Detecting atrial fibrillation in the polysomnography-derived electrocardiogram: a software validation study.

PURPOSE: The present study validated a software-based electrocardiogram (ECG) analysis tool for detection of atrial fibrillation (AF) and risk for AF using polysomnography (PSG)-derived ECG recordings. METHODS: The Stroke Risk Analysis® (SRA®) software was applied to 3-channel ECG tracings from diagnostic PSG performed in enrolled subjects including a subgroup of subjects with previously documented AF. No subjects used positive airway pressure therapy. All ECG recordings were visually analyzed by a blinded cardiologist. RESULTS: Of subjects enrolled in the study, 93 had previously documented AF and 178 of 186 had an ECG that could be analyzed by either method. In subjects with known history of AF, automated analysis using SRA® classified 47 out of 87 ECG as either manifest AF or showing increased risk for paroxysmal AF (PAF) by SRA® (sensitivity 0.54, specificity 0.86). On visual analysis, 36/87 ECG showed manifest AF and 51/87 showed sinus rhythm. Among the latter subgroup, an increased risk for PAF was ascribed by SRA® in 11 cases (sensitivity 0.22, specificity 0.78) and by expert visual analysis in 5 cases (sensitivity 0.1, specificity 0.90). Among 36/178 ECG with manifest AF on visual analysis, 33 were correctly identified by the SRA® software (sensitivity and specificity 0.92). CONCLUSION: Sleep studies provide a valuable source of ECG recordings that can be easily subjected to software-based analysis in order to identify manifest AF and automatically assess the risk of PAF. For optimal evaluability of data, multiple channel ECG tracings are desirable. For assessment of PAF risk, the SRA® analysis probably excels visual analysis, but sensitivity of both methods is low, reflecting that repeated ECG recording remains essential.

Ultrasound Calculation of Fat Volume for Liposuction: A Clinical Software Validation.

BACKGROUND: Fat manipulation procedures such as liposuction contain a degree of subjectivity primarily guided by the surgeon's visual or tactile perception of the underlying fat. Currently, there is no cost-effective, direct method to objectively measure fat depth and volume in real time. OBJECTIVES: Utilizing innovative ultrasound-based software, the authors aimed to validate fat tissue volume and distribution measurements in the preoperative setting. METHODS: Eighteen participants were recruited to evaluate the accuracy of the new software. Recruited participants underwent ultrasound scans within the preoperative markings of the study area before surgery. Ultrasound-estimated fat profiles were generated with the in-house software and compared directly with the intraoperative aspirated fat recorded after gravity separation. RESULTS: Participants' mean age and BMI were 47.6 (11.3) years and 25.6 (2.3) kg/m2, respectively. Evaluation of trial data showed promising results following the use of a Bland Altman agreement analysis. For the 18 patients and 44 volumes estimated, 43 of 44 measurements fell within a confidence interval of 95% when compared with the clinical lipoaspirate (dry) volumes collected postsurgery. The bias was estimated at 9.15 mL with a standard deviation of 17.08 mL and 95% confidence interval between -24.34 mL and 42.63 mL. CONCLUSIONS: Preoperative fat assessment measurements agreed significantly with intraoperative lipoaspirate volumes. The pilot study demonstrates, for the first time, a novel companion tool with the prospect of supporting surgeons in surgical planning, measuring, and executing the transfer of adipose tissues.

Code Review as a Simple Trick to Enhance Reproducibility, Accelerate Learning, and Improve the Quality of Your Team's Research.

Programming for data wrangling and statistical analysis is an essential technical tool of modern epidemiology, yet many epidemiologists receive limited formal training in strategies to optimize the quality of our code. In complex projects, coding mistakes are easy to make, even for skilled practitioners. Such mistakes can lead to invalid research claims that reduce the credibility of the field. Code review is a straightforward technique used by the software industry to reduce the likelihood of coding bugs. The systematic implementation of code review in epidemiologic research projects could not only improve science but also decrease stress, accelerate learning, contribute to team building, and codify best practices. In the present article, we argue for the importance of code review and provide some recommendations for successful implementation for 1) the research laboratory, 2) the code author (the initial programmer), and 3) the code reviewer. We outline a feasible strategy for implementation of code review, though other successful implementation processes are possible to accommodate the resources and workflows of different research groups, including other practices to improve code quality. Code review isn't always glamorous, but it is critically important for science and reproducibility. Humans are fallible; that's why we need code review.

