PHYS THER
Vol. 88, No. 5, May 2008, pp. 594-595
DOI: 10.2522/ptj.20070315.ar
Author Response
Andrea L Behrman,
Preeti M Nair,
Mark G Bowden,
Robert C Dauser,
Benjamin R Herget,
Jennifer B Martin,
Chetan P Phadke,
Paul J Reier,
Claudia R Senesac,
Floyd J Thompson and
Dena R Howland
We thank Dr McEwen and Dr Edgerton for their thoughtful commentaries on our study.1 It is extremely helpful to receive input on our study of a child following spinal cord injury (SCI) and locomotor training (LT) from clinical and translational perspectives. The contrast between the 2 commentaries shows the striking differences that exist between the past and current cultures of general clinical thinking and the evolving science of rehabilitation and vision for the future. This investigation, among many others, exemplifies the important connection between the basic sciences and the clinic, in particular, the link between LT studies in cats and the human condition after SCI envisioned by Edgerton and others at least 15 years ago.2,3
As McEwen stated, "The change in the child's ability to walk, from being unable to stand or take a step to walking without assistance with a walker, is impressive." However, the impact of his ambulatory status on his ability to keep up with others, integrate socially, and participate in his environment is an important consideration identified by McEwen. An evaluation tool that she suggested to describe a child's activity and participation is the Pediatric Evaluation of Disability Inventory (PEDI). Although not reported in the article, this evaluation was done (Table). The overall score of interest for locomotion is the functional skills–mobility category score. Within this category, item scores changed from 0 (unable) before LT to 1 (capable) after LT. Specifically, improvements were noted in the following subcategories: indoor locomotion methods, indoor locomotion distance and speed, outdoor locomotion distance and speed, and outdoor locomotion surfaces. For caregiver-assisted mobility, a change was seen from total assistance before LT to supervision for indoor and outdoor locomotion and independent bed mobility and transfers after LT.
We agree with McEwen's comment that "qualitative information about the perceptions of the child and family also would [be] informative." Therefore, we asked the child's mother to provide a response to this and other points of interest raised by McEwen (mother's response). The mother's summary reflects the multiple benefits of walking even when performance does not meet age-matched norms. Thus, while examining outcomes relative to the norm is always an important consideration, perfection and normalcy are typically not reasonable goals after a central nervous system injury. The greater focus should be on the value of functional change that results in even incremental improvements in a person's quality of life. We believe more valid reference points are the child's performance level prior to training and his progress and benefit relative to nonambulatory children with SCI. Because the mother's summary is so illustrative, we will not comment further on this aspect.
One of the most common clinical approaches in the absence of active dorsiflexion is the use of ankle-foot orthoses (AFOs). In the current study, even though dorsiflexion was absent bilaterally (as shown by manual muscle testing), AFOs were not used during training because they were inconsistent with our theoretical approach. The intervention is designed to provide the most task-specific sensorimotor experience of walking throughout the step cycle during repetitive and intense practice. Use of currently available AFOs would disrupt limb kinematics, kinetics, muscle lengthening, and cutaneous and proprioceptive input. Repeated pressure on the tibialis anterior tendon was one of the essential cues to activate whole-leg flexion during the transition from stance to swing. Once voluntary stepping emerged, an AFO still was not used for the same reasons. If a "smarter" AFO were available that would provide an appropriate balance between foot clearance during swing and provision of appropriate sensory input, our choice may have shifted in the opposite direction. The child's improvement during training and at the 1-month follow-up suggest that the choice not to use currently available AFOs at these times was appropriate. For example, at the follow-up, he showed enhanced dorsiflexion during late swing, less disruptive leg crossing, and a larger step length. Due to the relatively short period that he had been walking and his continued recovery, we elected not to restrict potential ankle movement and loading in anticipation of further change. This approach is consistent with Edgerton's comment that "the spinal circuitry [can] take care of many of the details necessary to execute standing and stepping if this circuitry has not been allowed to ‘learn’ to become nonfunctional."
Each of Edgerton's points underscores issues that challenge current practice, highlight critical areas for ongoing inquiry, and present the foundation for future study. As he stated, we cannot assume that the current results will generalize to all children. However, it is critical to determine whether the lack of locomotor function is due to injury severity and associated neuromuscular impairments or to a lack of experience (training) that would promote recovery. Consistent with this perspective are our overall goals to identify a subpopulation of children with SCI who will benefit from intense LT and to determine the essential neural substrates underlying recovery of walking in this group. These goals provide the basis for our current "Kids STEP Study" supported by the Craig H Neilsen Foundation.
Although training begins in the clinic, we fully agree with Edgerton that once a critical level of function in standing and stepping is achieved, these activities become part of one's daily routine and the individual, in effect, continues task-specific training outside the clinic. The importance of the family's commitment to this continued training outside the clinical setting cannot be underestimated. We plan to follow this child until he is 18 years of age in order to more fully understand the long-term benefits of LT on this young subject's overall quality of life.
Overall, Edgerton's commentary captures the global relevance of the study for neuroplasticity and rehabilitation, and his vision compels us to not be confined by our current rehabilitation approaches or health care system.
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References
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- Behrman AL, Nair PM, Bowden MG, et al. Locomotor training restores walking in a nonambulatory child with chronic, severe, incomplete cervical spinal cord injury. Phys Ther. 2008;88:580–590.[Abstract/Free Full Text]
- Edgerton VR, Roy RR, Hodgson JA, et al. A physiological basis for the development of rehabilitative strategies for spinally injured patients. J Am Paraplegia Soc. 1991;14:150–157.[Medline]
- Barbeau H, Rossignol S. Enhancement of locomotor recovery following spinal cord injury. Curr Opin Neurol. 1994;7:517–724.[Web of Science][Medline]
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Copyright © 2008 by the American Physical Therapy Association.
