scholarly journals Smartphone-Based VO2max Measurement With Heart Snapshot in Clinical and Real-world Settings With a Diverse Population: Validation Study

10.2196/26006 ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. e26006
Author(s):  
Dan E Webster ◽  
Meghasyam Tummalacherla ◽  
Michael Higgins ◽  
David Wing ◽  
Euan Ashley ◽  
...  
Keyword(s):  
Heart Rate ◽  
Correlation Coefficient ◽  
Intraclass Correlation Coefficient ◽  
Real World ◽  
Gold Standard ◽  
Clinical Care ◽  
Skin Pigmentation ◽  
Intraclass Correlation ◽  
Step Test ◽  
Validation Data

Background Maximal oxygen consumption (VO2max) is one of the most predictive biometrics for cardiovascular health and overall mortality. However, VO2max is rarely measured in large-scale research studies or routine clinical care because of the high cost, participant burden, and requirement for specialized equipment and staff. Objective To overcome the limitations of clinical VO2max measurement, we aim to develop a digital VO2max estimation protocol that can be self-administered remotely using only the sensors within a smartphone. We also aim to validate this measure within a broadly representative population across a spectrum of smartphone devices. Methods Two smartphone-based VO2max estimation protocols were developed: a 12-minute run test (12-MRT) based on distance measured by GPS and a 3-minute step test (3-MST) based on heart rate recovery measured by a camera. In a 101-person cohort, balanced across age deciles and sex, participants completed a gold standard treadmill-based VO2max measurement, two silver standard clinical protocols, and the smartphone-based 12-MRT and 3-MST protocols in the clinic and at home. In a separate 120-participant cohort, the video-based heart rate measurement underlying the 3-MST was measured for accuracy in individuals across the spectrum skin tones while using 8 different smartphones ranging in cost from US $99 to US $999. Results When compared with gold standard VO2max testing, Lin concordance was pc=0.66 for 12-MRT and pc=0.61 for 3-MST. However, in remote settings, the 12-MRT was significantly less concordant with the gold standard (pc=0.25) compared with the 3-MST (pc=0.61), although both had high test-retest reliability (12-MRT intraclass correlation coefficient=0.88; 3-MST intraclass correlation coefficient=0.86). On the basis of the finding that 3-MST concordance was generalizable to remote settings whereas 12-MRT was not, the video-based heart rate measure within the 3-MST was selected for further investigation. Heart rate measurements in any of the combinations of the six Fitzpatrick skin tones and 8 smartphones resulted in a concordance of pc≥0.81. Performance did not correlate with device cost, with all phones selling under US $200 performing better than pc>0.92. Conclusions These findings demonstrate the importance of validating mobile health measures in the real world across a diverse cohort and spectrum of hardware. The 3-MST protocol, termed as heart snapshot, measured VO2max with similar accuracy to supervised in-clinic tests such as the Tecumseh (pc=0.94) protocol, while also generalizing to remote and unsupervised measurements. Heart snapshot measurements demonstrated fidelity across demographic variation in age and sex, across diverse skin pigmentation, and between various iOS and Android phone configurations. This software is freely available for all validation data and analysis code.

scholarly journals Heart Snapshot: a broadly validated smartphone measure of VO2max for collection of real world data

2020 ◽  
Author(s):  
Dan E. Webster ◽  
Meghasyam Tummalacherla ◽  
Michael Higgins ◽  
David Wing ◽  
Euan Ashley ◽  
...  
Keyword(s):  
Real World ◽  
Gold Standard ◽  
Large Scale ◽  
Digital Health ◽  
Clinical Care ◽  
Skin Pigmentation ◽  
Epidemiologic Studies ◽  
Step Test ◽  
Real World Data ◽  
Laboratory Equipment

