# Wearable Inertial Devices in Duchenne Muscular Dystrophy: A Scoping Review
## 3 Results  
Figure 1 schematizes the flowchart of the performed research. Based on the search string and after eliminating the duplicates, a total of 350 articles were found. Only research dealing with DMD in the human population and with the keyword \"Duchenne\" in the title, keywords, or abstract fields were considered, for a final result of 49 articles. All of these manuscripts were analyzed, with some excluded as they were not directly related to the use of IMU sensors for human movement investigation. No restrictions were imposed on the type of article. Finally, the full text of the remaining 23 research articles was examined and included in the qualitative and quantitative syntheses. Relevant data have been extracted from the selected articles. Papers were classified based on the IMU sensors' positioning on human body parts (Figure 2A). Three studies positioned the IMU on the chest; only one study proposed the positioning on the waist; regarding the upper limb, two studies positioned the IMUs on the forearm and seven studies on the wrist; as for the lower limb, two studies positioned the IMUs on the shanks and six studies on the ankles. Moreover, the articles were grouped considering the year of publication. Figure 2B shows that all articles were published after 2010, the majority after 2018. Only one article was published per year in 2011, 2012, 2015, and 2016, while in 2018 two articles were published and in 2020 there were three. Four manuscripts were registered for the year 2019; the years 2021 and 2022 saw 5 articles per year. Figure 1: Flowchart describing the several paper selection steps in the literature search. Finally, articles dealing with experimental tests were classified as differentiating ambulatory (15 articles) and non-ambulatory (10 articles) subjects, as reported in Figure 3. It must be noted that most of the studies enrolled both ambulatory and non-ambulatory patients, while only a few studies considered walking an inclusion/exclusion criterion. Several types of wearable inertial sensors were presented and used in the studies; Table 2 summarizes their main characteristics. All sensors present a 3-axis accelerometer to measure the segment acceleration in the 3D space, while only a few systems integrate a 3-axis gyroscope and a 3-axis magnetometer, which is fundamental for the analysis of segment orientation. Among these sensors, ActiMyo has been established as a Class I medical device for the continuous measurement of acceleration, velocity, and angular movements over prolonged periods in a domestic environment. In 2011, [PERSON] and colleagues [32] tested the accuracy and reliability of daily physical activity using a miniaturized wearable sensor during home monitoring. Experimental tests were conducted for two consecutive days and 5 DMD patients (age 4-6 years) were included in the study. Body movements and activities were monitored by a customized wearable sensor (ASUR-Autonomous Sensing Unit Recorder) composed of a 3D accelerometer and a 3D gyroscope. The unit was positioned on the chest of the patient. A customized algorithm for daily activity recognition (sitting, standing, laying, walking) was proposed and validated in a preliminary test. Moreover, as a second aim of the study, patients started prednisolone therapy and the experimental test was repeated after one month. Two types of objective parameters were considered and discussed: posture parameters, quantifying the percentage of time at rest, the percentage of time in motor activity, the percentage of time spent during specific daily activity, such as sitting, standing, lying down, and walking; and  
Figure 3: Experimental studies classification based on ambulatory and non-ambulatory patients. Figure 2: (**A**) Report of the different human body positions of the wearable inertial units described in the selected articles; (**B**) Classification of the articles based on the year of publication. walking parameters, quantifying common gait parameters (step, cadence, duration).