Superficial Shoulder Muscle Synergy Analysis in Facioscapulohumeral Dystrophy During Humeral Elevation Tasks

Johannes Maria Nicolaas Essers*, Anneliek Peters, Kenneth Meijer, Koen Peters, Alessio Murgia

*Corresponding author for this work

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Facioscapulohumeral dystrophy (FSHD) is a progressive muscle-wasting disease which leads to a decline in upper extremity functionality. Although the scapulohumeral joint's stability and functionality are affected, evidence on the synergetic control of the shoulder muscles in FSHD individuals is still lacking. The aim of this paper is to understand the neuromuscular changes in shoulder muscle control in people with FSHD. Upper arm kinematics and electromyograms (EMG) of eight upper extremity muscles were recorded during shoulder abduction-adduction and flexion-extension tasks in eleven participants with FSHD and 11 healthy participants. Normalized muscle activities were extracted from EMG signals. Non-negative matrix factorization was used to compute muscle synergies. Maximum muscle activities were compared using non-parametric analysis of variance. Similarities between synergies were also calculated using correlation. The Biceps Brachii was significantly more active in the FSHD group (25 +/- 2%) while Trapezius Ascendens and Serratus Anterior were less active (32 +/- 7% and 39 +/- 4%, respectively). Muscle synergy weights were altered in FSHD individuals and showed greater diversity while controls mostly used one synergy for both tasks. The decreased activity by selected scapula rotator muscles and muscle synergy weight alterations show that neuromuscular control of the scapulohumeral joint is less consistent in people with FSHD compared to healthy participants. Assessments of muscle coordination strategies can be used to evaluate motor output variability and assist in management of the disease.

Original languageEnglish
Pages (from-to)1556-1565
Number of pages10
JournalIeee Transactions on Neural Systems and Rehabilitation Engineering
Issue number8
Publication statusPublished - Aug 2019


  • FSHD
  • humeral elevation
  • motor control
  • muscular dystrophy
  • muscle synergies
  • scapula rotation

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