Longitudinal study of upper extremity reachable workspace in fascioscapulohumeral muscular dystrophy

Abstract

Facioscapulohumeral Dystrophy (FSHD) results in slowly progressive strength impairment, especially the upper extremities. Recent discoveries regarding pathophysiology have led to exciting novel therapeutic strategies. To further facilitate drug development, improved FSHD outcome measures that are functionally-relevant and sensitive to longitudinal change will be critical. Recently, a motion sensor (Kinect)-based upper extremity outcome called 'reachable workspace' that provides a quantitative reconstruction of an individual's reachability was developed. In this study, changes in reachable workspace were tracked upwards for 5-years in 18 FSHD subjects. Results show −1.63%/year decline in total reachable workspace (p=0.144); with most notable decline in the above-the-shoulder level quadrants (upper-lateral Q3: −9.5%/year, p<0.001 and upper-medial Q1: −6.8%/year, p=0.063) with no significant changes in the lower quadrants (Q2,Q4). Reachable workspace declined more significantly if the subjects were challenged with 500g wrist weights: total reachable workspace: −1.82%/year, p=0.039; Q1: −7.20%/year, p=0.041; Q3: −8.09%/year, p=0.001. Importantly, reachable workspace outcome was also able to distinguish subgroups in FSHD: mildlyand severely-affected with essentially unchanging reachability over years, and moderately-affected who demonstrate the most detectable changes longitudinally. The study demonstrates utility for measuring declines in upper quadrant

Motion sensor‐acquired reachable workspace correlates with patient‐reported upper extremity activities of daily living (ADL) function in facioscapulohumeral dystrophy

“…These results are important for a few reasons. First, the majority of our published work to date on the reachable workspace in FSHD has focused on its robustness in terms of reliability, validity, and sensitivity over time 4,5,10 . The current study adds important information regarding the reachable workspace, outside of its psychometric properties.…”

“…The 3D reachable workspace protocol followed previously published literature 3‐5 . Briefly, the subjects were seated in front of the Kinect2 sensor system (Microsoft corp., Redmond, WA, USA), and data were recorded while following video‐instructions of the movement protocol under the supervision of a study clinical evaluator (author V.C.).…”

“…The reachable workspace assessment tracks arm motion through standardized movements (that cover range of motion in various directions) using a depth sensor and, with the help of a computer software program, is able to reconstruct a hemispherical area of reachable space for each arm. Preliminary studies thus far in FSHD patients indicate that the reachable workspace measure (relative surface area, RSA) has excellent reliability, internal validity, and sensitivity in tracking changes longitudinally over the course of several years 4,5 …”

Reachable workspace analysis is a potential measurement for impairment of the upper extremity in neuralgic amyotrophy

“…The sample size was based on a power analysis for the primary outcome measure of the NA‐CONTROL study (ie, functional capacity of the upper extremity as measured with the Shoulder Rating Questionnaire‐‐‐Dutch language version [SRQ‐DLV]) 6 . Previous RWS studies in patients with neuromuscular disorders had similar or smaller sample sizes 7,10,12,16 . A detailed description of recruitment procedures and a full list of inclusion and exclusion criteria can be found in the design paper of the NA‐CONTROL study 6 …”

Technology outcome measures in neuromuscular disorders: A systematic review

“…Psychometric properties of Kinect-sensor RSA could be extracted in seven of nine studies (Table S4); content validity was established for FSHD, DMD, and ALS populations [38][39][40]; three studies explored the reliability in different NMDs, and five studies evaluated the sensitivity to change. In particular, two longitudinal studies assessed the sensitivity of RSA to track disease progression in FSHD and ALS populations, demonstrating slow changes in upper extremity function of FSHD and ALS patients in a time frame of 1 year [41,42].…”