Dynamic weight-bearing assessment of pain in knee osteoarthritis: a reliability and agreement study

Purpose: To evaluate the reliability, agreement and smallest detectable change in a measurement instrument for pain and function in knee osteoarthritis; the Dynamic weight-bearing Assessment of Pain (DAP). Methods: The sample size was set to 20 persons, recruited from the outpatient osteoarthritis clinic at Frederiksberg Hospital, Copenhagen. Two physiotherapists tested all participants during two visits; at the first visit, one single DAP (including four scores) was conducted by rater one; at the second visit, DAP was conducted by both raters one and two in randomized order with concealed allocation. The time interval was approximately 1.5 h. Measurement error was estimated by standard error of measurement (SEM). The intra- and inter-rater reliability was estimated by Intra-class Correlation Coefficients for agreement based on a two-way ANOVA with random effects (single measures ICC 2.1). Smallest detectable change (SDC) and limits of agreement were calculated.Results: The pain score showed excellent reliability in terms of ICC (intra-rater 0.93, CI 0.83–0.97, inter-rater 0.91, CI 0.78–0.96), low SEM (intra-rater 0.70, inter-rater 0.86, on a scale from 0 to 10), and acceptable SDC for intra-rater test (1.95). The three knee bend scores all had ICC above 0.50, showing fair-to-good reliability. None of the knee bend scores showed acceptable SEM and SDC. Conclusions: The reproducibility of the DAP pain score meets the demands for use in clinical practice and research. The total knee bend could be useful for motivational purpose in clinical use. Testing of other psychometric properties of the DAP is pending.

Characterizing eating patterns: a comparison of eating occasion definitions

BACKGROUND: To date, many approaches have been used to define eating occasions (EOs). A standard definition for EOs is required to facilitate further research. OBJECTIVE: In this study, we examined the influence of differing definitions of EOs on the characterization of eating patterns. DESIGN: Cross-sectional dietary data from two 24-h recalls collected during the 2011-12 Australian National Nutrition and Physical Activity Survey (n = 5242 adults, aged ≥19 y) were analyzed. Eight definitions were applied: participant-identified, time-of-day, and 6 neutral definitions (individual EOs separated by different time intervals and/or an additional energy criterion of 210 kJ). Frequency of and total energy intake from meals, snacks, and all EOs were estimated, as appropriate. Differences were tested by using F tests, stratified by sex and age group. Agreement between different definitions of meal and snack frequencies was assessed by using intraclass correlation coefficients (ICCs). For each definition, linear regression was used to estimate the proportion of variance in total energy intake (kJ) and amount of food intake (g) predicted by frequency of EOs and meals and snacks. RESULTS: Among both sexes and across all age groups, mean frequencies of meals differed between the participant-identified and time-of-day definitions (mean difference range = 0.1-0.3; P < 0.001). There were statistically significant differences between mean frequencies of EOs across the 6 neutral definitions (P < 0.001). There was good agreement for snacks (men: ICC = 0.89; women: ICC = 0.87) but not meal frequencies (men: ICC = 0.38; women: ICC = 0.36) between the participant-identified and time-of-day definitions. The neutral definition (15-min time interval plus energy criterion) best predicted variance in total energy intake (R(2) range = 19.3-27.8). CONCLUSIONS: Different approaches to the definition of EOs affect how eating patterns are characterized, with the neutral definition best predicting variance in total energy intake. Further research that examines how different EO definitions affect associations with health outcomes is needed to develop consensus on a standard EO definition.

Can simple mobile phone applications provide reliable counts of respiratory rates in sick infants and children? An initial evaluation of three new applications

