Robot controlled, continuous passive movement of the ankle reduces spinal cord excitability in participants with spasticity: a pilot study

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.

Enhancement of spinal reciprocal inhibition depends on the movement speed and range of repetitive passive movement

“…In recent years, there has been a great deal of attention paid to research on enhancement methods of RI to inhibit excessive simultaneous activity and to inhibit the excitability of antagonist muscles (Fujiwara et al., 2011; Hirabayashi, Edama, Kojima, Miyaguchi, & Onishi, 2019; Jessop, DePaola, Casaletto, Englard, & Knikou, 2013; Kubota, Hirano, Morishita, Uehara, & Funase, 2015; Noble, Pearcey, Quartly, & Zehr, 2019; Perez, Field‐Fote, & Floeter, 2003; Ritzmann, Krause, Freyler, & Gollhofer, 2018; Roche, Lackmy, Achache, Bussel, & Katz, 2009, 2011; Yamaguchi et al., 2016, 2018). At our research institute, we have previously reported on the influence of repetitive passive movement (RPM) on the cerebral cortex, with RPM currently used widely as a rehabilitation technique (Miyaguchi et al., 2013; Sasaki et al., 2017, 2018).…”

Five Weeks of Yuishinkai Karate Training Improves Balance and Neuromuscular Function in Older Adults

“…Sphericity was assumed via Mauchly's Test (p > 0.05) and if not, degrees of freedom and p-value were corrected using the Greenhouse-Geisser method. When there were no differences between the pre-intervention results, an averaged pre-intervention value was compared to the post-intervention results using a paired t-test, as done in previous training studies [25][26][27]. The difference between post and baseline values were expressed as percent change from the pre-intervention results (%∆).…”

“…While the upright position is ideal for matching training conditions, group Ia presynaptic inhibition is modulated in this posture [49][50][51]. Since changes in re ex amplitude due to training in other work [27] shows Ia PSI as a mechanism of neuroplasticity, our choice of standing may have weakened our ability to detect change. Future work should include re ex measurement across a variety of tasks from sitting, standing, and walking [49] to better assess any changes in re ex excitability.…”

“…The karate sessions were delivered by black-belt instructors experienced in teaching martial arts in community-based settings. This "dosing" schedule was used to replicate both the approach taken in previous strength and locomotor interventions conducted in our laboratory [25][26][27][28][29][30] as well as to mimic the timing and delivery taken in other community-based martial arts programs [5,13,22,24]. Since rehabilitative applications often necessitate time e ciency, preference for a short duration for compliance and demonstration of e cacy was chosen.…”

“…M-wave and H-Re ex (M-H) recruitment curves of 40 stimulations were collected for each trial. These curves were used to determine the maximum action potential of the soleus muscle (M max ) amplitudes to normalize data [27].…”