Biological Cybernetics

, Volume 112, Issue 5, pp 483–494 | Cite as

A planar neuro-musculoskeletal arm model in post-stroke patients

  • Mehran Asghari
  • Saeed BehzadipourEmail author
  • Ghorban Taghizadeh
Original Article


Mathematical modeling of the neuro-musculoskeletal system in healthy subjects has been pursued extensively. In post-stroke patients, however, such models are very primitive. Besides improving our general understanding of how stroke affects the limb motions, they can be used to evaluate rehabilitation strategies by computer simulations before clinical evaluations. A planar neuro-musculoskeletal arm model for post-stroke patients is developed. The main idea is to use a set of new coefficients, Muscle Significance Factors (MSF), to incorporate the effects of stroke in the muscle control performance. The model uses the optimal control theory to mimic the performance of the CNS and a two-link skeletal model with six muscles for the biomechanical part. The model was developed and evaluated using experimental data from six post-stroke patients with Brunnstrom levels of 4–6. The results show that MSFs are relatively distinct and independent from the arm motion which is used to determine their values. Its variation is in the range of 0–2.58% and decreases in higher Brunnstrom levels. The mean error of the model in predicting the path of motion varies from 0.9% in level 6 to 5.58% in level 4 subjects which can be considered a promising level of accuracy. Using the proposed model and the MSF to customize the model for each individual stroke patient seems a promising approach. It shows a reasonable level of robustness, i.e., independence from the type of motions and correlated with the severity of stroke, and accuracy in predicting the shape of the motion path.


Optimal control Musculoskeletal model CNS model of stroke patients Neuro-musculoskeletal arm model 



This work was partially supported financially by Iran National Science Foundation, under Grant Number 92042014.

Compliance with ethical standards

Ethical approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.

Informed consent

Informed consent was obtained from all individual participants included in the study.


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Mechanical Engineering DepartmentSharif University of TechnologyTehranIran
  2. 2.Djavad Mowafaghian Research Center in Neurorehabilitation TechnologiesTehranIran
  3. 3.Department of Occupational Therapy, School of Rehabilitation SciencesIran University of Medical SciencesTehranIran
  4. 4.Rehabilitation Research Center, School of Rehabilitation SciencesIran University of Medical SciencesTehranIran

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