Validity of Multisensor Array for Measuring Energy Expenditure of an Activity Bout in Early Stroke Survivors

Hindawi Stroke Research and Treatment Volume 2018, Article ID 9134547, 8 pages https://doi.org/10.1155/2018/9134547 Research Article Validity of Multisensor Array for Measuring Energy Expenditure of an Activity Bout in Early Stroke Survivors Sharon Flora Kramer ,1,2 Liam Johnson,1,2,3 Julie Bernhardt,1,2 and Toby Cumming1,2 1 Stroke Division, Florey Department, The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC, Australia 2 NHMRC Centre of Research Excellence in Stroke Rehabilitation and Brain Recovery, The Florey Institute of Neuroscience and Mental Health, Melbourne, VIC, Australia 3 Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, VIC, Australia Correspondence should be addressed to Sharon Flora Kramer; Received 14 August 2017; Revised 4 January 2018; Accepted 22 January 2018; Published 7 March 2018 Academic Editor: David Vaudry Copyright © 2018 Sharon Flora Kramer et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Introduction. Stroke survivors use more energy than healthy people during activities such as walking, which has consequences for the way exercise is prescribed for stroke survivors. There is a need for wearable device that can validly measure energy expenditure (EE) of activity to inform exercise prescription early after stroke. We aimed to determine the validity and reliability of the SenseWear-Armband (SWA) to measure EE and step-counts during activity <1 month after stroke. Materials and Methods. EE was measured using the SWA and metabolic cart and steps-counts were measured using the SWA and direct observation. Based on walking ability, participants performed 2x six-minute walks or repeated sit-to-stands. Concurrent validity and test-retest reliability were determined by calculating intraclass and concordance correlation coefficients. Results and Discussion. Thirteen participants walked; nine performed sit-to-stands. Validity of the SWA measuring EE for both activities was poor (ICC/CCC < 0.40). The SWA overestimates EE during walking and underestimated EE during sit-to-stands. Test-retest agreement showed an ICC/CCC of <0.40 and >0.75 for walking and sit-to-stand, respectively. However, agreement levels changed with increasing EE levels (i.e., proportional bias). The SWA did not accurately measure step-counts. Conclusion. The SWA should be used with caution to measure EE of activity of mild to moderate stroke survivors <1 month after stroke. 1. Introduction Cardiorespiratory fitness levels are low early after stroke (i.e., <1 month since stroke onset), with fitness levels of stroke survivors ranging from 44% to 76% that of ageand sex-matched sedentary healthy adults [1–3]. In stroke survivors, exercising at a moderate intensity, progressing to high intensity can elicit a cardiorespiratory training effect leading to improved cardiorespiratory fitness [4]. Our recent systematic review results showed that walking is more effortful for stroke survivors compared to healthy controls based on energy expenditure (EE) levels; and in some stroke survivors slow walking equals moderate intensity activity [5], which could lead to improvements in cardiovascular fitness. Understanding the EE of activities can inform development of exercise interventions in stroke survivors. Indirect calorimetry using a metabolic cart is commonly used to measure the EE of physical activities. The metabolic cart measures the volume of oxygen uptake (VO2 ) using breath-by-breath analyses and has been shown to be a valid measure of VO2 uptake during different workloads in sedentary adults, moderately trained individuals, and athletes [6]. The development of mobile metabolic carts has extended the measurement from stationary activities (e.g., cycling on an ergometer or walking on a treadmill) to unfixed activities (e.g., overground walking). This more flexible method, while considered “gold standard,” remains cumbersome and costly and needs a trained staff member to operate the machine. It is 2 not readily usable in an acute clinical stroke setting. Sensorbased technology, including wearable devices, may be a lowcost, noninvasive, and broadly applicable tool to measure the EE of physical activity in the clinic early after stroke, provided it is valid and reliable. In a recent systematic review 60 different devices to measure physical activity in stroke were identified [7]. Of these devices, three had the potential to measure EE: the Actical (Koninklijke Philips NV), Body fixed sensor (Physilog, BioAGM), and the SenseWear Pro3 (Bodymedia Inc). The SenseWear (SWA) is worn on the upper arm and is the only multisensor device that includes accelerometer data as well as near body temperature, heat flux, and galvanic skin responses. Moore et al. showed that the SWA measure of daily EE, when worn on the unaffected arm (SWAunaffected ), was highly correlated with doubly labelled water (gold standard) in chronic stroke survivors (2473 ± 468 versus 2380 ± 551 kcal/day, resp.) [8]. EE during walking measured by the SWAunaffected showed good agreement (ICC > 0.70) and the SWAaffected showed fair agreement (ICC < 0.60) with a metabolic cart in chronic stroke survivors, suggesting that the SWA worn on the unaffected arm gives a more accurate estimate of EE during walking [9]. In the same study, the authors reported that the SWA step-count measures appear to be less promising [9]. It is unclear whether the easy-toapply SWA device is a reliable and valid marker of EE in those with acute stroke. We wanted to determine the validity and reliability of the SWAunaffected to measure EE during activity in people with acute stroke, that is, within the first month after stroke. This study is a part of a larger study in which we aimed to compare EE of acute stroke survivors to healthy controls. In this paper we will only discuss the result regarding the validity and reliability of the SWAunaffected . Using a mobile metabolic cart as a gold standard we sought to determine the concurrent validity and reliability of SWA measures of EE during a physical activity in stroke survivors whose stroke onset was less than 1 month ago. We hypothesised that the SWAunaffected is a valid and reliable tool to estimate EE during activity in acute stroke survivors. 2. Material and Methods 2.1. Participants. Stroke survivors admitted to the acute stroke ward at the Austin Hospital in Melbourne, Australia, were eligible to participate if they met the following criteria: (1) >18 years of age, (2) being within 1 month after stroke, (3) clinically diagnosed with stroke, (4) cognitively able to consent as assessed by the treating clinician, (5) sufficient English language command to follow complex instructions, and (6) medically cleared to participate by their treating clinician (...truncated)