limits of agreement
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Sensors ◽  
2022 ◽  
Vol 22 (1) ◽  
pp. 376
Author(s):  
Cornelis J. de Ruiter ◽  
Erik Wilmes ◽  
Pepijn S. van Ardenne ◽  
Niels Houtkamp ◽  
Reinder A. Prince ◽  
...  

Inertial measurement units (IMUs) fixed to the lower limbs have been reported to provide accurate estimates of stride lengths (SLs) during walking. Due to technical challenges, validation of such estimates in running is generally limited to speeds (well) below 5 m·s−1. However, athletes sprinting at (sub)maximal effort already surpass 5 m·s−1 after a few strides. The present study aimed to develop and validate IMU-derived SLs during maximal linear overground sprints. Recreational athletes (n = 21) completed two sets of three 35 m sprints executed at 60, 80, and 100% of subjective effort, with an IMU on the instep of each shoe. Reference SLs from start to ~30 m were obtained with a series of video cameras. SLs from IMUs were obtained by double integration of horizontal acceleration with a zero-velocity update, corrected for acceleration artefacts at touch-down of the feet. Peak sprint speeds (mean ± SD) reached at the three levels of effort were 7.02 ± 0.80, 7.65 ± 0.77, and 8.42 ± 0.85 m·s−1, respectively. Biases (±Limits of Agreement) of SLs obtained from all participants during sprints at 60, 80, and 100% effort were 0.01% (±6.33%), −0.75% (±6.39%), and −2.51% (±8.54%), respectively. In conclusion, in recreational athletes wearing IMUs tightly fixed to their shoes, stride length can be estimated with reasonable accuracy during maximal linear sprint acceleration.


Author(s):  
Sirkka-Liisa Lauronen ◽  
Maija-Liisa Kalliomäki ◽  
Jarkko Kalliovalkama ◽  
Antti Aho ◽  
Heini Huhtala ◽  
...  

AbstractBecause of the difficulties involved in the invasive monitoring of conscious patients, core temperature monitoring is frequently neglected during neuraxial anaesthesia. Zero heat flux (ZHF) and double sensor (DS) are non-invasive methods that measure core temperature from the forehead skin. Here, we compare these methods in patients under spinal anaesthesia. Sixty patients scheduled for elective unilateral knee arthroplasty were recruited and divided into two groups. Of these, thirty patients were fitted with bilateral ZHF sensors (ZHF group), and thirty patients were fitted with both a ZHF sensor and a DS sensor (DS group). Temperatures were saved at 5-min intervals from the beginning of prewarming up to one hour postoperatively. Bland–Altman analysis for repeated measurements was performed and a proportion of differences within 0.5 °C was calculated as well as Lin`s concordance correlation coefficient (LCCC). A total of 1261 and 1129 measurement pairs were obtained. The mean difference between ZHF sensors was 0.05 °C with 95% limits of agreement − 0.36 to 0.47 °C, 99% of the readings were within 0.5 °C and LCCC was 0.88. The mean difference between ZHF and DS sensors was 0.33 °C with 95% limits of agreement − 0.55 to 1.21 °C, 66% of readings were within 0.5 °C and LCCC was 0.59. Bilaterally measured ZHF temperatures were almost identical. DS temperatures were mostly lower than ZHF temperatures. The mean difference between ZHF and DS temperatures increased when the core temperature decreased.Trial registration: The study was registered in ClinicalTrials.gov on 13th May 2019, Code NCT03408197.


2022 ◽  
Vol 22 (1) ◽  
Author(s):  
Catherine Muthoni Njeru ◽  
J. Mark Ansermino ◽  
William M. Macharia ◽  
Dustin T. Dunsmuir

