title: The H2 robotic exoskeleton for gait rehabilitation after stroke: early findings from a clinical study.
abstract: BACKGROUND
  Stroke significantly affects thousands of individuals annually, leading to considerable physical impairment and functional disability. Gait is one of the most important activities of daily living affected in stroke survivors. Recent technological developments in powered robotics exoskeletons can create powerful adjunctive tools for rehabilitation and potentially accelerate functional recovery. Here, we present the development and evaluation of a novel lower limb robotic exoskeleton, namely H2 (Technaid S.L., Spain), for gait rehabilitation in stroke survivors.
  
  
  METHODS
  H2 has six actuated joints and is designed to allow intensive overground gait training. An assistive gait control algorithm was developed to create a force field along a desired trajectory, only applying torque when patients deviate from the prescribed movement pattern. The device was evaluated in 3 hemiparetic stroke patients across 4 weeks of training per individual (approximately 12 sessions). The study was approved by the Institutional Review Board at the University of Houston. The main objective of this initial pre-clinical study was to evaluate the safety and usability of the exoskeleton. A Likert scale was used to measure patient's perception about the easy of use of the device.
  
  
  RESULTS
  Three stroke patients completed the study. The training was well tolerated and no adverse events occurred. Early findings demonstrate that H2 appears to be safe and easy to use in the participants of this study. The overground training environment employed as a means to enhance active patient engagement proved to be challenging and exciting for patients. These results are promising and encourage future rehabilitation training with a larger cohort of patients.
  
  
  CONCLUSIONS
  The developed exoskeleton enables longitudinal overground training of walking in hemiparetic patients after stroke. The system is robust and safe when applied to assist a stroke patient performing an overground walking task. Such device opens the opportunity to study means to optimize a rehabilitation treatment that can be customized for individuals.
  
  
  BACKGROUND
  This study was registered at ClinicalTrials.gov ( https://clinicaltrials.gov/show/NCT02114450 ).
authors.affiliation: Neural Rehabilitation Group, Cajal Institute, Spanish Research Council, Av. Doctor Arce 37, Madrid, 28002, Spain. m.bortole@csic.es.|Noninvasive Brain-Machine Interface Systems Laboratory, Department of Electrical and Computer Engineering, University of Houston, Houston, 77204-4005, USA. m.bortole@csic.es.
authors.forename: Magdo
authors.initials: M
authors.lastname: Bortole
authors.affiliation: Noninvasive Brain-Machine Interface Systems Laboratory, Department of Electrical and Computer Engineering, University of Houston, Houston, 77204-4005, USA. avenkatakrishnan@uh.edu.|Currently at Palo Alto Research Center, a Xerox company, Palo Alto, CA 94304, USA. avenkatakrishnan@uh.edu.
authors.forename: Anusha
authors.initials: A
authors.lastname: Venkatakrishnan
authors.affiliation: Noninvasive Brain-Machine Interface Systems Laboratory, Department of Electrical and Computer Engineering, University of Houston, Houston, 77204-4005, USA. fzhu@uh.edu.
authors.forename: Fangshi
authors.initials: F
authors.lastname: Zhu
authors.affiliation: Neural Rehabilitation Group, Cajal Institute, Spanish Research Council, Av. Doctor Arce 37, Madrid, 28002, Spain. jc.moreno@csic.es.
authors.forename: Juan C
authors.initials: JC
authors.lastname: Moreno
authors.affiliation: TIRR Memorial Hermann and Department of PM&R, University of Texas Health Sciences Center, 1333 Moursund Street, Houston, 77030, USA. gerard.e.francisco@uth.tmc.edu.
authors.forename: Gerard E
authors.initials: GE
authors.lastname: Francisco
authors.affiliation: Neural Rehabilitation Group, Cajal Institute, Spanish Research Council, Av. Doctor Arce 37, Madrid, 28002, Spain. jose.pons@csic.es.
authors.forename: Jose L
authors.initials: JL
authors.lastname: Pons
authors.affiliation: Noninvasive Brain-Machine Interface Systems Laboratory, Department of Electrical and Computer Engineering, University of Houston, Houston, 77204-4005, USA. jlcontr2@central.uh.edu.
authors.forename: Jose L
authors.initials: JL
authors.lastname: Contreras-Vidal
mesh_terms: D000328:Adult; D000465:Algorithms; D001696:Biomechanical Phenomena; D000067190:Exoskeleton Device; D020233:Gait Disorders, Neurologic / Q000534:rehabilitation*; D006801:Humans; D035002:Lower Extremity; D008297:Male; D008875:Middle Aged; D010291:Paresis / Q000209:etiology / Q000534:rehabilitation; D061214:Patient Safety; D026741:Physical Therapy Modalities; D010865:Pilot Projects; D011474:Prosthesis Design; D012371:Robotics; D020521:Stroke / Q000150:complications; D000071939:Stroke Rehabilitation; D017741:Survivors; D016896:Treatment Outcome