A dedicated electrical impedance myography device in the assessment of Duchenne muscular dystrophy. (P5.102)

Objective: To evaluate the sensitivity to disease progression of Duchenne muscular dystrophy (DMD) of a dedicated electrical impedance myography (EIM) device. Background: Recent work in DMD has shown that EIM is sensitive to disease progression and the therapeutic benefit of corticosteroids. Most work to date has used custom-designed, off-the-shelf impedance devices and has been performed at a single center. Here we evaluate a dedicated EIM system that allows for rapid and improved data acquisition. Design/Methods: In this 4-center study, healthy boys and those with DMD were assessed at 0, 3, 6 and 12 months after enrollment. The EIM 1103 System (Skulpt, Inc) was utilized with measurements performed on the dominant side on the deltoid, biceps brachii, wrist extensors, wrist flexors, vastus lateralis, tibialis anterior, and medial gastrocnemius. Multifrequency impedance data from 1kHz to 1MHz were collected on each muscle. Subjects in the 3–12-year-old group also underwent functional testing. A linear mixed effect model was applied, with random intercepts and slopes, alpha=0.05, 2-tailed for all analyses. Results: Seventy-one boys with DMD and 72 healthy controls, mean age 8.2 years (range 0.6–17.4 years) and 8.3 years (range 0.3–17.9 years), respectively, were enrolled. A variety of multifrequency EIM measures demonstrated differences in the longitudinal EIM parameters over time in both younger and older boys. For example, the previously reported 100–500 kHz phase slope parameter averaged across all 7 muscles was reduced (−0.0563 (standard error 0.0164)) in boys with DMD compared to controls (p=0.0009) at 12 months. Utilizing this measure as an outcome in a 12-month clinical trial would require a sample size of just 19 subjects/arm assuming an effect size of 1.0. Conclusions: EIM multifrequency parameters obtained with this dedicated system are sensitive to disease progression in DMD. Further analysis of the EIM data and its relationship to the simultaneously obtained functional measures is underway. Study Supported by: Grant 2R44NS073188 from the National Institutes of Health Disclosure: Dr. Zaidman has nothing to disclose. Dr. Rutkove holds stock and/or stock options in Skulpt, Inc. Dr. Florence has received personal compensation for activities with GSK/Prosena and DART Therapeutics as a consultant. Dr. Connolly has received personal compensation for activities with Catabasis, Sarepta, BMSquibb, Fibrogen Therapeutics, Cytokinetics, Avexis, and Bamboo. Dr. Connolly has received research support from PTC Therapeutics, Serapta Therapeutics, Lilly, Fibrogen, Cytokinetics, Ionis, ISIS, Halo Therapeutics Dr. Wong has received personal compensation for market research in pediatric neuromuscular disorders. Dr. Yang has nothing to disclose. Dr. Darras has received personal compensation for activities with UpToDate, Inc., Isis Pharmaceuticals, Inc, and Athena Diagnostics. Dr. Kapur has nothing to disclose. Dr. Bohorquez has received compensation for serving as the CEO of Skulpt, Inc.