Abstract Background Respiratory rate is difficult to measure, especially in neonates who have an irregular breathing pattern. The World Health Organisation recommends a one-minute count, but there is limited data to support this length of observation. We sought to evaluate agreement between the respiratory rate (RR) derived from capnography in neonates, over 15 s, 30 s, 120 s and 300 s, against the recommended 60 s. Methods Neonates at two hospitals in Nairobi were recruited and had capnograph waveforms recorded using the Masimo Rad 97. A single high quality 5 min epoch was randomly chosen from each subject. For each selected epoch, the mean RR was calculated using a breath-detection algorithm applied to the waveform. The RR in the first 60 s was compared to the mean RR measured over the first 15 s, 30 s, 120 s, full 300 s, and last 60 s. We calculated bias and limits of agreement for each comparison and used Bland-Altman plots for visual comparisons. Results A total of 306 capnographs were analysed from individual subjects. The subjects had a median gestation age of 39 weeks with slightly more females (52.3%) than males (47.7%). The majority of the population were term neonates (70.1%) with 39 (12.8%) having a primary respiratory pathology. There was poor agreement between all the comparisons based on the limits of agreement [confidence interval], ranging between 11.9 [− 6.79 to 6.23] breaths per minute in the one versus 2 min comparison, and 34.7 [− 17.59 to 20.53] breaths per minute in the first versus last minute comparison. Worsening agreement was observed in plots with higher RRs. Conclusions Neonates have high variability of RR, even over a short period of time. A slight degradation in the agreement is noted over periods shorter than 1 min. However, this is smaller than observations done 3 min apart in the same subject. Longer periods of observation also reduce agreement. For device developers, precise synchronization is needed when comparing devices to reduce the impact of RR variation. For clinicians, where possible, continuous or repeated monitoring of neonates would be preferable to one time RR measurements.


2021 ◽  
Vol 17 (1) ◽  
pp. 324-330
Author(s):  
Federica Sancassiani ◽  
Sara Gambino ◽  
Jutta Lindert ◽  
Lapo Sali ◽  
Irene Pinna ◽  
...  

Background: Patients' satisfaction is an indicator of technical, instrumental, environmental, and interpersonal aspects of care. It shows how much the health service “as a whole organization” meets the patients’ psychosocial expectations and if the health professionals combine their technical competence with relational skills. The Treatment Perception Questionnaire (TPQ) is a brief instrument developed in the United Kingdom for research with substance abuse disorder populations. The present study aimed at evaluating the reliability and test-retest stability of the TPQ Italian translation in a sample of patients with solid and blood cancers. Methods: The TPQ was administered to 263 people with solid and blood cancers. Test-retest reliability was evaluated in a subgroup of 116 participants who completed the TPQ again after 3 months. Results: The reliability of TPQ was good. Cronbach’s alpha: 0.83 (95%CI: 0.79-0.86), 0.66 (0.59-0.72), 0.71 (0.65-0.769), respectively, in the total test, and in subscales on “staff perception”, and “program perception”. Test-retest reliability was 0.82 (0.77-0.87). The mean difference between the first and the second assessment was 1.0 (SD = 7.1; 95% CI -0.35 to 2.33). By plotting the differences and the means of the two assessments, 5/116 cases (4.3%) were outside the upper and lower limits of agreement. Conclusions: This study points out good reliability and test-retest stability of the TPQ in the oncology field. The TPQ can be used to assess variation over time about satisfaction with care in patients with oncological diseases, favoring the identification of unmet patients’ needs about the quality of the service.


Diagnostics ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 93
Author(s):  
Yu-Sen Huang ◽  
Emi Niisato ◽  
Mao-Yuan Marine Su ◽  
Thomas Benkert ◽  
Ning Chien ◽  
...  

This prospective study aimed to investigate the ability of spiral ultrashort echo time (UTE) and compressed sensing volumetric interpolated breath-hold examination (CS-VIBE) sequences in magnetic resonance imaging (MRI) compared to conventional VIBE and chest computed tomography (CT) in terms of image quality and small nodule detection. Patients with small lung nodules scheduled for video-assisted thoracoscopic surgery (VATS) for lung wedge resection were prospectively enrolled. Each patient underwent non-contrast chest CT and non-contrast MRI on the same day prior to thoracic surgery. The chest CT was performed to obtain a standard reference for nodule size, location, and morphology. The chest MRI included breath-hold conventional VIBE and CS-VIBE with scanning durations of 11 and 13 s, respectively, and free-breathing spiral UTE for 3.5–5 min. The signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and normal structure visualizations were measured to evaluate MRI quality. Nodule detection sensitivity was evaluated on a lobe-by-lobe basis. Inter-reader and inter-modality reliability analyses were performed using the Cohen κ statistic and the nodule size comparison was performed using Bland–Altman plots. Among 96 pulmonary nodules requiring surgery, the average nodule diameter was 7.7 ± 3.9 mm (range: 4–20 mm); of the 73 resected nodules, most were invasive cancer (74%) or pre-invasive carcinoma in situ (15%). Both spiral UTE and CS-VIBE images achieved significantly higher overall image quality scores, SNRs, and CNRs than conventional VIBE. Spiral UTE (81%) and CS-VIBE (83%) achieved a higher lung nodule detection rate than conventional VIBE (53%). Specifically, the nodule detection rate for spiral UTE and CS-VIBE reached 95% and 100% for nodules >8 and >10 mm, respectively. A 90% detection rate was achieved for nodules of all sizes with a part-solid or solid morphology. Spiral UTE and CS-VIBE under-estimated the nodule size by 0.2 ± 1.4 mm with 95% limits of agreement from −2.6 to 2.9 mm and by 0.2 ± 1.7 mm with 95% limits of agreement from −3.3 to 3.5 mm, respectively, compared to the reference CT. In conclusion, chest CT remains the gold standard for lung nodule detection due to its high image resolutions. Both spiral UTE and CS-VIBE MRI could detect small lung nodules requiring surgery and could be considered a potential alternative to chest CT; however, their clinical application requires further investigation.


