Patients had to be able to walk independently and were not using oxygen therapy. Describe the walking track to the patient and then give the patient the following instructions6: The aim of this test is to walk as far as possible for 6 minutes. Accessibility Casanova C, Cote C, Marin JM, Pinto-Plata V, de Torres JP, Aguirre-Jame A, Vassaux C, Celli BR. During a test, the pulse oximeter produced artefactual values. In the studies by Capela et al [21,22], the reported maximum error in distance estimation was 2 m compared with our maximum of 23 m. We should point out, however, that the method described in those papers was only validated with 1 phone and with 15 tests, as compared with our 11 mobile phones and 49 tests. The discussion was audio-recorded for later analysis. Intelligent Respiratory Diagnostic Software Platform, Perfect for the general user and the most sophisticated labs, Breath-by-breath gas exchange & auto volume/gas calibrations, Learn how Vyaire is leading the fight against COVID-19, Standardize testing to the recommended American Thoracic Society (ATS) 6MWT protocol, because consistent testing yields consistent data for comparison, The patient wears a wireless Bluetooth wrist pulse oximeter that allows them to freely move through the course, untethered, Multiple oximetry sensors (finger, ear clip, forehead) come with each Vyntus WALK because not all patients are best-fit candidates for a finger probe, View real-time data graphically over time, or switch to the, Quality checks and built-in guidance throughout testing helps ensure the credibility of your data, Vyntus WALK can be run as a standalone device or the data can move in and out of SentrySuite software, Print standard report using WiFi direct to a printer or print via USB cable to printer, Store standard report on a network share drive as a PDF, Review data and add technician and physician comments, Trend data with past patient visits (also useful for treatment efficacy), Combine reporting with other tests, such as spirometry or diffusion testing. Capela NA, Lemaire ED, Baddour NC. The model includes 8 constructs: response efficacy, perceived ease of use, subjective norm, response cost, self-efficacy, perceived vulnerability, perceived severity, and intention to adopt. Proceedings of the International Conference on Bioinformatics, Computational Biology and Biomedical Informatics; BCB'13; September 22-25, 2013; Washington DC, USA. The outdoor algorithm is instead based on the assumption that the path walked by the user is straight or gently curved. Vitalograph offers this module when the COMPACT workstation is also provided for in-clinic use to capture other respiratory endpoints. To complement the observations made by the physiologist with these data, the mobile phone also had to be used during the test at the hospital. By using our services, you agree to the use of cookies. The algorithm uses the azimuth signal provided by Blackberry phones, which is, in turn, estimated from the gyroscope and the magnetometer sensors. Swipe back, and you are back to viewing graphically over time. Gali N, Hoeper MM, Humbert M, Torbicki A, Vachiery JL, Barbera JA, Beghetti M, Corris P, Gaine S, Gibbs JS, Gomez-Sanchez MA, Jondeau G, Klepetko W, Opitz C, Peacock A, Rubin L, Zellweger M, Simonneau G, ESC Committee for Practice Guidelines (CPG) Guidelines for the diagnosis and treatment of pulmonary hypertension: the task force for the diagnosis and treatment of pulmonary hypertension of the European Society of Cardiology (ESC) and the European Respiratory Society (ERS), endorsed by the International Society of Heart and Lung Transplantation (ISHLT). The selection_period parameter needs to be optimized. The test is easy to administer, well tolerated, and reflects activities of daily living better than other walk tests [2]. The minimum recommended length for a centre-based walking track is 25m and could be marked in metre increments. Patients need to get to the hospital clinic where the test is performed, sometimes from a long distance, with associated costs of transport and the accompanying stress for the patient. Introduction To Random Signal Analysis And Kalman Filtering. There is no need for multiple devices from several vendors with multiple user log-in credentials. Details about the algorithms are provided as follows. Federal government websites often end in .gov or .mil. The distance estimated in regular 6MWT clinics was collected 18 times from both male and female volunteers and with an age span of 15 to 85 years. The patient should rest for at least 15 minutes before beginning the 6MWT. In order to provide you with the best online experience this website uses cookies. The underlying concept is to detect changes of 180 in the mobile phone azimuth signal (an example of such a signal is shown is Figure 2). As for the min_turn_time, it is given an initial value of 10 seconds, and then adapted to the actual walking speed of the patient; each time a U-turn is detected, min_turn_time is updated to be the minimum observed time needed to complete a lap, minus 20%. When the test is performed outdoors, the weather can affect the patients performance. Is outdoor use of the six-minute walk test with a global positioning system in stroke patients' own neighbourhoods reproducible and valid? Q2. Patients identified scenarios for which they could perform the test while doing some other activity, for example, taking children to and from school. To account for this, the algorithm requires a simple calibration phase, in which users are asked to execute a 360 turn with the mobile phone in one hand, so that the minimum and maximum azimuths are captured. 