A case study with Symbihand: An sEMG-controlled electrohydraulic hand orthosis for individuals with Duchenne muscular dystrophy

Ronald A. Bos, Kostas Nizamis*, Bart F.J.M. Koopman, Just L. Herder, Massimo Sartori, Dick H. Plettenburg

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

20 Citations (Scopus)
68 Downloads (Pure)


With recent improvements in healthcare, individuals with Duchenne muscular dystrophy (DMD) have prolonged life expectancy, and it is therefore vital to preserve their independence. Hand function plays a central role in maintaining independence in daily living. This requires sufficient grip force and the ability to modulate it with no substantially added effort. Individuals with DMD have low residual grip force and its modulation is challenging and fatiguing. To assist their hand function, we developed a novel dynamic hand orthosis called SymbiHand, where the user's hand motor intention is decoded by means of surface electromyography, enabling the control of an electrohydraulic pump for actuation. Mechanical work is transported using hydraulic transmission and flexible structures to redirect interaction forces, enhancing comfort by minimizing shear forces. This paper outlines SymbiHand's design and control, and a case study with an individual with DMD. Results show that SymbiHand increased the participant's maximum grasping force from 2.4 to 8 N. During a grasping force-tracking task, muscular activation was decreased by more than 40% without compromising task performance. These results suggest that SymbiHand has the potential to decrease muscular activation and increase grasping force for individuals with DMD, adding to the hand a total mass of no more than 241 g. Changes in mass distributions and an active thumb support are necessary for improved usability, in addition to larger-scale studies for generalizing its assistive potential.

Original languageEnglish
Article number8926408
Pages (from-to)258-266
JournalIEEE Transactions on Neural Systems and Rehabilitation Engineering
Issue number1
Publication statusPublished - 2020


  • Daily assistance
  • duchenne muscular dystrophy
  • electrohydraulic
  • hand orthosis
  • sEMG control


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