Robot controlled, continuous passive movement of the ankle reduces spinal cord excitability in participants with spasticity: a pilot study
Date
2019
Authors
Noble, Steven
Pearcey, Gregory E. P.
Quartly, Caroline
Zehr, E. Paul
Journal Title
Journal ISSN
Volume Title
Publisher
Experimental Brain Research
Abstract
Spasticity of the ankle reduces quality of life by impeding walking and other activities of daily living. Robot-driven continuous
passive movement (CPM) is a strategy for lower limb spasticity management but effects on spasticity, walking ability
and spinal cord excitability (SCE) are unknown. The objectives of this experiment were to evaluate (1) acute changes in SCE
induced by 30 min of CPM at the ankle joint, in individuals without neurological impairment and those with lower limb
spasticity; and, (2) the effects of 6 weeks of CPM training on SCE, spasticity and walking ability in those with lower limb
spasticity. SCE was assessed using soleus Hoffmann (H-) reflexes, collected prior to and immediately after CPM for acute
assessments, whereas a multiple baseline repeated measures design assessed changes following 18 CPM sessions. Spasticity
and walking ability were assessed using the Modified Ashworth Scale, the 10 m Walk test, and the Timed Up and Go test.
Twenty-one neurologically intact and nine participants with spasticity (various neurological conditions) were recruited. In
the neurologically intact group, CPM caused bi-directional modulation of H-reflexes creating ‘facilitation’ and ‘suppression’
groups. In contrast, amongst participants with spasticity, acute CPM facilitated H-reflexes. After CPM training, H-reflex
excitability on both the more-affected and less-affected sides was reduced; on the more affected side H@Thres, H@50 and
H@100 all significantly decreased following CPM training by 96.5 ± 7.7%, 90.9 ± 9.2%, and 62.9 ± 21.1%, respectively. After
training there were modest improvements in walking and clinical measures of spasticity for some participants. We conclude
that CPM of the ankle can significantly alter SCE. The use of CPM in those with spasticity can provide a temporary period
of improved walking, but efficacy of treatment remains unknown.
Description
Keywords
Continuous passive movement, Spasticity, Spinal cord excitability, H-reflex, Rehabilitation Neuroscience Laboratory, Centre for Biomedical Research
Citation
Noble, S., Pearcey, G. E. P., Quartly, C., & Zehr, E. P. (2019) Robot controlled, continuous passive movement of the ankle reduces spinal cord excitability in participants with spasticity: A pilot study. Experimental Brain Research, 237(12). https://doi.org/10.1007/s00221-019-05662-4