6 minutes is a long time to walk, so you will be exerting yourself. This site uses cookies and similar technologies. One of the cardinal rules of a good 6MWT is to have the patient walk of their own volition. Please check with your local Vyaire representative. We included these algorithms in a mobile phone app, integrated with wireless pulse oximeters and a back-end server. PMC legacy view Most tests were executed by researchers in lab settings; however, to fine tune the indoor algorithm in real-life conditions, we also asked some patients to hold the mobile phone while performing the 6MWT during a regular clinic visit. Lab tests were undertaken by researchers, all males, aged 30, 33, and 37. https://creativecommons.org/licenses/by/4.0/, http://www.rcjournal.com/contents/08.03/08.03.0783.pdf, https://www.medicaljournals.se/jrm/content/abstract/10.2340/16501977-0881, http://www.mdpi.com/resolver?pii=s120202255, http://dx.plos.org/10.1371/journal.pone.0023080, https://experts.illinois.edu/en/publications/gaittrack-health-monitoring-of-body-motion-from-spatio-temporal-p, https://ieeexplore.ieee.org/abstract/document/6411040, https://ieeexplore.ieee.org/abstract/document/6943751, https://jneuroengrehab.biomedcentral.com/articles/10.1186/s12984-015-0013-9, http://europepmc.org/abstract/MED/26364278, http://europepmc.org/abstract/MED/31304343, https://researchinvolvement.biomedcentral.com/articles/10.1186/s40900-018-0102-6, https://www.researchgate.net/publication/287867125_Understanding_the_acceptance_of_mobile_health_services_A_comparison_and_integration_of_alternative_models, Walked distance measured by trundle wheel (m), mean (SD), Steps, as estimated by the phones pedometer, mean (SD), Standard deviation of the absolute difference (m). Because standardizing the complete testing process is critical to meaningful data for patient trending, Vyaire has integrated the complete ATS testing standards in the workflow-driven tablet software application. Careers, Reviewed by Jennifer Lynch and Qiyin Fang. When used with human beings, these systems are known to introduce some error because of the inherent noise that exists in the GPS system and the lower distances travelled [10-12]. Secondary measures can include fatigue and dyspnea, measured with a modified Borg or analogue scale and peripheral arterial oxygen saturation via pulse oximetry. At the end of the 6-min period, the patient is again invited to rest, while recovery heart rate and oxygen saturation are measured. Ata R, Gandhi N, Rasmussen H, El-Gabalawy O, Gutierrez S, Ahmad A, Suresh S, Ravi R, Rothenberg K, Aalami O. The endpoint is incorporated in Vitalograph Spirotrac software which manages subjects and gathers data from the devices used in the study. Rosenkranz S, Ghofrani HA, Grnig E, Klose H, Olschewski H, Hoeper MM. Patients can also send data about passive activity monitoring using HealthKit for iOS and Google Fit for Android. The approach was validated with 6 COPD patients and 6 healthy subjects performing a 6MWT. Do you see yourself using the app in the long term (2 years or more)? You are halfway., 4 min Keep up the good work. Predictive equation for males: 6MWD(m) = 867 (5.71 age, yrs) + (1.03 height, cm). Once SpO2%>/= 85% give the following encouragement (repeat this encouragement every 15 seconds if necessary). In the first part, 2 questions were asked to understand what the current limitations and needs were in relation to a conventional 6MWT: After a discussion of the answers to these 2 questions, a general presentation of the system was given (part 2), after which, other questions were asked about the overall concept (part 3): The fourth part of the discussion consisted in letting patients download the app on their phone and use it in a test run, while the research team recorded difficulties, technical issues, and general comments. The track should be flat, with minimal blind turns or obstacles. If the two tests are performed on the same day, at least 30 minutes rest should be allowed between tests. Monitor the patient for untoward signs and symptoms. 2012. Assessment of speed and position during human locomotion using nondifferential GPS. With regard to the indoor scenario, there is rich literature related to gait analysis with accelerometers [14-17]. 