Neuromuscular disorders typically limit motor function, resulting in a decrease in independence. A decrease in muscle strength directly affects physical function since it is needed to initiate movement, but joint contractures also limit physical function by impacting range of possible motion (ROM). In the COL6-related dystrophies (COL6-RDs) muscle weakness is compounded by significant progressive joint contractures. Although goniometry is the current standard for measuring ROM, previous studies using a 3D workspace have established clinically meaningful results. Comparisons between active and passive reachable spaces have not been performed, however.
We introduce the concept of “restorable” workspace, which we define as the 3D space that is determined by the difference between an individual’s active and passive reachable workspaces and symbolizes the area of therapeutic potential. The active reachable workspace represents an individual’s independent ROM, is determined by both muscle strength and joint contractures and is evaluated using a virtual reality game that encourages seated players to reach for items strategically placed superiorly, anteriorly, posteriorly and laterally to the position of the body at rest. The passive workspace represents an individual’s maximum ROM, is primarily determined by contractures and follows the same protocol completed by an evaluator. Data collection is via the HTC Vive and analyzed in MATLAB. We next plan to further evaluate intrarater and interrater variability and assess correlation with other validated measurements in individuals with COL6-RD.
Measuring “restorable” workspace would allow for a comparison of the effects of muscle strength and joint contractures on motor function, thus offering a functionally relevant marker of disease progression which could potentially serve as an outcome measure for assessing the efficacy of therapeutic interventions directed at restoring muscle strength in individuals with COL6-RD.