Table 3.
Longitudinal changes in effective connectivity during affected hand movements in stroke patients for coupling parameters showing significant alterations compared to healthy subjects (see Table 2).
| Connection modulated by affected hand movements | Mean (SD) coupling strength controlsa | Mean Δ in coupling (SEM) across time | Correlation with composite motor recovery scoreb |
|---|---|---|---|
| Changes from session 1 to session 3 (n=10) | |||
| IL SMA–IL M1 | +0.1717 (0.0346) | Δ +0.064 (0.024) | r=0.75 (p=0.007) |
| IL M1–CL M1 | −0.0592 (0.0332) | Δ−0.030d (0.009) | n.s. |
| Changes from session 2 to session 3 (n=10) | |||
| IL SMA–CL M1 | −0.0783 (0.0565) | Δ−0.028d (0.008) | n.s. |
| IL M1–CL M1 | −0.0600 (0.0426) | Δ−0.015d (0.006) | n.s. |
| IL PMC–CL M1 | −0.0600 (0.0426) | Δ−0.018d (0.006) | n.s. |
| CL M1–IL M1 | −0.0142 (0.0326) n.s.c | Δ−0.019d (0.005) | n.s. |
| Changes from session 1 to session 2 (n=10) | |||
| CL PMC–IL M1 | +0.1075 (0.0443) | Δ +0.055 (0.017) | n.s. |
| Changes from session 1 to session 2 (n=12) | |||
| IL SMA–IL M1 | +0.1717 (0.0346) | Δ +0.051 (0.021) | n.s. |
| CL PMC–IL M1 | +0.1075 (0.0443) | Δ +0.051 (0.015) | n.s. |
CL, contralesional; IL, ipsilesional; M1, primary motor cortex; n.s., not significant, i.e., p>0.05 corrected; PMC, ventral premotor cortex; SEM, standard error of the mean; SMA, supplementary motor area.
Coupling parameters in healthy subjects are given as a reference frame: positive coupling parameters describe promoting influences, negative coupling parameters describe inhibitory influences.
Composite motor recovery scores represent the factor values of the first principal component resulting from a PCA of ARAT and grip force improvement scores for the respective time interval.
Coupling parameter was not different from zero in a one-sample t-test within the respective group (p<0.05 FDR-corrected).
Negative changes in inhibitory influences indicate an increase in inhibition (i.e., “re-inhibition”).