8600 Rockville Pike A comfortable ambient temperature and humidity should be maintained for all tests. Although the test is easy to perform, it involves costs and some practical limitations. It also requires a physiologist to observe the test and to note down the measurements. Normally the clinician does not walk with the patient during the test to avoid the problem of setting the walking pace. We developed 2 algorithms to compute the distance walked during a 6MWT using sensors embedded in a mobile phone. You are permitted to slow down, to stop, and to rest as necessary, but please resume walking as soon as you are able. The patient should remain in a clinical area for at least 15 minutes following an uncomplicated test. To mitigate these factors, the app displays clear instructions before each test is initiated. Quantified self and human movement: a review on the clinical impact of wearable sensing and feedback for gait analysis and intervention. The Web interface (Figure 6) allows physiologists and doctors to manage users, enter the results of a hospital 6MWT, review the data produced both by the app and hospital tests, and analyze trends for each patient. To understand user aspects such as the usability and technology acceptance of our system, we organized a discussion group to collaboratively analyze one of the first prototypes that had been developed. The test is also used for assessing the effect of therapies such as pulmonary rehabilitation, oxygen therapy, longterm use of inhaled corticosteroids, and lung volume reduction surgery [6]. NOTE! In this paper, we present a mobile phone app which enables patients to perform the 6MWT on their own, at their convenience or in the hospital setting, while augmenting the information collected during the test using off-the-shelf portable pulse oximeters. The .gov means its official. This is an open-access article distributed under the terms of the Creative Commons Attribution License (, GUID:1D91121F-54D4-4F9A-8BA1-322CD5EB8684, GUID:5D1229FA-8B1C-452C-8692-272EA48BC026. After this simple signal quality step, positioning samples start to be collected. From a validation against data recordings obtained from 17 subjects walking at different speeds, the authors found that the best performing algorithm was a support vector regression algorithm that was previously trained on an independent dataset recorded from 15 subjects who participated in 3 outdoor data collection activities. Measure the excess distance with a tape measure and tally up the total distance. Bethesda, MD 20894, Web Policies Patients are provided with a mobile phone app, downloaded onto their phones, which allows both indoor and outdoor 6MWT. For example, a perfectly still mobile phone will produce positioning samples with jitter around them because of noise, and the algorithm will sum up the distances between them. The six-minute walk test predicts peak oxygen uptake and survival in patients with advanced heart failure. The 6-min walk test (6MWT) is a common clinical instrument for assessing patients functional capacity. Understanding the acceptance of mobile health services: a comparison and integration of alternative models. Once U-turns are detected, the walked distance is computed by multiplying the number of U-turns by the length of the lap. As most algorithms used by GPS devices are proprietary, there is a lack of the literature describing how to derive the distance from the raw positions, except for the obvious computation of the distance between the first and the last received positions [12]. The characteristics of the outdoor tests are shown in Table 3. Owing to these limitations, the 6MWT cannot be performed very often. VYAIRE, the VYAIRE Logo and all other trademarks are property of VYAIRE MEDICAL, INC. By providing personal data to Vyaire, you acknowledge that you have read and understood the terms of our Privacy Statement.Our site also uses cookies to help us deliver our services. Patients struggled to log in, because complex passwords with capital and lower case letters were originally assigned to them. A faster sampling period will allow more samples to be used and therefore more noise to be accounted for in the distance estimation. This was because we hypothesized that users would prefer using the devices with which they are familiar; however, this meant that both Android and iPhones had to be supported. A longer period is problematic if the path walked by the user is not straight (in a perfectly straight path, in fact, just the first and the last sample would suffice). 2022 VYAIRE. Q7. Sorry, you need to enable JavaScript to visit this website. The other algorithm is meant to be used indoors and exploits the inertial sensors built into the phone to detect U-turns when patients walk back and forth along a corridor of fixed length. The algorithms implemented to estimate the distance walked from either the compass or GPS showed good agreement with the reference trundle wheel measurements, with errors below the clinically significant threshold. 897906. Both patients said that they would use the app regularly and would not need any help to do so. This number of seconds is then updated, every time a U-turn is detected, to half of min_turn_time, but capped at 5 seconds. The mean difference between the mobile phone-estimated distances and the reference values was 2.013 m (SD 7.84 m) for the indoor algorithm and 0.80 m (SD 18.56 m) for the outdoor algorithm. The tablet connects to the COMPACTTM Medical Workstation which then transmits the data to Vitalograph. Although we tried to simulate worst-case scenarios, it is possible that the distance estimation algorithm may perform worse in the wild. Shull PB, Jirattigalachote W, Hunt MA, Cutkosky MR, Delp SL. The 5 seconds value minimizes both mean and maximum error. Guideline 2014. Modern GPS receivers provide a signal which is the result of heavy processing and is usually improved and smoothed with well-known techniques [9]. We produce high quality, accurate and reliable, respiratory medical devices & services for