Teknik och samhälle Datavetenskap och medieteknik Examensarbete 15 högskolepoäng, grundnivå Using Mobile Devices for Exercise Capacity Testing: An Implementation and Validation Study Att använda mobila enheter för kapacitetstestning: en implementation- och valideringsstudie Felix Morau Elin Forsnor Examen: Kandidatexamen 180 hp Handledare: Dario Salvi and Carl- Huvudområde: Data och Informationsveten- Magnus Olsson skap Examinator: Mia Persson Program: Informationsarkitekt Datum för slutseminarium: 2020-06-04 Abstract Mobile phones can be used to assess patients health by collecting valuable information through the sensors, GPS and accelerometers and then uploading them to a central database to allow for clinicians to remotely monitor the decline, improvement or over- all health status of a patient [1] [2]. Many mHealth applications use mobile phones built-in GPS, accelerometer and other sensors which allows for a large selection of work to compare the implemented exercise capacity test to [1]. The exercise capacity tests developed for this thesis is to be used in Mobistudy. Mobis- tudy is an open mobile-health platform for clinical research. The platform has an emphasis on regulatory compliance, patient consent and transparency [3]. The thesis resulted in the creation of two artifacts which were able to successfully collect data from the user to transfer to the clinicians using the application. During the analysis it was found that the SMWT algorithm developed by Salvi et al [4] worked well under non optimal conditions. The Queens College Step Tests result were in general poor, however more testing with more different phones is required to provide a clear answer. 0.1 Definitions mHealth: Mobile health involves sensors, mobile apps, social media, and location-tracking technology used in disease diagnosis, prevention, and management [2]. 6MWT: 6 Minute Walk Test, a test which measures a patients functional capacity, how the patient is responding to treatment and a prognosis across a range of chronic con- ditions [5]. Wearable Devices: Devices such as FitBits or Smartwatches which have the ability to collect bio-metrics from its user. Accelerometer: An instrument for measuring the acceleration of a moving or vibrat- ing body. VO2max: Maximal oxygen uptake that can be achieved despite increases in intensity of exercise [6]. Step Counting: Counting the number of steps a person walks/runs. Modal: A box which appears on top of the displayed current, usually darkens the background. NPM Package: A downloaded package created by someone else used in JavaScript. Contents 0.1 Definitions . 1 Introduction 1 1.1 Area of Concern . 1 1.2 mHealth Opportunities . 1 1.3 Exercise Capacity Testing . 1 1.3.1 Six Minute Walk Test . 2 1.3.2 Queens College Step Test . 2 1.4 Related Work . 2 1.5 Problem Definition . 3 1.6 Research Objective . 3 1.7 Context . 3 1.8 Research Approach . 4 1.9 Contribution . 4 1.10 Overview . 4 2 Method: Design Science Research 4 2.1 Problem Identification and Motivation . 5 2.2 Define the Objectives for a Solution . 6 2.3 Design and Development . 6 2.4 Demonstration . 6 2.4.1 Evaluation . 6 2.4.2 Communication . 6 2.4.3 Methodological Reflections and Study Limitations . 7 3 Results 7 3.1 Problem Identification . 7 3.2 Objectives of a Solution . 7 3.3 Design and Development . 8 3.3.1 Six Minute Walk Test . 11 3.3.2 Queens College Step Test . 13 3.4 Demonstration of Implementation . 15 4 Analysis 19 4.1 Evaluation of Six Minute Walk Test . 19 4.1.1 Data . 20 4.1.2 Data Analysis . 21 4.2 Evaluation of Queens College Step Test . 21 4.2.1 Data . 22 4.2.2 Data Analysis . 23 5 Discussion and Final Reflections 23 5.1 Positioning Our Results . 23 5.2 Practical Experiences and Design Choices . 24 5.3 Future Work . 24 5.4 Final Reflections . 25 References 27 1 Introduction 1.1 Area of Concern In February 2020, the number of smartphone users was 3.5 billion people, worldwide [7]. This increasing use of smartphones, together with the development of heart rate bands, smart watches and other wearable devices, has given rise to a large amount of user- generated data from day-to-day life. Effectively, this has opened up for today’s mobile phones to play a prominent role in modern healthcare [2] [8]. 1.2 mHealth Opportunities With a decrease in both price and size of sensors, mobile phones have become powerful yet ubiquitous monitoring systems within mobile health, or mHealth as it is popularly known [1]. mHealth services have the potential to be used for instance to encourage physical activity and healthy diets, monitoring asthma and various heart conditions. The widespread adoption of smartphones with powerful hardware often including bio-metric sensors and built-in GPS provides a useful platform for further service exploitation. In addition, people often carry their phones with them everywhere, and are used to their phones which also makes them a natural technology for self-monitoring tools as well [1]. This reduces the barriers for users to accept and adapt to the mHealth applications at hand, where the smartphone’s access to the internet further makes it possible to constantly send information about the patients bio-metrics to the physicians or researchers. Such bio- metric patient data can then be visualised and presented back to the patients directly on their phone. 