Rationale and design of a large population study to validate software for the assessment of atrial fibrillation from data acquired by a consumer tracker or smartwatch: The Fitbit heart study.

BACKGROUND: Early detection of atrial fibrillation or flutter (AF) may enable prevention of downstream morbidity. Consumer wrist-worn wearable technology is capable of detecting AF by identifying irregular pulse waveforms using photoplethysmography (PPG). The validity of PPG-based software algorithms for AF detection requires prospective assessment. METHODS: The Fitbit Heart Study (NCT04380415) is a single-arm remote clinical trial examining the validity of a novel PPG-based software algorithm for detecting AF. The proprietary Fitbit algorithm examines pulse waveform intervals during analyzable periods in which participants are sufficiently stationary. Fitbit consumers with compatible wrist-worn trackers or smartwatches were invited to participate. Enrollment began May 6, 2020 and as of October 1, 2020, 455,699 participants enrolled. Participants in whom an irregular heart rhythm was detected were invited to attend a telehealth visit and eligible participants were then mailed a one-week single lead electrocardiographic (ECG) patch monitor. The primary study objective is to assess the positive predictive value of an irregular heart rhythm detection for AF during the ECG patch monitor period. Additional objectives will examine the validity of irregular pulse tachograms during subsequent heart rhythm detections, self-reported AF diagnoses and treatments, and relations between irregular heart rhythm detections and AF episode duration and time spent in AF. CONCLUSIONS: The Fitbit Heart Study is a large-scale remote clinical trial comprising a unique software algorithm for detection of AF. The study results will provide critical insights into the use of consumer wearable technology for AF detection, and for characterizing the nature of AF episodes detected using consumer-based PPG technology.

Quantitative imaging decision support (QIDSTM) tool consistency evaluation and radiomic analysis by means of 594 metrics in lung carcinoma on chest CT scan.

OBJECTIVE: To evaluate the consistency of the quantitative imaging decision support (QIDSTM) tool and radiomic analysis using 594 metrics in lung carcinoma on chest CT scan. MATERIALS AND METHODS: We included, retrospectively, 150 patients with histologically confirmed lung cancer who underwent chemotherapy and baseline and follow-ups CT scans. Using the QIDSTM platform, 3 radiologists segmented each lesion and automatically collected the longest diameter and the density mean value. Inter-observer variability, Bland Altman analysis and Spearman's correlation coefficient were performed. QIDSTM tool consistency was assessed in terms of agreement rate in the treatment response classification. Kruskal Wallis test and the least absolute shrinkage and selection operator (LASSO) method with 10-fold cross validation were used to identify radiomic metrics correlated with lesion size change. RESULTS: Good and significant correlation was obtained between the measurements of largest diameter and of density among the QIDSTM tool and the radiologists measurements. Inter-observer variability values were over 0.85. HealthMyne QIDSTM tool quantitative volumetric delineation was consistent and matched with each radiologist measurement considering the RECIST classification (80-84%) while a lower concordance among QIDSTM and the radiologists CHOI classification was observed (58-63%). Among 594 extracted metrics, significant and robust predictors of RECIST response were energy, histogram entropy and uniformity, Kurtosis, coronal long axis, longest planar diameter, surface, Neighborhood Grey-Level Different Matrix (NGLDM) dependence nonuniformity and low dependence emphasis as Volume, entropy of Log(2.5 mm), wavelet energy, deviation and root man squared. CONCLUSION: In conclusion, we demonstrated that HealthMyne quantitative volumetric delineation was consistent and that several radiomic metrics extracted by QIDSTM were significant and robust predictors of RECIST response.

MIScnn: a framework for medical image segmentation with convolutional neural networks and deep learning.

