Enzyme replacement therapy (ERT) and clinical trials for new therapies are available for LOPD, but muscle biopsy is often required to assess response.  There is a need for easily accessible, inexpensive and non-invasive outcome measures.  EIM meets these criteria and has been used in other neuromuscular disorders.

Five patients with genetically confirmed LOPD were asked to take home a hand-held EIM device (Chisel, Skulpt, Inc.).  This smart-phone sized device has incorporated, fixed electrodes and provides users with both a body fat measurement for each muscle assessed, as well as a Muscle Quality (MQ) score derived from raw EIM data. The MQ scale ranges from 0-100 with 100 being the best score possible.  Patients were instructed on how to use the device by a trained study coordinator and provided reference materials for home.  They were asked to make six weekly recordings of 6 muscles/muscle groups (deltoid, biceps brachii, triceps brachii, forearm flexors, vastus lateralis and anterior tibialis) for a total of 36 measurements per patient.  The results were then compared with clinician-performed measurements using the same device, taken at an office visit just preceding the home-based measures.

All five patients (4 females, 1 male) completed all 36 measurements unassisted.  No technical difficulties were reported.  There was no statistical difference between the clinician-measured and home measured values for either MQ (59.9 vs 54.7, p=0.39) or body fat percentage (24.73 vs 24.69, p=0.98) overall or for individual muscles. 

Patient-performed, hand-held EIM is a feasible means of recording and tracking muscle health.  Further study is required, but this technique holds promise for both clinical and research applications.