Novel gait training alters functional brain connectivity during walking in chronic stroke patients: a randomized controlled pilot trial

Abstract

Background: A recent study has demonstrated that a turning-based treadmill program yields greater improvements in gait speed and temporal symmetry than regular treadmill training in chronic stroke patients. However, it remains unknown how this novel and challenging gait training shapes the cortico-cortical network and cortico-spinal network during walking in chronic stroke patients. The purpose of this study was to examine how a novel type of gait training, which is an unfamiliar but effective task for people with chronic stroke, enhances brain reorganization.

Methods: Subjects in the experimental and control groups received 30 min of turning-based treadmill training and regular treadmill training, respectively. Cortico-cortical connectivity and cortico-muscular connectivity during walking and gait performance were assessed before and after completing the 12-session training.

Results: Eighteen subjects (n = 9 per group) with a mean age of 52.5 ± 9.7 years and an overground walking speed of 0.61 ± 0.26 m/s consented and participated in this study. There were significant group by time interactions for gait speed, temporal gait symmetry, and cortico-cortical connectivity as well as cortico-muscular connectivity in walk-related frequency (24-40 Hz) over the frontal-central-parietal areas. Compared with the regular treadmill training, the turning-based treadmill training resulted in greater improvements in these measures. Moreover, the increases in cortico-cortical connectivity and cortico-muscular connectivity while walking were associated with improvements in temporal gait symmetry.

Conclusions: Our findings suggest this novel turning-based treadmill training is effective for enhancing brain functional reorganization underlying cortico-cortical and corticomuscular mechanisms and thus may result in gait improvement in people with chronic stroke.

Trial registration: ACTRN12617000190303 . Registered 3 February 2017, retrospectively registered.

Keywords: Brain connectivity; EEG; EMG; Gait; Stroke; Turning.

Fig. 1

The mean and standard variations of the EEG-EEG connectivity values in the gamma band are shown for the (a) MC-13 regions, (b) CFC-13 regions, and (c) IPC-13 regions. * denotes a significance level < 0.05 for intergroup comparisons (control vs. experimental)

Fig. 2

(a) Functional EEG-EEG connectivity in the gamma band with significant intergroup differences. The signals were recorded during regular treadmill walking. The lines represent the between-region connectivity. (b) Changes in functional EEG-EEG connectivity in the gamma band correlate with the recovery of temporal gait asymmetry. The solid lines represent the changes in the temporal asymmetry ratio that were negatively correlated with the changes in the EEG-EEG pairs. The dotted lines represent the changes in the temporal asymmetry ratio that were not correlated with the changes in the EEG-EEG pairs. For better visualization and interpretation, the left represents the contralesional hemisphere, and the right represents the ipsilesional hemisphere. The abbreviations of the cortical areas are listed in Table 1

Fig. 3

(a) Functional EEG-EMG connectivity in the gamma band. The signals were recorded during regular treadmill walking. The black circles represent the corticomuscular connectivity with significant intergroup difference. (b) The means and standard deviations of the EEG-EMG connectivity values are shown for the regions with significant intergroup differences. * denotes a significance level < 0.05 for intergroup comparisons (control vs. experimental). (c) Changes in the functional EEG-EMG connectivity in the gamma band correlate with the recovery of temporal gait asymmetry. The black circles represent the changes in the EEG-EMG pairs with significant intergroup differences that were negative correlated with the changes in the temporal asymmetry ratio. For better visualization and interpretation, the left represents the contralesional hemisphere, and the right represents the ipsilesional hemisphere

Fig. 4

(a) Functional EEG-EMG connectivity in the alpha band. The signals were recorded during regular treadmill walking. The black circles represent the corticomuscular connectivity with significant intergroup differences. (b) The means and standard deviations of the EEG-EMG connectivity values are shown for the regions with significant intergroup differences. * denotes a significance level < 0.05 for intergroup comparisons (control vs. experimental). (c) Changes in the functional EEG-EMG connectivity in the alpha band correlate with the recovery of temporal gait asymmetry. The black circles represent the changes in the EEG-EMG pairs with significant intergroup differences that negatively correlate to the changes in the temporal asymmetry ratio. The gray circles represent the changes in the EEG-EMG pairs with significant intergroup differences that do not correlate to the changes in the temporal asymmetry ratio. For better visualization and interpretation, the left represents the contralesional hemisphere, and the right represents the ipsilesional hemisphere