On Placement, Location and Orientation of Wrist-Worn Tri-Axial Accelerometers during Free-Living Measurements

Abstract

Wearable accelerometers have recently become a standalone tool for the objective assessment of physical activity (PA). In free-living studies, accelerometers are placed by protocol on a pre-defined body location (e.g., non-dominant wrist). However, the protocol is not always followed, e.g., the sensor can be moved between wrists or reattached in a different orientation. Such protocol violations often result in PA miscalculation. We propose an approach, PLOE (“Placement, Location and Orientation Evaluation method”), to determine the sensor position using statistical features from the raw accelerometer measurements. We compare the estimated position with the study protocol and identify discrepancies. We apply PLOE to the measurements collected from 45 older adults who wore ActiGraph GT3X+ accelerometers on the left and right wrist for seven days. We found that 15.6% of participants who wore accelerometers violated the protocol for one or more days. The sensors were worn on the wrong hand during 6.9% of the days of simultaneous wearing of devices. During the periods of discrepancies, the daily PA was miscalculated by more than 20%. Our findings show that correct placement of the device has a significant effect on the PA estimates. These results demonstrate a need for the evaluation of sensor position.

Are Reallocations between Sedentary Behaviour and Physical Activity Associated with Better Sleep in Adults Aged 55+ Years? An Isotemporal Substitution Analysis

“…Accelerometry is considered the standard for objectively measuring SB, and has been shown to provide valid estimates of SB. Wrist-worn Actigraph accelerometers have been widely used for measuring PA, and have been shown to increase wear compliance in participants in free-living conditions [ 76 , 77 , 78 , 79 , 80 ]. In terms of sleep, we realize that polysomnography is considered the golden standard for measuring sleep objectively, providing detailed information about different sleep stages and sleep patterns [ 81 , 82 , 83 ].…”

The Use of Inertial Measurement Units for the Study of Free Living Environment Activity Assessment: A Literature Review

“…In addition to this, it is reported in one study [ 73 ] that the participants tend to prefer this configuration since sensors are more comfortable and less cumbersome to wear on the wrist. However, it is important to notice that another study [ 91 ] has shown that 15.6% of their participants who wore accelerometers on the wrist violated the protocol for one or more days. Sensors were worn on the wrong hand during 6.9% of the days and during the periods of discrepancies, the daily PA was miscalculated by more than 20%.…”

“…The last case observed mostly in FLEs situations is “complete freedom”. Participants are thus equipped with one or more IMUs and continue their daily and usual activities at home (including going to work, hobbies, and home activities) without any instruction or suggestion [ 6 , 7 , 17 , 27 , 38 , 39 , 44 , 60 , 69 , 72 , 73 , 74 , 75 , 80 , 89 , 91 , 100 , 104 , 104 ]. In the latter case, the participant is in the most natural conditions possible (both environment and activity).…”

“…Indeed, there are two types of environments: those that are familiar to the subject and those that are unfamiliar. Concerning articles using familiar environments, some studies in FLEs are limited to the habitats of the participants [ 6 , 17 , 27 , 37 , 38 , 41 , 69 , 72 , 73 , 79 , 80 , 83 , 84 , 91 ]. While others include all the environments frequented daily by the participant like library, gym, university, etc.…”

Highly Sensitive Signal Processing Devices for Capacitive Transducers of Micromechanical Accelerometers

“…Present-day micromechanical accelerometers are widely used in different types of transport and electronic means from aerospace, water and auto transport systems to mobile phones and new generation video game consoles [1][2][3][4][5][6]. There are many kinds of transducers in present micromechanical accelerometers, such as capacitive, piezo-resistive, electromagnetic, optical, thermal convective, acoustic waves resonant, field emission, tunnel transducers and so on [6].…”