primary, secondary healthcare and occupational health. National Library of Medicine For example, the indoor algorithm is based on the assumption that the azimuth signal is not very noisy, and it requires the user to hold the phone relatively still, which may be not always be the case for some users. The difference between the algorithms estimates and the measurements taken from the trundle wheel are summarized in Table 2, with the Bland-Altman plot shown in Figure 7. The characteristics of the tests are shown in Table 1. To structure the content of the discussion group, we used the mHealth technology acceptance model form [30], which integrates common technology acceptance and health behavior theories. The site is secure. Data were processed in both the time and frequency domains, and 8 gait parameters were extracted as the inputs to a support vector regression model to estimate gait speed. This site uses cookies to manage, improve and customize navigation. A total of 79 indoor and outdoor tests were performed. This may also be justified by the fact that they regularly used a mobile phone and, thus, were also highly self-efficient. The best distance walked in metres is recorded. Without a strict, standardized protocol, each technician could slightly vary how they run the test, what commands they give the patient, and the parameters they record, all of which can lead to variable data that delivers less-accurate data trends. The indoor test is performed on a walkway of a known length, for example, in a hospital clinic. Finally, in part 5, a further set of questions were asked about usability and acceptance: These questions were mapped to the constructs under analysis as follows: perceived ease of use: Q5, self-efficacy: Q7 and Q8, response cost: Q4, response efficacy: Q3, perceived vulnerability: Q1 and Q2, intention to adopt: Q9, Q10, and Q11. As a standalone device, users quickly enter patient demographics directly on the tablet PC, run the 6MWT, and print a standard report using one of two options: As a device connected to SentrySuite, users receive demographics from SentrySuite, run the 6MWT, and then return completed test data to SentrySuite. One exception is the fact that the maximum amplitude of the signal, on which the algorithm relies, may be less than 360. At the end of each test, the data are sent to the server to be reviewed by clinicians. Heart rate. At the commencement of PR, the 6MWT must be performed twice to account for a learning effect. Accuracy was calculated using the mean, median, and standard deviation of the difference between the reference values and the outputs from our algorithm; the mean, standard deviation, minimum and maximum of the absolute difference; and the Pearson correlation between estimated values and the reference values. Given that these patients can desaturate significantly during exertion, it was decided to acquire pulse oximetry data during the 6MWT with a wireless sensor attached to the patients finger. Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Old Road Campus Research Building, Oxford, OX3 7DQ, United Kingdom, Phone: 44 1865617679, cardiology, exercise test, pulmonary hypertension, mobile apps, digital signal processing, global positioning system. Vyntus WALK can be run as a standalone device generating a standard report, or the data can move in and out of SentrySuite software for a more robust interpretation and trending report. Comparing the trace with the underlying picture shows that the position is sometimes affected by an error, for example, near tall buildings which reflect the signal or because of trees obscuring the global positioning system satellites signal. With the advent of affordable digital devices and mobile phones, it becomes possible to perform the test in (or near) the patients home, using sensors such as accelerometers or the global positioning system (GPS) to estimate the distance walked. How does the test compare with your normal level of fitness; do the tests results adequately reflect the way you feel? The accuracy of the algorithm is reported separately for the indoor and outdoor scenarios. We tried to implement the algorithm described by Capela et al [22], but, possibly as we employed a different operating system, or possibly because of the lack of details in the paper, our implementation was not capable of detecting any U-turn. You have only 1 minute to go.. Patients performance might depend on their health status on that particular day and may not reflect their average status. The accuracy of the algorithms was estimated by performing a set of indoor and outdoor 6MWTs, with the app running on a mobile phone held in one hand and a trundle wheel held in the other hand. 2013. pp. Pulido T, Adzerikho I, Channick RN, Delcroix M, Gali N, Ghofrani H, Jansa P, Jing Z, Le Brun F, Mehta S, Mittelholzer CM, Perchenet L, Sastry B, Sitbon O, Souza R, Torbicki A, Zeng X, Rubin LJ, Simonneau G, SERAPHIN Investigators Macitentan and morbidity and mortality in pulmonary arterial hypertension. Having decided to use the patients own mobile phones, we needed to support both Android and iOS operating systems. For the indoor scenario, in a study by Schulte et al [20], an average absolute error of 4% was reported, as compared with our 0.02%. The minimum important difference (i.e. The system is both patient- and