1.3 Exercise Capacity Testing Within healthcare, exercise capacity testing is an integral component for monitoring changes in physical function of patients. Examples of tests include various oxygen con- sumption based tests such as cardiopulmonary exercise testing [9] and VO2max testing [6]. Cardiopulmonary tests are usually performed by patients with chronic heart and lung disease which makes it important for the patient to be able stop if they experience dizziness, chest-pains or other symptoms during the test [9]. Most cardiopulmonary exercise tests are static biking/running or step tests which measures functional status and capacity. These tests can be used to provide a means of monitoring response to treatment in patients with chronic disease [10]. VO2max tests show the highest rate at which oxygen can be taken in and utilised by the body. This measures the cardio-respiratory fitness and health of a person. It is used by both healthy and unhealthy people as a way to measure changes in aerobic capacity. The graded exercise test which measures VO2max requires the patient to be able to push themselves to absolute exhaustion and analysing the air. The test is very hard and expensive to administer and is challenging to run in real-world settings [6]. So called sub-maximal exercise testing, which are less problematic to run in practice, can be used a substitute to predict the VO2max. Sub-maximal tests using steps and walking 1 distance in a controlled (but easy to manage in practice) manner have been validated in terms of their capacity to estimate VO2max [6]. 1.3.1 Six Minute Walk Test The Six Minute Walk Test is an inexpensive, simple, safe, and generally accepted method for measuring the exercise capacity of patients with chronic heart/lung disease. The test should be used routinely in order to get a valid measurement of the patients aerobic capac- ity. The Six Minute Walk Tests performed by clinicians today are often conducted in clini- cal settings where the patients walks a predetermined path. These paths are often straight and the patients walk several laps over the course of the test [11] [12]. Research shows that the correlation between the Six Minute Walk Test and the estimation of VO2max is significant, which validates the Six Minute Walk Test as an effective way to predict the aerobic ability of patients and monitoring them to catch eventual regress/progress [11]. The measured variables in the Six Minute Walk Test are the distance walked during the test, symptoms, oxyhaemoglobin saturation and heart rate if possible. The distance a patient walks (6MWD = 6 Minute Walking Distance) is influenced by age, sex, height, weight, FEV and ethnicity [12] [9]. The first popular walk test was a twelve minute long test. Further development of the test has resulted in two new, shorter versions of the test, the Two Minute Walk Test and the Six Minute Walk Test, which today are the most widely used in the given field [10]. 1.3.2 Queens College Step Test The Queens College Step test is a paced step test designed around stepping up and down a step at a specific height. The test runs for a duration of three minutes where the step rate is set by a metronome. A significant correlation was found between the predicted and measured VO2Max which suggests that the Queens College Step Test is an adequate sub- stitute if exact V02max is not required. The Queens College Step Test is better suited for healthier participants [6]. One reason for using the Queens College Step Test on healthier subjects rather than on ill subjects is that the Queens College Step test is externally paced and exerts more stress on cardiorespiratory systems than the Six Minute Walk Test [13]. The Queens College Step Test has been previously used in studies relating to collecting VO2max data [14] [15] [13]. The Queens College Step Test and the Six Minute Walk Test have the same goal of collecting data relating to VO2Max but the results vary. One reason for this is that the Six Minute Walk Test is self paced while the Queens College Step Test is externally paced [13]. This means that the participant should aim to step using a four-step cadence, "up-up-down-down" for the duration of the test. The cadence is regulated by a metronome and is set at 88 bpm (22 steps) for women and 96 bpm (24 steps) for men [16].