Original article| Volume 95, ISSUE 10, P1878-1887.e4, October 2014

Understanding Therapeutic Benefits of Overground Bionic Ambulation: Exploratory Case Series in Persons With Chronic, Complete Spinal Cord Injury



      To explore responses to overground bionic ambulation (OBA) training from an interdisciplinary perspective including key components of neuromuscular activation, exercise conditioning, mobility capacity, and neuropathic pain.


      Case series.


      Academic research center.


      Persons (N=3; 2 men, 1 woman) aged 26 to 38 years with complete spinal cord injury (SCI) (American Spinal Injury Association Impairment Scale grade A) between the levels of T1 and T10 for ≥1 year.


      OBA 3d/wk for 6 weeks.

      Main Outcome Measures

      To obtain a comprehensive understanding of responses to OBA, an array of measures were obtained while walking in the device, including walking speeds and distances, energy expenditure, exercise conditioning effects, and neuromuscular and cortical activity patterns. Changes in spasticity and pain severity related to OBA use were also assessed.


      With training, participants were able to achieve walking speeds and distances in the OBA device similar to those observed in persons with motor-incomplete SCI (10-m walk speed, .11–.33m/s; 2-min walk distance, 11–33m). The energy expenditure required for OBA was similar to walking in persons without disability (ie, 25%–41% of peak oxygen consumption). Subjects with lower soleus reflex excitability walked longer during training, but there was no change in the level or amount of muscle activity with training. There was no change in cortical activity patterns. Exercise conditioning effects were small or nonexistent. However, all participants reported an average reduction in pain severity over the study period ranging between −1.3 and 1.7 on a 0-to-6 numeric rating scale.


      OBA training improved mobility in the OBA device without significant changes in exercise conditioning or in neuromuscular or cortical activity. However, pain severity was reduced and no severe adverse events were encountered during training. OBA therefore opens the possibility to reduce the common consequences of chronic, complete SCI such as reduced functional mobility and neuropathic pain.


      List of abbreviations:

      EEG (electroencephalography), MG (medial gastrocnemius), MVC (maximal voluntary contraction), NRS (numeric rating scale), OBA (overground bionic ambulation), SCI (spinal cord injury), TEE (total energy expenditure), Vo2peak (peak oxygen consumption)
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        • Anderson K.D.
        Consideration of user priorities when developing neural prosthetics.
        J Neural Eng. 2009; 6: 055003
        • Brown-Triolo D.L.
        • Roach M.J.
        • Nelson K.
        • Triolo R.J.
        Consumer perspectives on mobility: implications for neuroprosthesis design.
        J Rehabil Res Dev. 2002; 39: 659-670
        • Widerstrom-Noga E.G.
        • Felipe-Cuervo E.
        • Broton J.G.
        • Duncan R.C.
        • Yezierski R.P.
        Perceived difficulty in dealing with consequences of spinal cord injury.
        Arch Phys Med Rehabil. 1999; 80: 580-586
        • Ditunno P.
        • Patrick M.
        • Stineman M.
        • Ditunno J.
        Who wants to walk? Preferences for recovery after SCI: a longitudinal and cross-sectional study.
        Spinal Cord. 2008; 46: 500-506
        • Farris R.J.
        Design of a powered lower-limb exoskeleton and control for gait assistance in paraplegics [dissertation].
        Vanderbilt University, Nashville2012
        • Burchiel K.J.
        • Hsu F.P.K.
        Pain and spasticity after spinal cord injury: mechanisms and treatment.
        Spine (Phila Pa 1976). 2001; 26: S146-S160
        • Widerstrom-Noga E.G.
        • Duncan R.
        • Felipe-Cuervo E.
        • Turk D.C.
        Assessment of the impact of pain and impairments associated with spinal cord injuries.
        Arch Phys Med Rehabil. 2002; 83: 395-404
        • Farris R.J.
        • Quintero H.A.
        • Goldfarb M.
        Performance evaluation of a lower limb exoskeleton for stair ascent and descent with paraplegia.
        Conf Proc IEEE Eng Med Biol Soc. 2012; 2012: 1908-1911
      1. Gancet J, Ilzkovitz M, Cheron G, et al. MINDWALKER: a brain controlled lower limbs exoskeleton for rehabilitation. Potential applications to space. 11th Symposium on Advanced Space Technologies in Robotics and Automation; European Space Agency's European Space Research and Technology Centre. Noordwijk, The Netherlands; April 12-14, 2011.

        • Contreras-Vidal J.L.
        • Presacco A.
        • Agashe H.
        • Paek A.
        Restoration of whole body movement: toward a noninvasive brain-machine interface system.
        IEEE Pulse. 2012; 3: 34-37
      2. Mohammed S, Amirat Y. In: Towards intelligent lower limb wearable robots: Challenges and perspectives-state of the art. IEEE International Conference on Robotics and Biomimetics (ROBIO 2008); 2008; Bangkok: IEEE; Feb 22-15, 2009. p 312–317.