BACKGROUND: The increased availability and usage of modern medical imaging induced a strong need for automatic medical image segmentation. Still, current image segmentation platforms do not provide the required functionalities for plain setup of medical image segmentation pipelines. Already implemented pipelines are commonly standalone software, optimized on a specific public data set. Therefore, this paper introduces the open-source Python library MIScnn. IMPLEMENTATION: The aim of MIScnn is to provide an intuitive API allowing fast building of medical image segmentation pipelines including data I/O, preprocessing, data augmentation, patch-wise analysis, metrics, a library with state-of-the-art deep learning models and model utilization like training, prediction, as well as fully automatic evaluation (e.g. cross-validation). Similarly, high configurability and multiple open interfaces allow full pipeline customization. RESULTS: Running a cross-validation with MIScnn on the Kidney Tumor Segmentation Challenge 2019 data set (multi-class semantic segmentation with 300 CT scans) resulted into a powerful predictor based on the standard 3D U-Net model. CONCLUSIONS: With this experiment, we could show that the MIScnn framework enables researchers to rapidly set up a complete medical image segmentation pipeline by using just a few lines of code. The source code for MIScnn is available in the Git repository: https://github.com/frankkramer-lab/MIScnn .

Design and clinical validation of a software program for automated measurement of mammographic breast density.

BACKGROUND: Mammographic breast density is an important predictor of breast cancer, but its measurement has limitations related to subjectivity of visual evaluation or to difficult access for automatic volumetric measurement methods. Herein, we describe the design and clinical validation of Aguida, a software program for automated quantification of breast density from flat mammography images. MATERIALS AND METHODS: The software program was developed in MatLab. After image segmentation separating the background from the breast image, the operator positions a cursor defining a region of interest on the pectoralis major muscle from the mediolateral oblique view. Then, in the craniocaudal view, the threshold for separation of the dense tissue is based on the optical density of the pectoral muscle, and the proportion of dense tissue is calculated by the program. Mammograms obtained from 2 different occasions in 291 women were used for clinical evaluation. RESULTS: The intraclass correlation coefficient (ICC) between breast density measurements by the software and by a radiologist was 0.96, with a bias of only 0.67 percentage points and a 95% limit of agreement of 13.5 percentage points; the ICC was 0.94 in the interobserver reliability assessment by two radiologists with different experience; and the ICC was 0.98 in the intraobserver reliability assessment. The distribution among the density classes was close to the values obtained with the volumetric software. CONCLUSIONS: Measurement of breast density with the Aguida program from flat mammography images showed high agreement with the visual determination by radiologists, and high inter- and intra-observer reliability.

Validity and reliability of a computer-vision-based smartphone app for measuring barbell trajectory during the snatch.

The purpose of this study was to investigate the validity of a smartphone app to measure biomechanical barbell parameters during the snatch. Ten collegiate NCAA division I athletes performed two repetitions each at 40, 50, 60, 70, and 80% of their 1-repetition maximum snatch. Barbell motions were simultaneously recorded with a motion capture system and the smartphone app. The motion capture system recorded the 3-D position of a reflective marker attached to the end of the barbell while the smartphone app was used to record sagittal plane video and track the shape of the weight plate from which the barbell center was derived. Peak forward (PFD) and backward (PBD) displacements and peak vertical displacement (PVD) and velocity (PVV) were calculated from both sets of data. Significant, strong to very strong Pearson's product-moment correlation coefficients between both systems were noted for all parameters (r = 0.729-0.902, all p < 0.001). Small significant biases between systems were observed for PVD (ES = 0.284, p < 0.001) and PFD (ES=0.340, p < 0.01), while trivial to small, non-significant biases were observed for PBD (ES = 0.143) and PVV (ES = -0.100). Collectively, the results suggest that the app can provide biomechanical data of barbell motions similar to a 3-D motion capture system.

iDNA6mA-PseKNC: Identifying DNA N6-methyladenosine sites by incorporating nucleotide physicochemical properties into PseKNC.

N6-methyladenine (6mA) is one kind of post-replication modification (PTM or PTRM) occurring in a wide range of DNA sequences. Accurate identification of its sites will be very helpful for revealing the biological functions of 6mA, but it is time-consuming and expensive to determine them by experiments alone. Unfortunately, so far, no bioinformatics tool is available to do so. To fill in such an empty area, we have proposed a novel predictor called iDNA6mA-PseKNC that is established by incorporating nucleotide physicochemical properties into Pseudo K-tuple Nucleotide Composition (PseKNC). It has been observed via rigorous cross-validations that the predictor's sensitivity (Sn), specificity (Sp), accuracy (Acc), and stability (MCC) are 93%, 100%, 96%, and 0.93, respectively. For the convenience of most experimental scientists, a user-friendly web server for iDNA6mA-PseKNC has been established at http://lin-group.cn/server/iDNA6mA-PseKNC, by which users can easily obtain their desired results without the need to go through the complicated mathematical equations involved.

