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Zipser-Mohammadzada F, Scheffers MF, Conway BA, Halliday DM, Zipser CM, Curt A, Schubert M. Intramuscular coherence enables robust assessment of modulated supra-spinal input in human gait: an inter-dependence study of visual task and walking speed. Exp Brain Res 2023; 241:1675-1689. [PMID: 37199775 DOI: 10.1007/s00221-023-06635-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Accepted: 05/11/2023] [Indexed: 05/19/2023]
Abstract
Intramuscular high-frequency coherence is increased during visually guided treadmill walking as a consequence of increased supra-spinal input. The influence of walking speed on intramuscular coherence and its inter-trial reproducibility need to be established before adoption as a functional gait assessment tool in clinical settings. Here, fifteen healthy controls performed a normal and a target walking task on a treadmill at various speeds (0.3 m/s, 0.5 m/s, 0.9 m/s, and preferred) during two sessions. Intramuscular coherence was calculated between two surface EMG recordings sites of the Tibialis anterior muscle during the swing phase of walking. The results were averaged across low-frequency (5-14 Hz) and high-frequency (15-55 Hz) bands. The effect of speed, task, and time on mean coherence was assessed using three-way repeated measures ANOVA. Reliability and agreement were calculated with the intra-class correlation coefficient and Bland-Altman method, respectively. Intramuscular coherence during target walking was significantly higher than during normal walking across all walking speeds in the high-frequency band as obtained by the three-way repeated measures ANOVA. Interaction effects between task and speed were found for the low- and high-frequency bands, suggesting that task-dependent differences increase at higher walking speeds. Reliability of intramuscular coherence was moderate to excellent for most normal and target walking tasks in all frequency bands. This study confirms previous reports of increased intramuscular coherence during target walking, while providing first evidence for reproducibility and robustness of this measure as a requirement to investigate supra-spinal input.Trial registration Registry number/ClinicalTrials.gov Identifier: NCT03343132, date of registration 2017/11/17.
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Affiliation(s)
| | - Marjelle Fredie Scheffers
- Department of Neurophysiology, Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
- Faculty of Medicine, Utrecht University, Utrecht, The Netherlands
| | - Bernard A Conway
- Biomedical Engineering, University of Strathclyde, Glasgow, G4 0NW, UK
| | - David M Halliday
- School of Physics, Engineering and Technology, University of York, York, YO10 5DD, UK
- York Biomedical Research Institute, University of York, York, UK
| | - Carl Moritz Zipser
- Department of Neurophysiology, Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
| | - Armin Curt
- Department of Neurophysiology, Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
| | - Martin Schubert
- Department of Neurophysiology, Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
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Zipser-Mohammadzada F, Conway BA, Halliday DM, Zipser CM, Easthope CA, Curt A, Schubert M. Intramuscular coherence during challenging walking in incomplete spinal cord injury: Reduced high-frequency coherence reflects impaired supra-spinal control. Front Hum Neurosci 2022; 16:927704. [PMID: 35992941 PMCID: PMC9387543 DOI: 10.3389/fnhum.2022.927704] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Accepted: 07/15/2022] [Indexed: 11/30/2022] Open
Abstract
Individuals regaining reliable day-to-day walking function after incomplete spinal cord injury (iSCI) report persisting unsteadiness when confronted with walking challenges. However, quantifiable measures of walking capacity lack the sensitivity to reveal underlying impairments of supra-spinal locomotor control. This study investigates the relationship between intramuscular coherence and corticospinal dynamic balance control during a visually guided Target walking treadmill task. In thirteen individuals with iSCI and 24 controls, intramuscular coherence and cumulant densities were estimated from pairs of Tibialis anterior surface EMG recordings during normal treadmill walking and a Target walking task. The approximate center of mass was calculated from pelvis markers. Spearman rank correlations were performed to evaluate the relationship between intramuscular coherence, clinical parameters, and center of mass parameters. In controls, we found that the Target walking task results in increased high-frequency (21–44 Hz) intramuscular coherence, which negatively related to changes in the center of mass movement, whereas this modulation was largely reduced in individuals with iSCI. The impaired modulation of high-frequency intramuscular coherence during the Target walking task correlated with neurophysiological and functional readouts, such as motor-evoked potential amplitude and outdoor mobility score, as well as center of mass trajectory length. The Target walking effect, the difference between Target and Normal walking intramuscular coherence, was significantly higher in controls than in individuals with iSCI [F(1.0,35.0) = 13.042, p < 0.001]. Intramuscular coherence obtained during challenging walking in individuals with iSCI may provide information on corticospinal gait control. The relationships between biomechanics, clinical scores, and neurophysiology suggest that intramuscular coherence assessed during challenging tasks may be meaningful for understanding impaired supra-spinal control in individuals with iSCI.
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Affiliation(s)
- Freschta Zipser-Mohammadzada
- Spinal Cord Injury Center, Department of Neurophysiology, Balgrist University Hospital, Zurich, Switzerland
- *Correspondence: Freschta Zipser-Mohammadzada,
| | - Bernard A. Conway
- Department of Biomedical Engineering, University of Strathclyde, Glasgow, United Kingdom
| | - David M. Halliday
- Department of Electronic Engineering, University of York, York, United Kingdom
- York Biomedical Research Institute, University of York, York, United Kingdom
| | - Carl Moritz Zipser
- Spinal Cord Injury Center, Department of Neurophysiology, Balgrist University Hospital, Zurich, Switzerland
| | - Chris A. Easthope
- Spinal Cord Injury Center, Department of Neurophysiology, Balgrist University Hospital, Zurich, Switzerland
- Cereneo Foundation, Center for Interdisciplinary Research, Vitznau, Switzerland
| | - Armin Curt
- Spinal Cord Injury Center, Department of Neurophysiology, Balgrist University Hospital, Zurich, Switzerland
| | - Martin Schubert
- Spinal Cord Injury Center, Department of Neurophysiology, Balgrist University Hospital, Zurich, Switzerland
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