AbstractExpanding access to precision medicine will increasingly require that patient biometrics can be measured in remote care settings. VO2max, the maximum volume of oxygen usable during intense exercise, is one of the most predictive biometric risk factors for cardiovascular disease, frailty, and overall mortality.1,2 However, VO2max measurements are rarely performed in clinical care or large-scale epidemiologic studies due to the high cost, participant burden, and need for specialized laboratory equipment and staff.3,4 To overcome these barriers, we developed two smartphone sensor-based protocols for estimating VO2max: a generalization of a 12-minute run test (12-MRT) and a submaximal 3-minute step test (3-MST). In laboratory settings, Lins concordance for these two tests relative to gold standard VO2max testing was pc=0.66 for 12-MRT and pc=0.61 for 3-MST. Relative to “silver standards”5 (Cooper/Tecumseh protocols), concordance was pc=0.96 and pc=0.94, respectively. However, in remote settings, 12-MRT was significantly less concordant with gold standard (pc=0.25) compared to 3-MST (pc=0.61), though both had high test-retest reliability (ICC=0.88 and 0.86, respectively). These results demonstrate the importance of real-world evidence for validation of digital health measurements. In order to validate 3-MST in a broadly representative population in accordance with the All of Us Research Program6 for which this measurement was developed, the camera-based heart rate measurement was investigated for potential bias. No systematic measurement error was observed that corresponded to skin pigmentation level, operating system, or cost of the phone used. The smartphone-based 3-MST protocol, here termed Heart Snapshot, maintained fidelity across demographic variation in age and sex, across diverse skin pigmentation, and between iOS and Android implementations of various smartphone models. The source code for these smartphone measurements, along with the data used to validate them,6 are openly available to the research community.

scholarly journals Corrigendum

2018 ◽  
Vol 25 (2) ◽  
pp. NP3-NP3
Keyword(s):  
Multiple Sclerosis ◽  
Correlation Coefficient ◽  
Intraclass Correlation Coefficient ◽  
Intraclass Correlation ◽  
Online Version ◽  
Step Test ◽  
First Line ◽  
Interclass Correlation Coefficient ◽  
Interclass Correlation ◽  
On Line

Callesen J, Richter C, Kristensen C, et al. Test–retest agreement and reliability of the Six Spot Step Test in persons with multiple sclerosis. Mult Scler. Epub ahead of print 20 December 2017. DOI: 10.1177/1352458517745725 In this article, ‘Intraclass Correlation Coefficient’ appeared incorrectly as ‘Interclass Correlation Coefficient’ on two occasions, once on line eight of the abstract and once on page four, on the first line of paragraph two. This error has now been corrected in the online version of the article.

A Novel Quantitative PCR Approach Targeting Insertion/Deletion Polymorphisms (Indel-PCR) for Chimerism Quantification: Finally High Sensitivity and Quantification Capacity Together

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 4277-4277
Author(s):  
Almudena Navarro-Bailón ◽  
Carolina Martinez-Laperche ◽  
Diego Carbonell ◽  
Elena Buces ◽  
Milagros González-Rivera ◽  
...  
Keyword(s):  
Correlation Coefficient ◽  
Quantitative Pcr ◽  
Intraclass Correlation Coefficient ◽  
Gold Standard ◽  
Conflicts Of Interest ◽  
Recipient Cell ◽  
Intraclass Correlation ◽  
High Sensitivity ◽  
Hematopoietic Stem ◽  
Artificial Mixtures