Validation of ThermoHuman automatic thermographic software for assessing foot temperature before and after running.

The aim of the study was to evaluate an automatic thermographic software package (ThermoHuman®) for assessing skin temperature on the soles of the feet before and after running and to compare it with two manual definitions of the regions of interest (ROIs). 120 thermal images of the soles of the feet of 30 participants, at two measurement points (before and after running 30 min) and on two measurement days were analyzed. Three different models of thermographic image analyses were used to obtain the mean temperature of 9 ROIs: A) ThermoHuman (automatic definition of ROIs using ThermoHuman® software), B) Manual (manual delimitation of ROIs by proportion criteria), and C) Manual-TH (manual delimitation of ROIs in an attempt to replicate the regions analyzed by ThermoHuman). ThermoHuman resulted in an 86% reduction in time involved compared to manual delimitation. Fourteen of the 120 images (12%) presented some error in one or more of the ROI delimitations. Although the three procedures presented significant differences between them (53% in the comparison between ThermoHuman and Manual, 47% between ThermoHuman and Manual-TH, and 28% between Manual and Manual-TH), all differences had a small effect size (ES 0.2-0.4) or lower (ES < 0.2). Bland-Altman plots showed similar 95% limits of agreement between the three procedures before and after running. Intraclass correlation coefficient analysis of the three procedures presented excellent reliability (ICC>0.8). In conclusion, ThermoHuman® software was observed to be time-saving for image analysis with excellent reliability. Although results suggest that ThermoHuman® and manual methods are both valid in themselves, combining them is not recommended due to the differences observed between them.

Assessment of Turkey IVF (In Vitro Fertilization) websites according to the American Society for Reproductive Medicine (ASRM)/Society for Assisted Reproductive Technology (SART) guidelines.

OBJECTIVE: To evaluate websites of in-vitro fertilisation centres in terms of standardised ethical guidelines for advertising. METHODS: The cross-sectional study was conducted in Turkey from February to April 2017. A total of 148 IVF centre websites were evaluated in terms of objective criteria in accordance with American Medical Association, American College of Obstetricians and Gynaecologists, American Society for Reproductive Medicine / Society for Assisted Reproductive. Technology guidelines for advertising. Websites were surveyed with attention paid to success rates, testimonials, sales promotions, price, psychological support offered as part of the service, regulating / certifying bodies, misleading language, and the ethical principles of autonomy, beneficence, non-maleficence and justice. Data was analysed using SPSS 23. RESULTS: Out of 193 centres, 148(76.7%) had active websites; 104(70.3%) private, 38(25.7%) in university hospitals and 6(4%) in state hospitals. Of them, 103(69.6%) centres used at least one example of misleading language when compared to the relevant guidelines. Among these centres, 82(79.6%) were private, 18(17.5%) university hospitals and 3(2.9%) were state hospitals. CONCLUSIONS: A massive majority of websites related to in-vitro fertilisation centres did not follow standardised guidelines for advertising.

Novel phenotype-disease matching tool for rare genetic diseases.

PURPOSE: To improve the accuracy of matching rare genetic diseases based on patient's phenotypes. METHODS: We introduce new methods to prioritize diagnosis of genetic diseases based on integrated semantic similarity (method 1) and ontological overlap (method 2) between the phenotypes expressed by a patient and phenotypes annotated to known diseases. RESULTS: We evaluated the performance of our methods by two sets of simulated data and one set of patient's data derived from electronic health records. We demonstrated that the two methods achieved significantly improved performance compared with previous methods in correctly prioritizing candidate diseases in all of the three sets. Our methods are freely available as a web application ( https://gddp. RESEARCH: cchmc.org/ ) to aid diagnosis of genetic diseases. CONCLUSION: Our methods can capture the diagnostic information embedded in the phenotype ontology, consider all phenotypes exhibited by a patient, and are more robust than the existing methods when phenotypes are incorrectly or imprecisely specified. These methods can assist the diagnosis of rare genetic diseases and help the interpretation of the results of DNA tests.

In vivo validation of Dosemap software use in interventional cardiology with dosimetrics indicators and peak skin dose evaluation.

