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Reducing Circumduction and Hip Hiking During Hemiparetic Walking Through Targeted Assistance of the Paretic Limb Using a Soft Robotic Exosuit

Awad, Louis N. PT, DPT, PhD; Bae, Jaehyun MS; Kudzia, Pawel MS; Long, Andrew PhD; Hendron, Kathryn PT, DPT; Holt, Kenneth G. PT, PhD; O'Donnell, Kathleen MID; Ellis, Terry D. PT, PhD; Walsh, Conor J. PhD

American Journal of Physical Medicine & Rehabilitation: October 2017 - Volume 96 - Issue 10 - p S157–S164
doi: 10.1097/PHM.0000000000000800

Objective: The aim of the study was to evaluate the effects on common poststroke gait compensations of a soft wearable robot (exosuit) designed to assist the paretic limb during hemiparetic walking.

Design: A single-session study of eight individuals in the chronic phase of stroke recovery was conducted. Two testing conditions were compared: walking with the exosuit powered versus walking with the exosuit unpowered. Each condition was 8 minutes in duration.

Results: Compared with walking with the exosuit unpowered, walking with the exosuit powered resulted in reductions in hip hiking (27 [6%], P = 0.004) and circumduction (20 [5%], P = 0.004). A relationship between changes in knee flexion and changes in hip hiking was observed (Pearson r = −0.913, P < 0.001). Similarly, multivariate regression revealed that changes in knee flexion (β = −0.912, P = 0.007), but not ankle dorsiflexion (β = −0.194, P = 0.341), independently predicted changes in hip hiking (R2 = 0.87, F(2, 4) = 13.48, P = 0.017).

Conclusions: Exosuit assistance of the paretic limb during walking produces immediate changes in the kinematic strategy used to advance the paretic limb. Future work is necessary to determine how exosuit-induced reductions in paretic hip hiking and circumduction during gait training could be leveraged to facilitate more normal walking behavior during unassisted walking.

From the Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts (LNA, JB, PK, AL, KO, CJW); Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts (LNA, JB, AL, CJW); and Department of Physical Therapy and Athletic Training, Boston University, Boston, Massachusetts (LNA, KH, KGH, TDE).

All correspondence and requests for reprints should be addressed to: Conor J. Walsh, PhD, John A. Paulson School of Engineering and Applied Sciences, Harvard University, 60 Oxford St, Suite 403, Cambridge, MA 02138; or Terry D. Ellis, PT, PhD, Department of Physical Therapy and Athletic Training, Boston University, 635 Commonwealth Ave, 6th Floor, Boston, MA 02215.

JB and PK contributed equally.

This work was supported by the Defense Advanced Research Projects Agency, Warrior Web Program (Contract Number W911NF-14-C-0051). This work was also partially funded by the National Science Foundation (CNS-1446464), American Heart Association (15POST25090068), National Institutes of Health (1KL2TR001411), Harvard University Star Family Challenge, Rolex Award for Enterprise, Wyss Institute for Biologically Inspired Engineering, and Harvard John A. Paulson School of Engineering and Applied Sciences.

The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressly or implied, of Defense Advanced Research Projects Agency or the US Government. Patents have been filed with the US Patent Office describing the exosuit components documented in this article. JB, KGH, KO, and CJW were authors of those patents and patent applications. Harvard has entered into a licensing and collaboration agreement with ReWalk Robotics. CJW is a paid consultant for ReWalk Robotics.

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