Abstract Introduction Post-hematopoietic stem cell transplantation (SCT) chimerism monitoring is important to assess engraftment, anticipate relapse and provide information on the development of graft versus host disease, facilitating therapeutic intervention. The aim of this study was to test the technical efficacy and clinical utility of a novel quantitative PCR approach targeting insertion/deletion polymorphisms (indel-PCR). Materials (or patients) and methods This study included 157 samples (81 bone marrow, 60 peripheral blood (PB), 11 T-cells, 2 myeloid cells, 2 CD34-cells, 1 NK-cells purified using immunomagnetic technology) of 24 patients who underwent SCT for haematological malignancies. Additionally, 2 sets of 11 artificial mixtures were created using PB leukocytes of two healthy subjects (a male and a female) with known percentages of male leukocytes (putative recipient): 100, 75, 50, 25, 10, 5, 3, 1, 0.1, 0.01, 0. Chimerism analysis was performed by the gold-standard STR-PCR (AmpFlSTR SGM Plus®, Life Technologies, USA) and by indel-PCR (Mentype® DIPscreen, Mentype® DIPquant, Biotype, Germany). Concordance between both methods was calculated with SPSS using intraclass correlation coefficient. Results The number of informative loci identified with indel-PCR (>3/patient) was higher than with STR-PCR for all patients. Concordance between both methods for the 157 patient samples and 11 artificial mixtures was "very good" (intraclass correlation coefficient=0.96). Of note, analysis of artificial mixtures provides evidence of significantly (≥2 logs) higher sensitivity by indel-PCR (0.01%) than by STR-PCR (1%, Table 1). Moreover, indel-PCR shows unprecedented quantification capacity (Table 1). Out of the 168 samples analyzed, 32 were positive and 15 negative by both methods, while 121 were positive only by indel-PCR (95% with <1% recipient). Clinical outcome and chimerism dynamics of 24 patients are described in figure 1, data of 4 of them were censored (engraftment failure, disease progression, insufficient number of samples). All the samples presented complete donor chimerism by STR-PCR. Of the 9 patients who showed stable or decreasing percentage of recipient cells, only one (11%) presented extramedulary relapse. Of the 11 patients who presented increasing percentage of recipient cells in one determination, relapse occurred in 5 patients (45%, 3/6 patients who did not have further determinations, 2/4 who showed stable or decreasing recipient cell percentage, and 0/1 patient who presented increasing recipient cells in subsequent determinations). Conclusion This novel indel-PCR is a simple and accurate technique that, in comparison with the current gold standard STR-PCR, shows very good concordance and provides higher rates of informative loci per patient, as well as unprecedented combined sensitivity and quantification capacity. Such features allow minutely monitoring chimerism dynamics and might improve clinical management of transplanted patients, specially predicting relapse in those patients who do not have a molecular marker available for disease follow up. Disclosures No relevant conflicts of interest to declare.

scholarly journals Reliability and Usefulness of the 30-15 Intermittent Fitness Test in Male and Female Professional Futsal Players

2017 ◽  
Vol 60 (1) ◽  
pp. 191-198 ◽  
Author(s):  
Santiago Valladares-Rodríguez ◽  
Ezequiel Rey ◽  
Marcos Mecías-Calvo ◽  
Roberto Barcala-Furelos ◽  
Antonio J. Bores-Cerezal
Keyword(s):  
Heart Rate ◽  
Correlation Coefficient ◽  
Intraclass Correlation Coefficient ◽  
Coefficient Of Variation ◽  
Intraclass Correlation ◽  
Meaningful Change ◽  
Good Reliability ◽  
Male And Female ◽  
Fitness Test ◽  
Typical Error

Abstract The purpose of this study was to determine the reliability and usefulness of the 30-15 Intermittent Fitness Test (30-15IFT) in professional male and female futsal players. Thirteen male (24.4 ± 5.6 years; 174.5 ± 10.3 cm; 70.3 ± 9.9 kg) and fourteen female (23.3 ± 4.5 years; 165.8 ± 6.2 cm; 61.7 ± 5.5 kg) professional futsal players performed the 30-15IFT on two occasions, separated by 5 days. Maximal intermittent running velocity (VIFT) and heart rate at exhaustion (HRpeak) data were collected for both tests. Reliability was assessed by the intraclass correlation coefficient (ICC), typical error (TE) expressed as a coefficient of variation (CV), and smallest worthwhile change (SWC). VIFT demonstrated very good reliability between sessions, both for male (ICC = 0.92) and female (ICC = 0.96) players. As the TE for VIFT and HRpeak was similar to the calculated SWC for both male and female players, the usefulness of the test was rated as “medium”. A change in performance of at least 2 stages in male players, or a change of more than 1 stage in female players could be interpreted as a meaningful change in aerobic futsal fitness. The results of this study demonstrate that the 30-15IFT is both a reliable and useful test for male and female professional futsal players.

scholarly journals Construction and validation of a simplified questionnaire for screening of patients with temporomandibular disorder

