TY - JOUR
T1 - CMC is more than a measure of corticospinal tract integrity in acute stroke patients
AU - Aikio, R.
AU - Laaksonen, K.
AU - Sairanen, V.
AU - Parkkonen, E.
AU - Abou Elseoud, A.
AU - Kujala, J.
AU - Forss, N.
N1 - Funding Information:
This work was financially supported by Helsinki University Hospital Research Fund and TEKES, the Finnish Funding Agency for Technology and Innovation .
Publisher Copyright:
© 2021 The Authors
PY - 2021/1
Y1 - 2021/1
N2 - In healthy subjects, motor cortex activity and electromyographic (EMG) signals from contracting contralateral muscle show coherence in the beta (15–30 Hz) range. Corticomuscular coherence (CMC) is considered a sign of functional coupling between muscle and brain. Based on prior studies, CMC is altered in stroke, but functional significance of this finding has remained unclear. Here, we examined CMC in acute stroke patients and correlated the results with clinical outcome measures and corticospinal tract (CST) integrity estimated with diffusion tensor imaging (DTI). During isometric contraction of the extensor carpi radialis muscle, EMG and magnetoencephalographic oscillatory signals were recorded from 29 patients with paresis of the upper extremity due to ischemic stroke and 22 control subjects. CMC amplitudes and peak frequencies at 13–30 Hz were compared between the two groups. In the patients, the peak frequency in both the affected and the unaffected hemisphere was significantly (p < 0.01) lower and the strength of CMC was significantly (p < 0.05) weaker in the affected hemisphere compared to the control subjects. The strength of CMC in the patients correlated with the level of tactile sensitivity and clinical test results of hand function. In contrast, no correlation between measures of CST integrity and CMC was found. The results confirm the earlier findings that CMC is altered in acute stroke and demonstrate that CMC is bidirectional and not solely a measure of integrity of the efferent corticospinal tract.
AB - In healthy subjects, motor cortex activity and electromyographic (EMG) signals from contracting contralateral muscle show coherence in the beta (15–30 Hz) range. Corticomuscular coherence (CMC) is considered a sign of functional coupling between muscle and brain. Based on prior studies, CMC is altered in stroke, but functional significance of this finding has remained unclear. Here, we examined CMC in acute stroke patients and correlated the results with clinical outcome measures and corticospinal tract (CST) integrity estimated with diffusion tensor imaging (DTI). During isometric contraction of the extensor carpi radialis muscle, EMG and magnetoencephalographic oscillatory signals were recorded from 29 patients with paresis of the upper extremity due to ischemic stroke and 22 control subjects. CMC amplitudes and peak frequencies at 13–30 Hz were compared between the two groups. In the patients, the peak frequency in both the affected and the unaffected hemisphere was significantly (p < 0.01) lower and the strength of CMC was significantly (p < 0.05) weaker in the affected hemisphere compared to the control subjects. The strength of CMC in the patients correlated with the level of tactile sensitivity and clinical test results of hand function. In contrast, no correlation between measures of CST integrity and CMC was found. The results confirm the earlier findings that CMC is altered in acute stroke and demonstrate that CMC is bidirectional and not solely a measure of integrity of the efferent corticospinal tract.
KW - Afferent input
KW - Corticomuscular coherence
KW - Corticospinal tract integrity
KW - Magnetoencephalography
KW - Motor cortex
KW - Stroke
UR - http://www.scopus.com/inward/record.url?scp=85115151450&partnerID=8YFLogxK
U2 - 10.1016/j.nicl.2021.102818
DO - 10.1016/j.nicl.2021.102818
M3 - Article
AN - SCOPUS:85115151450
SN - 2213-1582
VL - 32
JO - NeuroImage: Clinical
JF - NeuroImage: Clinical
M1 - 102818
ER -