2021 ◽  
Vol 16 (2) ◽  
pp. 161-167
Author(s):  
Zeynep Eylül Ercan ◽  

Central corneal thickness (CCT) measurements are important for diagnosis, treatment, and surgery planning in ophthalmology. The purpose of this study was to see whether CCT measurements taken with Tono-pachymeter and Scheimpflug- Placido Topography had any significant differences. Tono-pachymeter and topography CCT measurements were taken (n=400). Inter-measurement agreement between them was determined using Bland-Altman Plot analysis. Age groups were also formed as group 1 (aged 18-50 years, 94 males, 106 females) and group 2 (age >51 years, 100 males, 100 females). Mean CCTs measured by Tonopachymeter and topography were 563.77 +±26.43 and 560.88 + 26.341 microns. Bland-Altman Plot analysis showed in total, 13 were above the upper limit and 5 were under the minimum limit of agreement with regression analysis showing no significant relationships (p=0.213). Group 1 had 7 above and 2 below from the limits of agreement. Group two had 9 above and 2 below from the limits of agreement. Both groups showed insignificant differences between devices (p=0.07 and p=0.86). Tono-pachymeter and Scheimpflug-Placido Topography give reliable CCT results within each other. However, since the limit of agreement ranges can still affect one-to-one patient evaluations, we recommend clinics that use these devices to not interchange measurements in practice.


2021 ◽  
pp. 270-278

Background: To evaluate improvements in clinical measures and symptoms in children and young adults with accommodative insufficiency in an open trial of office-based vergence and accommodative therapy. Methods: Major eligibility requirements included ages 9 to 30 years and amplitude of accommodation (AA) ≥2 diopters (D) below Hoffstetter’s minimum. Participants completed 8 weekly, 1-hour sessions of office-based vergence and accommodative therapy. Therapy procedures followed the Convergence Insufficiency Treatment Trial (CITT) therapy protocol with emphasis on accommodative procedures. Clinical measures of accommodation and symptoms (Convergence Insufficiency Symptom Survey [CISS]) were assessed at baseline and after therapy. Results were evaluated using the Student’s t test and Kruskal-Wallis test. Repeatability of CISS scores at baseline was assessed using Bland Altman 95% Limits of Agreement (LoA) and Interclass Correlation Coefficient (ICC). Results: Eighteen participants (mean age 17.4 ± 8.0 years) were enrolled; sixteen completed the study. The mean AA improved significantly from 5.5D OD and OS at baseline to 12.4D OD and 12.8D OS at outcome (p<0.001). Mean monocular accommodative facility (AF) also increased significantly in both eyes from 6.6 cycles per min (cpm) OD and 7.4cpm OS at baseline to 14.2cpm OD and OS at outcome (p≤0.0009). Amplitude-scaled monocular AF also showed significant improvements (p≤0.034 for both). Mean CISS score improved 10.50 points (p=0.0003). Significantly greater improvements in AA were observed in children (9.0D) than in adults (4.3D) in the right eye (p=0.007 for both comparisons). Conversely mean improvement in CISS score was significantly greater in adults than in children (p=0.039). Repeated CISS scores differed by, on average,1.47 points (95% limits of agreement:-5.19, 8.13; p=0.12). The ICC was 0.95 with a 95% confidence interval of 0.87 to 0.98. Conclusion: Eight weekly sessions of office-based accommodative vergence therapy combined with homebased- reinforcement therapy resulted in improvements of symptoms and clinical measures of accommodation in children and young adults with accommodative insufficiency.