OBJECTIVES: The aim of this study was to determine the accuracy of DoseMap™ software as compared to gafchromic film in real clinical practices. BACKGROUND: The radiation exposure from cardiovascular procedures could expose patients to potential risk of cancer and/or skin injury. New tools like Dosemap software were developed to estimate the patient skin dose in the cardiac catheterization laboratory. However, little data are available to validate this estimation of patient radiation skin dose. METHODS: This is a prospective cross-sectional study comparing the peak skin dose (PSD) measured by gafchromic film used as reference with an estimated PSD given by Dosemap software, in patients with BMI > 30 kg/m2 undergoing elective diagnostic and/or therapeutic interventional cardiology procedures, from April 2016 to December 2016, at the Brest University Hospital Centre, France. RESULTS: After four exclusions of patients for poor quality of gafchromic films, 90 patients were included, with 58 angiography (67.4%), 14 percutaneous interventions (16.3%), and 14 both (16.3%). The median PSDDosemap and PSDFilm were similar with 157 mGy [IQR: 99; 273] versus 158 mGy [IQR: 101; 295] (P = 0.65), respectively, with an excellent correlation (r = 0.95). The comparison between cumulative air kerma and PSDFilm was different 366 mGy [IQR: 246; 575] versus 158 mGy [IQR: 101; 295] (P < 0.01) with moderate correlation (r = 0.79). No correlation was found between the dose area product and PSDFilm (r = 0.51). CONCLUSION: DoseMap is an effective and valid method as compared to gafchromic films to estimate PSDs during interventional cardiologic procedures.

A New Methodology to Determine Apposition, Dilatation, and Position of Endografts in the Descending Thoracic Aorta After Thoracic Endovascular Aortic Repair.

Purpose: To validate computed tomography angiography (CTA)-applied software to assess apposition, dilatation, and position of endografts in the proximal and distal landing zones after thoracic endovascular aortic repair (TEVAR) of thoracic aortic aneurysm. Materials and Methods: Twenty-two patients (median age 75.5 years; 11 men) with a degenerative descending thoracic aortic aneurysm treated with TEVAR with at least one postoperative CTA were selected from a single center's database. New CTA-applied software was used to determine the available apposition surface in the proximal and distal landing zones, apposition of the endograft fabric with the aortic wall, shortest apposition length, endograft inflow and outflow diameters, shortest distance between the left subclavian artery and the proximal endograft fabric, and shortest distance between the celiac trunk and the distal endograft fabric on each CTA. Interobserver variability for these parameters was assessed with the repeatability coefficient and the intraclass correlation coefficient. Results: Excellent interobserver agreement was found for all measurements. Interobserver variability of surface and shortest apposition length calculations was larger for the distal site compared with the proximal site, with a mean difference of 10% vs 2% of the mean available apposition surface, 12% vs 5% of the endograft apposition surface, and 16% vs 8% of the shortest apposition length, respectively. Inflow and outflow diameters of the endograft showed low variability, with a mean difference of 0.1 mm with 95% of the interobserver difference within 1.8 mm. Mean interobserver differences of the proximal and distal shortest fabric distances were 1.0 and 0.9 mm (both 2% of the mean lengths). Conclusion: Assessment of apposition, dilatation, and position of the proximal and distal parts of an endograft in the descending thoracic aorta is feasible after TEVAR with the new software. Interobserver agreement for all measured parameters was excellent for the proximal and distal landing zones. The new method allows detection of subtle changes during follow-up. However, a larger study is needed to quantify how parameters change over time in complicated and uncomplicated TEVAR cases and to define the real added value of the new methodology.

Clinical Validation of a Semi-Automated Software for Maximal Diameter Measurements for Endovascular Repair Follow-up.

