Early Motor Cortex Dysconnectivity and Compensatory Neuronal Reactivity in Intracerebral Hemorrhage: A Continuous-Wave Functional Near-Infrared Spectroscopy Study

Insights into motor cortex remodelling may allow for the implementation of better rehabilitation strategies in the acute phase. We aim to assess the affected and unaffected motor/premotor/somatosensory cortex resting state functional connectivity (RSFC) and reactivity with continuous wave functional near-infrared spectroscopy(cw-fNIRS) in patients with ICH compared to age, sex, and comorbidity-matched subjects. We enrolled patients with acute-subacute hemispheric ICH (n=35) and grouped them according to the side (Right and Left) of the stroke. Matched participants or patients with recent transient ischemic attack were enrolled as control subjects for the study (n=39). RSFC was assessed in both affected and unaffected hemispheres by group-level seed-based (Primary Motor cortex, priMC) correlation analysis. FT-associated relative Oxyhemoglobin (ΔHbO) changes were analyzed in affected and unaffected hemispheres with generalized linear model regression. In left hemispheric ICH, the resting state coherence between the af-fected priMC and the affected premotor cortex (preMC) is increased (β = 0.83, 95% CI = 0.19, 1.47, p = 0.01), whereas in right hemispheric ICH, the coherence between the unaffected priMC and the affected PreMC is decreased (β = -0.6, 95% CI = -1.12, -0.09, p = .02). In left hemispheric ICH, the left-hand FT was associated with increased ΔHbO over the affected preMC (β = 0.01, 95% CI = 0.003, 0.02, p = .01) whereas in right hemispheric ICH, the left-hand FT was associated with increased ΔHbO over the unaffected preMC (β = 0.02, 95% CI = 0.006, 0.04, p = .01). Left hemispheric preMC is involved in motor cortex re-organization in acute ICH in either hemisphere. Further studies may be required to assess longitudinal changes in motor cortex reorganization to inform acute motor rehabilitation.