        • Dollar A.M.
        • Herr H.
        Lower extremity exoskeletons and active orthoses: challenges and state-of-the-art.
        IEEE Trans Robot. 2008; 24: 144-158
      3. Tsukahara A, Hasegawa Y, Sankai Y. In: Gait support for complete spinal cord injury patient by synchronized leg-swing with HAL. 2011 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS); San Francisco: IEEE; Sep 25-30, 2011. p 1737–1742.

        • Zeilig G.
        • Weingarden H.
        • Zwecker M.
        • Dudkiewicz I.
        • Bloch A.
        • Esquenazi A.
        Safety and tolerance of the ReWalk exoskeleton suit for ambulation by people with complete spinal cord injury: a pilot study.
        J Spinal Cord Med. 2012; 35: 96-101
        • Esquenazi A.
        • Talaty M.
        • Packel A.
        • Saulino M.
        The ReWalk powered exoskeleton to restore ambulatory function to individuals with thoracic-level motor-complete spinal cord injury.
        Am J Phys Med Rehabil. 2012; 91: 911-921
        • Fineberg D.B.
        • Asselin P.
        • Harel N.Y.
        • et al.
        Vertical ground reaction force-based analysis of powered exoskeleton-assisted walking in persons with motor-complete paraplegia.
        J Spinal Cord Med. 2013; 36: 313-321
        • Talaty M.
        • Esquenazi A.
        • Briceno J.E.
        Differentiating ability in users of the ReWalk™ powered exoskeleton: an analysis of walking kinematics.
        IEEE Int Conf Rehabil Robot. 2013; 2013: 6650469
        • Jung J.Y.
        • Park H.
        • Yang H.D.
        • Chae M.
        Brief biomechanical analysis on the walking of spinal cord injury patients with a lower limb exoskeleton robot.
        IEEE Int Conf Rehabil Robot. 2013; 2013: 6650351
        • Bohannon R.W.
        • Smith M.B.
        Interrater reliability of a Modified Ashworth Scale of muscle spasticity.
        Phys Ther. 1987; 67: 206-207
      4. Strausser KA, Kazerooni H. In: The development and testing of a human machine interface for a mobile medical exoskeleton. 2011 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS); San Francisco: IEEE; Sep 25-30, 2011. p 4911–6.

      5. Strausser KA, Swift TA, Zoss AB, Kazerooni H, Bennett BC. In: Mobile exoskeleton for spinal cord injury: development and testing. Arlington: ASME; Oct 31-Nov 2, 2011. p 419–25.

        • Field-Fote E.C.
        • Roach K.E.
        Influence of a locomotor training approach on walking speed and distance in people with chronic spinal cord injury: a randomized clinical trial.
        Phys Ther. 2011; 91: 48-60
        • Benz E.N.
        • Hornby T.G.
        • Bode R.K.
        • Scheidt R.A.
        • Schmit B.D.
        A physiologically based clinical measure for spastic reflexes in spinal cord injury.
        Arch Phys Med Rehabil. 2005; 86: 52-59
        • Nakazawa K.
        • Kawashima N.
        • Akai M.
        Enhanced stretch reflex excitability of the soleus muscle in persons with incomplete rather than complete chronic spinal cord injury.
        Arch Phys Med Rehabil. 2006; 87: 71-75
        • Pierrot-Deseilligny E.
        • Burke D.
        The circuitry of the human spinal cord: its role in motor control and movement disorders.
        Cambridge University Pr, New York2005
        • Pfurtscheller G.
        • Brunner C.
        • Schlögl A.
        • Lopes S.F.H.
        Mu rhythm (de) synchronization and EEG single-trial classification of different motor imagery tasks.
        Neuroimage. 2006; 31: 153
        • Pfurtscheller G.
        • Leeb R.
        • Keinrath C.
        • et al.
        Walking from thought.
        Brain Res. 2006; 1071: 145-152
        • Barlow J.S.
        The electroencephalogram: its patterns and origins.
        MIT Pr, Cambridge1993
        • Wagner J.
        • Solis-Escalante T.
        • Grieshofer P.
        • Neuper C.
        • Müller-Putz G.
        • Scherer R.
        Level of participation in robotic-assisted treadmill walking modulates midline sensorimotor EEG rhythms in able-bodied subjects.
        Neuroimage. 2012; 63: 1203-1211
      6. Jacobs KA, Burns P, Kressler J, Nash MS. Heavy reliance on carbohydrate across a wide range of exercise intensities during voluntary arm ergometry in persons with paraplegia. J Spinal Cord Med 2013;36:427-35.

      7. Kressler J, Jacobs K, Burns P, Betancourt L, Nash M. Effects of circuit resistance training and timely protein supplementation on exercise-induced fat oxidation in tetraplegic adults. Top Spinal Cord Inj Rehabil 2014;20:113-22.