PURPOSE: To compare automated measurements of maximal diameter (Dmax) of abdominal aortic aneurysm (AAA) orthogonal to luminal or outer wall envelope centerline for endovascular repair (EVAR) follow-up. MATERIAL AND METHODS: Eighty-three consecutive patients with AAA treated by EVAR who had at least 1 computed tomography (CT) scan before and 2 CT scans after EVAR with at least 5 months' interval were included. Three-dimensional reconstruction of the AAA was achieved with dedicated segmentation software. Performances of automated calculation algorithms of Dmax perpendicular to lumen or outer wall envelope centerlines were then compared to manual measurement of Dmax on double-oblique multiplanar reconstruction (gold standard). Accuracy of automated Dmax measurements at baseline, follow-up, and progression over time was evaluated by calculation of mean error, Bland-Altman plot, and regression models. RESULTS: Disagreement in Dmax measurements between outer wall envelope algorithm and manual method was insignificant (mean error: baseline, -0.07 ± 1.66 mm, P = .7; first follow-up, 0.24 ± 1.69 mm, P = .2; last follow-up, -0.41 ± 2.74 mm, P = .17); whereas significant discrepancies were found between the luminal algorithm and the manual method (mean error: baseline, -1.24 ± 2.01 mm, P < .01; first follow-up, -1.49 ± 3.30 mm, P < .01; last follow-up, -1.78 ± 3.60 mm, P < .01). Dmax progression results were more accurate with AAA outer wall envelope algorithm compared to luminal method (P = .2). CONCLUSIONS: AAA outer wall envelope segmentation is recommended to enable automated calculation of Dmax perpendicular to its centerline during EVAR follow-up.

CompScore: Boosting Structure-Based Virtual Screening Performance by Incorporating Docking Scoring Function Components into Consensus Scoring.

Consensus scoring has become a commonly used strategy within structure-based virtual screening (VS) workflows with improved performance compared to those based in a single scoring function. However, no research has been devoted to analyze the worth of docking scoring functions components in consensus scoring. We implemented and tested a method that incorporates docking scoring functions components into the setting of high performance VS workflows. This method uses genetic algorithms for finding the combination of scoring components that maximizes the VS enrichment for any target. Our methodology was validated using a data set including ligands and decoys for 102 targets that have been widely used in VS validation studies. Results show that our approach outperforms other methods for all targets. It also boosts the initial enrichment performance of the traditional use of whole scoring functions in consensus scoring by an average of 45%. Our methodology showed to be outstandingly predictive when challenged to rescore external (previously unseen) data. Remarkably, CompScore was able not only to retain its performance after redocking with a different software, but also proved that the enrichment obtained was not artificial. CompScore is freely available at: http://bioquimio.udla.edu.ec/compscore/ .

U.S. Food and Drug Administration Precertification Pilot Program for Digital Health Software: Weighing the Benefits and Risks.

In 2017, the U.S. Food and Drug Administration (FDA) announced a new program for software classified as a medical device. The Digital Health Software Precertification (Pre-Cert) Program is designed to expedite regulatory review for companies that demonstrate quality and organizational excellence in software development. Although Pre-Cert is intended to promote the worthy goals of access and innovation in digital health, many questions have been raised. In particular, Pre-Cert may reduce incentives for developers to study the safety and effectiveness of their software products before patients start to rely on them. Although postmarket surveillance can mitigate risks of these products, the FDA does not have as much authority after a product's widespread use to enforce data collection deadlines. Pre-Cert may also create confusion for patients and physicians, who may believe that marketed products were subject to rigorous study.

A usability design checklist for Mobile electronic data capturing forms: the validation process.