technician-friendly and because we know a single sensor does not fit all clinical needs, comes with an array of easy-to-wear sensors. The server system consists of a nonrelational database (ArangoDB), a REST API developed with Nodejs, and a front-end website developed with Angular. sharing sensitive information, make sure youre on a federal To this end, we made use of the virtual compass provided by the Android and iOS programming interfaces, which computes the azimuth by combining the signals provided by the accelerometer and the magnetometer. Solway S, Brooks D, Lacasse Y, Thomas S. A qualitative systematic overview of the measurement properties of functional walk tests used in the cardiorespiratory domain. From gait analysis, it is possible to compute the number of steps, which, once multiplied by the length of the step, would provide the distance walked. Vyntus WALK uses Bluetooth wireless pulse oximeter technology that allows the patient to move through the entire course and limits technician influence. We also assessed usability aspects related to the app in a discussion group with patients and clinicians using a technology acceptance model to guide discussion. Wevers LE, Kwakkel G, van de Port IG. In addition, Bland-Altman plots were also generated. In the interpretation of the results, a change in walking distance of more than 50 m is usually considered clinically significant in most disease states [6]. The new PMC design is here! The first seconds show the calibration phase, after which U-turns are detected when the difference between near angles becomes greater than the set threshold within a short time window. The discussion group was led by one researcher, who explained the system and its capabilities and asked the attendees questions. The research described in this paper was supported by the NIHR Biomedical Research Centre, Oxford, and by an EPSRC grant (EP/EP/N024966/1Intelligent Wearable Sensors for Predictive Patient Monitoring). During the test, the app also retrieves the local weather information from a Web-based service. If step counting is available, we use it to exclude samples for which the number of steps does not increase. The research team decided to recruit adults, without learning difficulties, who were familiar with mobile phones. If we compare our accuracy results with those reported in the literature, for the outdoor scenario, an average error of a few meters, up to a maximum of 20 m, was reported by Gray et al [10], which is consistent with our findings, although our maximum difference was higher. The outdoor 6MWT use-case is shown in Figure 5: the patient triggers a new test on the mobile phones home screen; the app shows suggestions on how to perform the test in the best conditions, then waits for the pulse oximeter to be connected, and records a baseline measurement of heart rate and oxygen saturation at rest. A patient performs the 6MWT outdoors, in a place of their choice. Proceedings of the 2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society; EMBC'14; August 26-30, 2014; Chicago, IL, USA. 1 min You are doing well. Overall, patients are stressed and rushed in hospital. If min_turn_time is such that the speed of the patient would be more than 2 m/s, it is capped. A total of 2 pulmonary hypertension patients, 1 cardiologist, 2 physiologists, and 1 nurse took part in the discussion group, where issues arising from the use of the 6MWT in hospital were identified. It includes 4 scenarios: (a) 6MWT at home, where patients perform a 6MWT in their home setting using their mobile phone with the app and a wireless pulse oximeter; (b) 6MWT in the hospital, where patients perform the test while being observed by a physician and with pulse oximetry data being collected through a tablet app; (c) activity tracking data retrieved by Google Fit or HealthKit transmitted for subsequent analysis; (d) data review performed by a physician through a Web interface. Gait analysisbased approaches have also been used for the 6MWT. Rasekaba T, Lee AL, Naughton MT, Williams TJ, Holland AE. A clinician reviews patients data on a website. Of these, we selected perceived ease of use, response cost, self-efficacy, response efficacy, perceived vulnerability, and intention to adopt as the most appropriate to our project and stage of development. A more sophisticated approach was taken by Capela et al [21,22]; they used a mobile phone app to count steps and identify when the user turns while walking back and forth along a corridor. NOTE! Once a sample has been selected, the distance between the previous selected sample and the newly selected one is computed and added to the total. Clinical validation of smartphone-based activity tracking in peripheral artery disease patients. What are the most annoying things about the 6MWT as it is done now? One engineer led the discussion, while the other took notes. By difference, we mean the difference between the estimated distance as computed by the app and the reference distance, as measured by the trundle wheel. Please note that: The equipment needed to conduct the 6MWT is outlined below: Instructions and encouragement must be standardised. and transmitted securely. The patient is then invited to walk for 6 min, during which the walked distance estimation and a timer are shown. Q1. Institute of Biomedical Engineering,