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III STEP Series: Andrea L Behrman, Mark G Bowden, and Preeti M Nair Neuroplasticity After Spinal Cord Injury and Training: An Emerging Paradigm Shift in Rehabilitation and Walking Recovery PHYS THER 2006; 86: 1406-1425 [Abstract] [Full text] [PDF]

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Shift in Paradigm

Anton Wernig   (23 January 2007)

Shift in Paradigm 23 January 2007
Anton Wernig, clinical and basic research Dptm. Pysiology Univ. Bonn and Clinic KKL, Germany Send rapid response to journal: Re: Shift in Paradigm anton.wernig{at}ukb.uni-bonn.de Anton Wernig	Behrmann et al summarize(1) the evidence and rational for an ongoing paradigm shift in the treatment of people with incomplete spinal cord injury (SCI). In the general context of activity-related motor learning, rehabilitation of walking now focuses on intensive training of upright walking. Previously, isolated training of individual nonparalysed muscles prevailed, and walking was trained using long braces that enforced "unphysiological" gait and body weight support via arms and crutches. “Bring each patient to his limits by aggressive training of upright walking” (without orthoses) was our suggestion more than 15 years ago(2,3,4). After all, we “don’t exercise the piano if we want to learn to play the violin” was one of our slogans, highlighting context-specific learning in the damaged human spinal cord/central nervous system despite providing and obtaining reduced afferent and efferent information. One important mechanism particularly visible with severe paralysis needs to be added to the summary by Behrman et al: the involvement and entraining of motor programs. Maegele et al(5) documented that during attempts of complex movements like stepping (even air stepping or movements like bicycling in supine position), muscles can be activated that are not recruitable upon voluntary command (or magnetic field stimulation of the motor cortex[2,3,4]). The involvement of motor programs in achieving movements beyond voluntary controlled muscle activity apparently can be enormous, allowing independent ambulation over some tens of meters in patients in the nearly complete absence of voluntary muscle activity in defined resting positions (See patient Z [reference 3]). Although such profound involvement of motor programs has been rare in the more than 2,000 patients we have trained on a treadmill so far, some facilitation of walking by motor programs can frequently be noticed.(5) It is important to emphasize that proper afferent signals need to be provided for elicitation of facilitating motor programs: Derived from animal experiments (summarized in cited articles 1, 3, 4, 6, 7) we have termed them “rules of spinal locomotion” because they are active in spinal cats and, to some degree, in people with complete SCI.(3,4,8) These observations directly lead to a new approach in estimating the benefit of intensive locomotor training for the individual (also touched on by Behrman et al): Obviously, as recently suggested,(5) people with SCI who are non-ambulating need to be tested for useful motor programs evocable during locomotion on the treadmill. Behrman et al also perform the task of listing, comparing, and commenting on clinical trials in which locomotion training on a treadmill has been performed. In categorizing validity of the different trials according to the procedure for recruiting patients (“randomized” or not), and to the presence and definition of control groups (randomized among intervention and control groups; historic controls; no controls), remarkable curiosities occurred. Highest rank is given to a recent trial(9) in which training of locomotion on a treadmill is compared to equally intensive, though quite costly, therapists aiding locomotion over firm ground. When the 2 interventions are compared, there is no difference in the outcome (as one would expect from the study design, lest one attaches magic power to training on the treadmill). In both interventions, upright walking was trained with similar intensity.(10, 11) Nevertheless, in the absence of a control group that performed less- intensive upright walking (characteristic for “conventional” therapy), the authors(9) claim the superiority of intensive locomotor training (on the treadmill and over ground) over “conventional” therapy without showing this in their trial. Only when comparing their results with published (historic) data on the outcome of “conventional” therapy(9,10,11) does the difference become strikingly clear. In the given context, therefore, the trial needs to be rated V (no control) and certainly not I. In our controlled trials,(4) we used historic controls where randomization was warranted by including into the control or intervention group every patient who happened to enter our clinic during defined and adjacent periods of time and fulfilled the inclusion and exclusion criteria. Another important detail dealt with by Behrman et al deserves additional attention: speed of the moving band during training on the treadmill. Without evidence for a better or even comparable outcome, Dobkin et al(9) and others used speeds up to 3.6 km/h, which is much higher than we and others(2,3,4, 12) have suggested and successfully applied. Apart from less appropriate help applicable by the therapists at high speeds, the challenge on the physical capacity of the therapists and the number of therapists necessary for training a single patient--and thus the costs of the therapy--are considerably higher than at regular speeds. Finally, it is important to emphasize that once upright walking has been achieved by a patient as a consequence of intensive training in a clinical setting, this achievement is usually not lost in everyday living: In follow-up investigations 6 months to 6 years following discharge from the clinic, most of our patients maintained their skill(13); after all, walking is the best and also necessary training for maintenance and further improvement of walking. References: 1 Behrman AL, Bowden MG, Nair PM. Neuroplasticity after spinal cord injury and training: an emerging paradigm shift in rehabilitation and walking recovery. Phys Ther. 2006 Oct;86:1406-25. Review. 2 Wernig A, Müller S. Improvement of walking in spinal cord injured persons after treadmill training. In: Wernig A, ed. Plasticity of Motorneuronal Connections. Elsevier Science Publishers BV: Amsterdam, the Netherlands; 1991:475–485. 3 Wernig A, Müller S. Laufband locomotion with body weight support improved walking in persons with severe spinal cord injuries. Paraplegia. 1992;30:229-38. 4 Wernig A, Müller S, Nanassy A, Cagol E. Laufband therapy based on 'rules of spinal locomotion' is effective in spinal cord injured persons [published erratum in: Eur J Neurosci 1995;7:1429]. Eur J Neurosci 1995;7:823-9. 5 Maegele M, Müller S, Wernig A, Edgerton VR, Harkema SJ. Recruitment of spinal motor pools during voluntary movements versus stepping after human spinal cord injury. J Neurotrauma. 2002;19:1217-29. 6 Grillner S. Control of locomotion in bipeds, tetrapods and fish. In: Handbook of Physiology: The Nervous System II. Baltimore, Md: American Physiological Society; 1981:1179–1236. 7 Gossard JP, Hultborn H. The organization of the spinal rhythm generation in locomotion. In: Wernig A, ed. Plasticity and Motorneuronal Connections. Amsterdam, the Netherlands: Elsevier Science Publishers BV; 1991:385–404. 8 Harkema SJ, Hurley SL, Patel UK, et al. Human lumbosacral spinal cord interprets loading during stepping. J Neurophysiol. 1997;77:797–811. 9 Dobkin B, Apple D, Barbeau H, et al. Weight-supported treadmill vs over-ground training for walking after acute incomplete SCI. Neurology. 2006;66:484–493. 10 Wernig A. Treadmill training after spinal cord injury: good but not better. Neurology. 2006;67:1901; author reply 1901-1902. 11 Wernig A. Weight-supported treadmill vs over-ground training for walking after acute incomplete SCI. Neurology. 2006;67:1900; author reply 1900. 12 Norman KE, Pepin A, Ladouceur M, Barbeau H. A treadmill apparatus and harness support for evaluation and rehabilitation of gait. Arch Phys Med Rehabil. 1995;76:772-778. 13 Wernig A, Nanassy A, Müller S. Maintenance of locomotor abilities following Laufband (treadmill) therapy in para- and tetraplegic persons: follow-up studies. Spinal Cord. 1998:36;744-749.