BACKGROUND: New Specific Application Domain (SAD) heuristics or design principles are being developed to guide the design and evaluation of mobile applications in a bid to improve on the usability of these applications. This is because the existing heuristics are rather generic and are often unable to reveal a large number of mobile usability issues related to mobile specific interfaces and characteristics. Mobile Electronic Data Capturing Forms (MEDCFs) are one of such applications that are being used to collect health data particularly in hard to reach areas, but with a number of usability challenges especially when used in rural areas by semi literate users. Existing SAD design principles are often not used to evaluate mobile forms because their focus on features specific to data capture is minimal. In addition, some of these lists are extremely long rendering them difficult to use during the design and development of the mobile forms. The main aim of this study therefore was to generate a usability evaluation checklist that can be used to design and evaluate Mobile Electronic Data Capturing Forms in a bid to improve their usability. We also sought to compare the novice and expert developers' views regarding usability criteria. METHODS: We conducted a literature review in August 2016 using key words on articles and gray literature, and those with a focus on heuristics for mobile applications, user interface designs of mobile devices and web forms were eligible for review. The data bases included the ACM digital library, IEEE-Xplore and Google scholar. We had a total of 242 papers after removing duplicates and a total of 10 articles which met the criteria were finally reviewed. This review resulted in an initial usability evaluation checklist consisting of 125 questions that could be adopted for designing MEDCFs. The questions that handled the five main categories in data capture namely; form content, form layout, input type, error handling and form submission were considered. A validation study was conducted with both novice and expert developers using a validation tool in a bid to refine the checklist which was based on 5 criteria. The criteria for the validation included utility, clarity, question naming, categorization and measurability, with utility and measurability having a higher weight respectively. We then determined the proportion of participants who agreed (scored 4 or 5), disagreed (scored 1 or 2) and were neutral (scored 3) to a given criteria regarding a particular question for each of the experts and novice developers. Finally, we selected questions that had an average of 85% agreement (scored 4 or 5) across all the 5 criteria by both novice and expert developers. 'Agreement' stands for capturing the same views or sentiments about the perceived likeness of an evaluation question. RESULTS: The validation study reduced the initial 125 usability evaluation questions to 30 evaluation questions with the form layout category having the majority questions. Results from the validation showed higher levels of affirmativeness from the expert developers compared to those of the novice developers across the different criteria; however the general trend of agreement on relevance of usability questions was similar across all the criteria for the developers. The evaluation questions that were being validated were found to be useful, clear, properly named and categorized, however the measurability of the questions was found not to be satisfactory by both sets of developers. The developers attached great importance to the use of appropriate language and to the visibility of the help function, but in addition expert developers felt that indication of mandatory and optional fields coupled with the use of device information like the Global Positioning System (GPS) was equally important. And for both sets of developers, utility had the highest scores while measurability scored least. CONCLUSION: The generated checklist indicated the design features the software developers found necessary to improve the usability of mobile electronic data collection tools. In the future, we thus propose to test the effectiveness of the measure for suitability and performance based on this generated checklist, and test it on the end users (data collectors) with a purpose of picking their design requirements. Continuous testing with the end users will help refine the checklist to include only that which is most important in improving the data collectors' experience.

Validity and reliability of a novel optoelectronic device to measure movement velocity, force and power during the back squat exercise.

This study analysed the validity and reliability of a new optoelectronic device (Velowin) for the measurement of vertical displacement and velocity as well as to estimate force and mechanical power. Eleven trained males with Mean (SD) age = 27.4 (4.8) years, completed an incremental squat exercise test with 5 different loads (<30-90% of their 1-repetition maximum) while displacement and vertical velocity of the barbell were simultaneously measured using an integrated 3D system (3D motion capture system + force platform) and Velowin. Substantial to almost perfect correlation (concordance correlation coefficient = 0.75-0.96), root mean square error as coefficient of variation ±90% confidence interval ≤10% and good to excellent intraclass correlation coefficient = 0.84-0.99 were determined for all the variables. Passing and Bablock regression methods revealed no differences for average velocity. However, significant but consistent bias were determined for average or peak force and power while systematic and not proportional bias was found for displacement. In conclusion, Velowin, in holds of some potential advantages over traditionally used accelerometer or linear transducers, represents a valid and reliable alternative to monitor vertical displacement and velocity as well as to estimate average force and mechanical power during the squat exercise.

Validity of the "Samsung Health" application to measure steps: A study with two different samsung smartphones.

The purpose of this study was to examine the validity of a highly popular pedometer application (Samsung Health). Sixteen adults (28.8 ± 8.9 years of age) wore two Samsung smartphone models, Samsung Galaxy Core Prime (SGCP) and Samsung Galaxy S4 (SGS4), at three body locations (waist, arm, and hand) while walking and running over a 50-m test. All trials were recorded using a video as a gold standard measure of step counts. Results indicated that the validity of Samsung Health varied depending on the smartphone model, its body location, and the type of gait (walking and running). Samsung Health showed acceptable validity when the SGCP was located on the hand (Bias = -8.3%; RMSE = 5.6), and especially on the arm (Bias = -7.2%; RMSE = 4.9) while running, and when the SGS4 was located on the arm (Bias = -7.5%; RMSE = 5.4), and especially on the waist (Bias = 5.4%; RMSE = 3.7) while walking. Samsung Health only showed good validity when the SGS4 was located on the arm (Bias = 2.9%; RMSE = 3.6), and especially on the hand (Bias = 0.5%; RMSE = 2.5) while running. This application showed unacceptable validity in the remaining options.