distances, climbing, running, moving around within buildings other than home, using transportation, and driving. The Pearson product–moment correlation between the Dizziness Handicap Inventory and the summary score of the VAP subscale 1 was 0.66 and was 0.64 for subscale 2.
Conclusion
Owing to its shortness and intercultural adaptability, the new two-scale version of the VAP questionnaire lends itself to clinical practice and research across countries to estimate the effect of vertigo and dizziness on activity limitation and participation restrictions. Psychometrically sound summary scores can be calculated. More extended versions of the VAP can be used for comprehensive clinical assessment where summary scores are not needed or a more detailed documentation is warranted.
In this contribution a method for the prediction of the radiated sound out of the velocity field of a vibrating ceiling is presented. The numerical method was validated via measurements on a real structure using a pp-probe. It is based on Integral Transform techniques and can be applied in the postprocessing of a FEM simulation
(harmonic analysis) [1]. The method was verified by measurements on the real structure and can be used for parametrical studies.
Rounding off the Parts 1 and 2 of this publication nomograms, based on dimensionless parameters, can be developed to predict the sound radiation of light weight slabs. Hereby different sets of geometry as well as different configurations of ceilings can be studied in order to describe the acoustical and dynamical behaviour of wooden ceilings.
In order to set up guidelines for the design of light-weighted ceilings for timber constructions to be used by engineers in practice, investigations based on both measurements and numerical models have been carried out [1, 2, 3].
The setup and the calibration of the numerical model of the structure are outlined briefly.
A semi-analytical approach for the prediction of radiated sound is presented, which is based on Integral Transform Methods. The method can be applied in the post processing of a Finite Element computation.
Thus as a first step the structure, consisting of a timber slab, a floating floor and a suspended ceiling, is built up in a Finite Element model, where the material properties of wood and the characteristics of the system are considered.
The model is parameterized in order to enable computations with varying geometry and material parameters and calibrated with the help of measurements using model updating techniques.
The velocity pattern resulting out of the FEM computation is transformed from the spatial into the wavenumber domain and from the time into the frequency domain using Fourier Transform Methods. Applying this velocity pattern as a boundary condition to the Helmholtz Equation, which results out of the Fourier Transform of the wave equation, the wavenumbers, which fulfil the radiation condition, can be selected and the pressure field in the adjacent acoustic fluid can be computed.
Due to the properties of the Fourier-Transform the radiated sound power can be calculated efficiently in the transformed domain out of pressure and velocity.
In a second part of the contribution the model for the air cushion in the suspended ceiling is discussed, where a FSI-model for the acoustic fluid and the structure is compared against engineering approaches using simplifications concerning mass distribution and transfer impedances between the individual nodes at the interface
Numerical models for the prediction of vibroacoustical characteristics of light-weighted ceilings
(2013)
In order to set up guidelines for the design of light-weighted ceilings for timber constructions to be used by engineers in practice, investigations based on both measurements and numerical models have been carried out within the cooperative research project “VibWood”.
In this contribution the setup and the calibration of the numerical model of the structure as well as the prediction of radiated sound are discussed, where a special focus is set on a dimensionless description in order to deduce information for a wide range of system’s specifications.
The structure, consisting of a timber slab, a floating floor and a suspended ceiling, is built up in a Finite Element model, where the material properties of wood and the characteristics of the system (e.g.support conditions, contact phenomena dynamic properties of individual parts) are considered.
The model is parameterized in order to enable computations with varying geometry and material parameters.
After calibrating the FE-model with the help of measurements using model updating techniques dimensionless parameters are defined based on the Buckingham-π- Theorem and computations are carried out in order to specify guidelines for various systems. The radiation of sound is computed in a post processing using Integral Transform Methods.
Within the scope of the research project "VibWood", operational vibration analyses of timber floor constructions were carried out. In order to understand the vibration behaviour of and the sound transmission through the layers of the constructions the coupling between them was investigated. The transfer function from the point of excitation to a pattern of receiving positions located on each of the layers of the construction was measured using a swept sine excitation. As a result, the frequency range of decoupling between the base floor and the floating floor and between the base floor and the suspended ceiling could be identified and the individual vibration behavior analyzed. The measurements also included the radiated sound power from the suspended ceiling. There is indication that there is not necessarily a correlation between the eigenmodes of the suspended ceiling and the maxima of the radiated sound power