BACKGROUND: Respiratory rate is an important sign that is commonly either not recorded or recorded incorrectly. Mobile phone ownership is increasing even in resource-poor settings. Phone applications may improve the accuracy and ease of counting of respiratory rates. OBJECTIVES: The study assessed the reliability and initial users' impressions of four mobile phone respiratory timer approaches, compared to a 60-second count by the same participants. METHODS: Three mobile applications (applying four different counting approaches plus a standard 60-second count) were created using the Java Mobile Edition and tested on Nokia C1-01 phones. Apart from the 60-second timer application, the others included a counter based on the time for ten breaths, and three based on the time interval between breaths ('Once-per-Breath', in which the user presses for each breath and the application calculates the rate after 10 or 20 breaths, or after 60s). Nursing and physiotherapy students used the applications to count respiratory rates in a set of brief video recordings of children with different respiratory illnesses. Limits of agreement (compared to the same participant's standard 60-second count), intra-class correlation coefficients and standard errors of measurement were calculated to compare the reliability of the four approaches, and a usability questionnaire was completed by the participants. RESULTS: There was considerable variation in the counts, with large components of the variation related to the participants and the videos, as well as the methods. None of the methods was entirely reliable, with no limits of agreement better than -10 to +9 breaths/min. Some of the methods were superior to the others, with ICCs from 0.24 to 0.92. By ICC the Once-per-Breath 60-second count and the Once-per-Breath 20-breath count were the most consistent, better even than the 60-second count by the participants. The 10-breath approaches performed least well. Users' initial impressions were positive, with little difference between the applications found. CONCLUSIONS: This study provides evidence that applications running on simple phones can be used to count respiratory rates in children. The Once-per-Breath methods are the most reliable, outperforming the 60-second count. For children with raised respiratory rates the 20-breath version of the Once-per-Breath method is faster, so it is a more suitable option where health workers are under time pressure.

Structural breaks and unit roots in Australian macroeconomic time series

We examine the unit root properties of 16 Australian macroeconomic time series using monthly data spanning the period 1960–2004. In addition to the standard Augmented Dickey Fuller (ADF) test, we implement one- and two-break endogenous structural break ADF-type unit root tests as well as one- and two-break Lagrange multiplier (LM) unit root tests. While the ADF test provides relatively little evidence against the unit root null hypothesis, once we allow for structural breaks we are able to reject the unit root null for just under half of the variables at the 10% level or better.

Passing time in Clifton Court : an ethnographic study of a unit for confused older people

An exploration of how the residents of a 30 bed unit for confused older people spent their time and a description of the impact upon this of any associated factors. The study demonstrates that it is possible for for elders with dementia and mental health problems to enjoy a range of activities, however, these need to be individualised to take into account the skills they have to meet the challenges with which they are presented. The informed contribution from the activities personnel and the support of nurses is vital to ensure a high quality of social interaction. Sound leadership at the clinical level is essential.

A new unit root test with two structural breaks in level and slope at unknown time

In this paper, we propose a new augmented Dickey–Fuller-type test for unit roots which accounts for
two structural breaks. We consider two different specifications: (a) two breaks in the level of a trending data series and (b) two breaks in the level and slope of a trending data series. The breaks whose time of occurrence is assumed to be unknown are modeled as innovational outliers and thus take effect gradually. Using Monte Carlo simulations, we showthat our proposed test has correct size, stable power, and identifies the structural breaks accurately.

Observer-based controller design of time-delay systems with an interval time-varying delay

This paper considers the problem of designing an observer-based output feedback controller to exponentially stabilize a class of linear systems with an interval time-varying delay in the state vector. The delay is assumed to vary within an interval with known lower and upper bounds. The time-varying delay is not required to be differentiable, nor should its lower bound be zero. By constructing a set of Lyapunov–Krasovskii functionals and utilizing the Newton–Leibniz formula, a delay-dependent stabilizability condition which is expressed in terms of Linear Matrix Inequalities (LMIs) is derived to ensure the closed-loop system is exponentially stable with a prescribed α-convergence rate. The design of an observerbased output feedback controller can be carried out in a systematic and computationally efficient manner via the use of an LMI-based algorithm. A numerical example is given to illustrate the design procedure.

Testing for unit roots in panel time-series models with multiple level breaks

This paper proposes two new unit root tests that are appropriate in the presence of an unknown number of structural breaks in the level of the data. One is based on a single time series and the other is based on a panel of multiple series. For the estimation of the number of breaks and their locations, a simple procedure based on outlier detection is proposed. The limiting distributions of the tests are derived and evaluated in small samples using simulation experiments. The implementation of the tests is illustrated using as an example purchasing power parity.