2020 ◽  
Vol 9 (11) ◽  
pp. e83691110498
Author(s):  
Angela Maria Fernandes Vieira de Paiva ◽  
Laércio Almeida de Melo Melo ◽  
Erika Oliveira de Almeida ◽  
Helson José de Paiva ◽  
Kenio Costa de Lima
Keyword(s):  
Correlation Coefficient ◽  
Intraclass Correlation Coefficient ◽  
Diagnostic Tool ◽  
Gold Standard ◽  
Temporomandibular Disorders ◽  
Temporomandibular Disorder ◽  
Intraclass Correlation ◽  
Test Validation ◽  
Face Validity ◽  
Factorial Validity

Objective: Develop and validate a diagnostic tool of temporomandibular disorders (TMD) compared to the gold standard (RDC/TMD). Methods: Construction and validation of the questionnaire followed a series of steps: test validation, face validity, factorial validity and validation in comparison to the gold standard. Stability of the questionnaires with 5 and 7 items was tested by Intraclass Correlation Coefficient. Results: 130 individuals participated for the factorial validation and 99 for the validation in comparison to the gold standard. The instrument stability was 0.923 for both questionnaires. Considering the total score of the questions for the questionnaire with 7 items, the best result for TMD was assumed for scores from 10 to 21, while 85.1% was also positive in RDC/TMD. Scores from 7 to 9 revealed no TMD, and 96.2% was also negative in RDC/TMD with accuracy of 90.1%. Sensitivity was 95% and specificity 87%. For the questionnaire with 5 items, the best result for TMD was assumed for scores from 7 to 15 while no TMD was associated to scores 5 and 6, with accuracy of 85.8%. Sensitivity was 88% and specificity 84%. Conclusion: Simple and fast questionnaires with reliability for the diagnosis of temporomandibular disorder were obtained.

scholarly journals Biomechanical Measurement of Rabbit Cornea by a Modified Scheimpflug Device

2016 ◽  
Vol 2016 ◽  
pp. 1-6
Author(s):  
Bo Zhang ◽  
Jianjun Gu ◽  
Xiaoxiao Zhang ◽  
Bin Yang ◽  
Zheng Wang ◽  
...  
Keyword(s):  
Bulk Modulus ◽  
Correlation Coefficient ◽  
Intraclass Correlation Coefficient ◽  
Intraclass Correlation ◽  
Anterior Segment ◽  
Intraobserver Reliability ◽  
Rabbit Cornea ◽  
Deformation Response ◽  
Biomechanical Measurements ◽  
Biomechanical Measurement

Purpose. To explore the probability and variation in biomechanical measurements of rabbit cornea by a modified Scheimpflug device.Methods. A modified Scheimpflug device was developed by imaging anterior segment of the model imitating the intact eye at various posterior pressures. The eight isolated rabbit corneas were mounted on the Barron artificial chamber and images of the anterior segment were taken at posterior pressures of 15, 30, 45, 60, and 75 mmHg by the device. The repeatability and reliability of the parameters including CCT, ACD, ACV, and CV were evaluated at each posterior pressure. All the variations of the parameters at the different posterior pressures were calculated.Results. All parameters showed good intraobserver reliability (Cronbach’s alpha; intraclass correlation coefficient,α, ICC > 0.96) and repeatability in the modified Scheimpflug device. With the increase of posterior pressures, the ratio of CCT decreased linearly and the bulk modulus gradually reduced to a platform. The increase of ACD was almost linear with the posterior pressures elevated.Conclusions. The modified Scheimpflug device was a valuable tool to investigate the biomechanics of the cornea. The posterior pressure 15–75 mmHg range produced small viscoelastic deformations and nearly linear pressure-deformation response in the rabbit cornea.

scholarly journals A preliminary study of intensivist-performed DVT ultrasound screening in trauma ICU patients (APSIT Study)

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Lloyd Roberts ◽  
Tom Rozen ◽  
Deirdre Murphy ◽  
Adam Lawler ◽  
Mark Fitzgerald ◽  
...  
Keyword(s):  
Intensive Care ◽  
Deep Vein Thrombosis ◽  
High Risk ◽  
Correlation Coefficient ◽  
Intraclass Correlation Coefficient ◽  
Major Trauma ◽  
Intraclass Correlation ◽  
Trauma Patients ◽  
Vein Thrombosis ◽  
Deep Vein