Author(s):  
Goncalo V. Mendonca ◽  
Inês Santos ◽  
Bo Fernhall ◽  
Tracy Baynard

Estimations based on the available equations for predicting oxygen uptake (VO2) from treadmill speed of locomotion are not appropriate for individuals with Down syndrome (DS). We aimed at developing prediction models for peak absolute oxygen uptake (VO2peak) and peak heart rate (HRpeak) based on retrospective data from a healthy population with and without Down syndrome (DS). A cross-sectional analysis of VO2peak and HRpeak was conducted in 196 and 187 persons with and without DS, respectively, aged from 16-45 years. Non-exercise data alone versus combined with HRpeak were used to develop equations predictive of absolute VO2peak. Prediction equations for HRpeak were also developed. Two additional samples of participants (30 with, 29 without DS) enabled model cross-validation. Relative VO2peak and HRpeak were lowest for persons with DS across all ages (~ 40% and 20 bpm, respectively). For persons with DS, VO2peak predictions provided no differences compared with actual values. Predicted HRpeak was similar to actual values in both groups of participants. Large limits of agreement were obtained for VO2peak (DS: 735, non-DS: 558.2 mL.min-1) and HRpeak (DS: 24.8, non-DS: 16.6 bpm). Persons with DS exhibit low levels of VO2peak and HRpeak in all age groups included in this study. It is possible to estimate absolute VO2peak in persons with DS using non-exercise variables. HRpeak can be accurately estimated in groups of people with and without DS. Yet, because of large limits of agreement, caution is advised if using these equations for individual estimations of VO2peak or HRpeak in either population.


Author(s):  
Thomas E. Kozlovich ◽  
Stephen C. Jones ◽  
Nina R. Kieves

Abstract OBJECTIVE To determine whether use of a protective cover would affect temporospatial gait or ground reaction force (GRF) measurements obtained from dogs walking on a validated pressure-sensitive walkway (PSW). ANIMALS 5 healthy dogs. PROCEDURES In a crossover study design, all dogs were walked across a calibrated PSW with and without a protective cover in place in random order. Temporospatial gait data and GRFs obtained with and without the cover in place were compared. RESULTS No significant differences were identified in temporospatial gait measurements obtained with versus without the cover in place. The bias was low for all variables, and the 95% limits of agreement included 0. In contrast, significant differences were found between measurements obtained with versus without the cover in place for most GRFs, with measurements obtained with the cover in place significantly lower than those obtained without a cover. CLINICAL RELEVANCE Results suggested that for dogs walking over a PSW, GRFs, but not temporospatial gait variables, would be significantly lower if a protective cover was placed over the walkway, compared with values obtained without a cover in place.


Stats ◽  
2021 ◽  
Vol 4 (4) ◽  
pp. 1080-1090
Author(s):  
Oke Gerke ◽  
Sören Möller

Bland–Altman agreement analysis has gained widespread application across disciplines, last but not least in health sciences, since its inception in the 1980s. Bayesian analysis has been on the rise due to increased computational power over time, and Alari, Kim, and Wand have put Bland–Altman Limits of Agreement in a Bayesian framework (Meas.Phys.Educ.Exerc.Sci.2021,25,137–148). We contrasted the prediction of a single future observation and the estimation of the Limits of Agreement from the frequentist and a Bayesian perspective by analyzing interrater data of two sequentially conducted, preclinical studies. The estimation of the Limits of Agreement θ1 and θ2 has wider applicability than the prediction of single future differences. While a frequentist confidence interval represents a range of nonrejectable values for null hypothesis significance testing of H0: θ1 ≤ -δ or θ2 ≥ δ against H1: θ1 > -δ and θ2 < δ, with a predefined benchmark value δ, Bayesian analysis allows for direct interpretation of both the posterior probability of the alternative hypothesis and the likelihood of parameter values. We discuss group-sequential testing and nonparametric alternatives briefly. Frequentist simplicity does not beat Bayesian interpretability due to improved computational resources, but the elicitation and implementation of prior information demand caution. Accounting for clustered data (e.g., repeated measurements per subject) is well-established in frequentist, but not yet in Bayesian Bland–Altman analysis.


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