        • Widerstrom-Noga E.
        • Biering-Sorensen F.
        • Bryce T.
        • et al.
        The International Spinal Cord Injury Pain Basic Data Set.
        Spinal Cord. 2008; 46: 818-823
        • Bouhassira D.
        • Attal N.
        • Fermanian J.
        • et al.
        Development and validation of the neuropathic pain symptom inventory.
        Pain. 2004; 108: 248-257
        • Finnerup N.B.
        • Johannesen I.L.
        • Fuglsang-Frederiksen A.
        • Bach F.W.
        • Jensen T.S.
        Sensory function in spinal cord injury patients with and without central pain.
        Brain. 2003; 126: 57-70
        • Musselman K.E.
        Clinical significance testing in rehabilitation research: what, why, and how?.
        Phys Ther Rev. 2007; 12: 287-296
      8. American Electroencephalographic Society guidelines for standard electrode position nomenclature.
        J Clin Neurophysiol. 1991; 8: 200-202
        • Tudor-Locke C.
        • Bassett J.D.R.
        How many steps/day are enough? Preliminary pedometer indices for public health.
        Sports Med. 2004; 34: 1-8
        • Kressler J.
        • Nash
        • Burns P.A.
        • Field-Fote E.C.
        Metabolic responses to four different body weight supported locomotor training approaches in persons with incomplete spinal cord injury.
        Arch Phys Med Rehabil. 2013; 94: 1436-1442
        • Putzke J.D.
        • Richards J.S.
        • Hicken B.L.
        • DeVivo M.J.
        Predictors of life satisfaction: a spinal cord injury cohort study.
        Arch Phys Med Rehabil. 2002; 83: 555-561
        • Noreau L.
        • Shephard R.J.
        Spinal cord injury, exercise and quality of life.
        Sports Med. 1995; 20: 226-250
        • Swinnen E.
        • Duerinck S.
        • Baeyens J.P.
        • Meeusen R.
        • Kerckhofs E.
        Effectiveness of robot-assisted gait training in persons with spinal cord injury: a systematic review.
        J Rehabil Med. 2010; 42: 520-526
        • Thomas C.K.
        • Peterson L.
        • Ferrell S.
        • Cohan C.
        • Klein C.S.
        Daily use of leg muscles in healthy subjects.
        Med Sci Sports Exerc. 2010; 42: 25
        • Stephens M.J.
        • Yang J.F.
        Loading during the stance phase of walking in humans increases the extensor EMG amplitude but does not change the duration of the step cycle.
        Exp Brain Res. 1999; 124: 363-370
        • Thomas C.K.
        • Zijdewind I.
        Fatigue of muscles weakened by death of motoneurons.
        Muscle Nerve. 2006; 33: 21-41
        • Rayegani S.M.
        • Shojaee H.
        • Sedighipour L.
        • Soroush M.R.
        • Baghbani M.
        • Amirani O.B.
        The effect of electrical passive cycling on spasticity in war veterans with spinal cord injury.
        Front Neurol. 2011; 2: 39
        • Kiser T.S.
        • Reese N.B.
        • Maresh T.
        • et al.
        Use of a motorized bicycle exercise trainer to normalize frequency-dependent habituation of the H-reflex in spinal cord injury.
        J Spinal Cord Med. 2005; 28: 241-245
        • Browning R.C.
        • Kram R.
        Energetic cost and preferred speed of walking in obese vs. normal weight women.
        Obes Res. 2005; 13: 891-899
        • Schrack J.A.
        • Simonsick E.M.
        • Ferrucci L.
        The relationship of the energetic cost of slow walking and peak energy expenditure to gait speed in mid-to-late life.
        Am J Phys Med Rehabil. 2013; 92: 28-35
        • Garber C.E.
        • Blissmer B.
        • Deschenes M.R.
        • et al.
        American College of Sports Medicine position stand. Quantity and quality of exercise for developing and maintaining cardiorespiratory, musculoskeletal, and neuromotor fitness in apparently healthy adults: guidance for prescribing exercise.
        Med Sci Sports Exerc. 2011; 43: 1334-1359


        • Klein C.S.
        • Peterson L.B.
        • Ferrell S.
        • Thomas C.K.
        Sensitivity of 24-h EMG duration and intensity in the human vastus lateralis muscle to threshold changes.
        J Appl Physiol. 2010; 108: 655-661
        • Shah P.K.
        • Stevens J.E.
        • Gregory C.M.
        • et al.
        Lower-extremity muscle cross-sectional area after incomplete spinal cord injury.
        Arch Phys Med Rehabil. 2006; 87: 772-778
        • Makeig S.
        • Bell A.J.
        • Jung T.P.
        • Sejnowski T.J.
        Independent component analysis of electroencephalographic data.
        Adv Neural Inf Process Syst. 1996; 8: 145-151
        • Delorme A.
        • Sejnowski T.
        • Makeig S.
        Enhanced detection of artifacts in EEG data using higher-order statistics and independent component analysis.
        Neuroimage. 2007; 34: 1443
        • Nash M.S.
        • Mendez A.J.
        A guideline-driven assessment of need for cardiovascular disease risk intervention in persons with chronic paraplegia.
        Arch Phys Med Rehabil. 2007; 88: 751-757
        • Wallace T.M.
        • Levy J.C.
        • Matthews D.R.
        Use and abuse of HOMA modeling.
        Diabetes Care. 2004; 27: 1487-1495