Abstract Background Multiple screening Duplex ultrasound scans (DUS) are performed in trauma patients at high risk of deep vein thrombosis (DVT) in the intensive care unit (ICU). Intensive care physician performed compression ultrasound (IP-CUS) has shown promise as a diagnostic test for DVT in a non-trauma setting. Whether IP-CUS can be used as a screening test in trauma patients is unknown. Our study aimed to assess the agreement between IP-CUS and vascular sonographer performed DUS for proximal lower extremity deep vein thrombosis (PLEDVT) screening in high-risk trauma patients in ICU. Methods A prospective observational study was conducted at the ICU of Alfred Hospital, a major trauma center in Melbourne, Australia, between Feb and Nov 2015. All adult major trauma patients admitted with high risk for DVT were eligible for inclusion. IP-CUS was performed immediately before or after DUS for PLEDVT screening. The paired studies were repeated twice weekly until the DVT diagnosis, death or ICU discharge. Written informed consent from the patient, or person responsible, or procedural authorisation, was obtained. The individuals performing the scans were blinded to the others’ results. The agreement analysis was performed using Cohen’s Kappa statistics and intraclass correlation coefficient for repeated binary measurements. Results During the study period, 117 patients had 193 pairs of scans, and 45 (39%) patients had more than one pair of scans. The median age (IQR) was 47 (28–68) years with 77% males, mean (SD) injury severity score 27.5 (9.53), and a median (IQR) ICU length of stay 7 (3.2–11.6) days. There were 16 cases (13.6%) of PLEDVT with an incidence rate of 2.6 (1.6–4.2) cases per 100 patient-days in ICU. The overall agreement was 96.7% (95% CI 94.15–99.33). The Cohen’s Kappa between the IP-CUS and DUS was 0.77 (95% CI 0.59–0.95), and the intraclass correlation coefficient for repeated binary measures was 0.75 (95% CI 0.67–0.81). Conclusions There is a substantial agreement between IP-CUS and DUS for PLEDVT screening in trauma patients in ICU with high risk for DVT. Large multicentre studies are needed to confirm this finding.

Test-Retest-Reliability of Computer-Based Metamorphopsia Measurement in Macular Diseases

2020 ◽  
Author(s):  
Daniela Claessens ◽  
Alexander K. Schuster ◽  
Ronald V. Krüger ◽  
Marian Liegl ◽  
Laila Singh ◽  
...  
Keyword(s):  
Macular Edema ◽  
Correlation Coefficient ◽  
Intraclass Correlation Coefficient ◽  
Intraclass Correlation ◽  
Measuring Method ◽  
Repeated Measurements ◽  
Retest Reliability ◽  
Macular Diseases ◽  
Computer Based ◽  
Test Retest Reliability

AbstractIn this study, the test-retest-reliability as one aspect of reliability of metamorphopsia measurements using a computer-based measuring method was determined in patients with macular diseases. Metamorphopsia amplitude, position, and area were quantified using AMD – A Metamorphopsia Detector software (app4eyes GmbH & Co. KG, Germany) in patients with diabetic, myopic, or uveitic macular edema, intermediate or neovascular age-associated macular degeneration, epiretinal membrane, vitelliform maculopathy, Irvine-Gass syndrome, or macular edema due to venous retinal occlusion. The intraclass correlation coefficient (ICC) was calculated in order to determine the repeatability of two repeated measurements and was used as an indicator of the reliability of the measurements. In this study, metamorphopsia measurements were conducted on 36 eyes with macular diseases. Metamorphopsia measurements made using AMD – A Metamorphopsia Detector software were highly reliable and repeatable in patients with maculopathies. The intraclass correlation coefficient of all indices was excellent (0.95 – 0.97). For diseases of the vitreoretinal interface or macular diseases with intra- or subretinal edema, this metamorphopsia measurement represents a supplement for visual function testing in the clinic, as well as in clinical studies.

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