# Wearable Inertial Devices in Duchenne Muscular Dystrophy: A Scoping Review
## 3 Results
A moderate correlation was obtained between 6 MWT and the average daily steps in JIA patients ([PERSON]'s rho(8) = 0.68). [PERSON] and colleagues [47] recruited 91 healthy volunteers (mean age = 16 years) for monitoring stride length, stride velocity, and walked distance per hour in different motion tasks (4-stair climb, 6 MWT, 10-m walk test, and rise from floor assessments) at baseline and 12 months later. Parameters were obtained from ActiMyo accelerometers worn at the wrist and ankle of participants. The aim of the study was to obtain normative data for validating the new outcome measures. Results pointed out significant positive correlations ([PERSON]'s rank correlation coefficient) of stride length with age and height of participants, and a significant increase in children's median stride length after the period. The 95 th centile stride velocity was not correlated with age and was unchanged after one year. [PERSON] and colleagues [48] wrote a review article discussing the potential effect of novel digital endpoints on the drug development standard for DMD patients. The study underlined that suitable and reliable objective endpoints calculated with wearable devices may decrease the time required to perform clinical assessment. Moreover, the comparison between objective and clinical data could provide support in the clinical decisions to continue, stop, or change the therapy. Finally, objective monitoring across different periods of time could quantify the change of outcomes at different stages of the disease. Similarly, [PERSON] et al. [49] proposed a systematic scoping review describing significant digital biomarkers for neuromuscular disorders. A total of 10 studies were included in the analysis. Observational studies included research on patients with amyotrophic lateral sclerosis, Duchenne muscular dystrophy, and spinal muscular atrophy. The review pointed to the potential use of digital biomarkers for several pathologies, the current initial stage of their analysis, and possible future investigations for the verification of digital biomarker effectiveness. In 2022, different studies on DMD patients were conducted. [PERSON] et al. [50] assessed 15 DMD patients at baseline and after 12 months in terms of body composition, isometric maximum voluntary contraction, plantar flexion, and physical activity. Daily physical activity was monitored using a tri-axial accelerometer (GENEActiv, Kimbolton, Cambs, United Kingdom). Accelerometric units were worn 24 h a day and continuously for 7 days on the participants' preferred wrist. Results pointed to significant changes in muscular strength, but no significant alteration of physical activity. [PERSON] et al. [51] investigated the correlation between imaging metrics from cardiac magnetic resonance imaging (CMR) and functional valuations, including quantitative muscle testing (QMT), spirometry, and accelerometry. A total of 49 patients with DMD were evaluated at different time intervals (baseline, after 1 year, after 2 years). DMD patients wore an Actigraph GT3X accelerometer (Actigraph, Pensacola, FL, USA) on their dominant wrist and ankle for 7 days, 24 h per day. Participants were classified as awake for their accelerometer recordings between 6:00 am and 9:00 pm. The physical activity outcomes obtained for the wrist and ankle accelerometers were: minutes per day of wearing an accelerometer (min/day wear), minutes per day of wearing and awake (min/day awake), vector magnitude generated while wearing (VM total), vector magnitude generated per minute while wearing (VM/min wear), and vector magnitude generated per minute while wearing and awake (VM/min awake). Among the results, the imaging of the upper extremity musculature showed the most robust and reliable correlations with accelerometry (Spearman's rho(49) > 0.5, \(p\) < 0.03). [PERSON] and colleagues [52] discussed the SV95C parameter as a new digital endpoint.