Exploratory study of how cognitive multisensory rehabilitation restores parietal operculum connectivity and improves upper limb movements in chronic stroke 

Abstract Cognitive multisensory rehabilitation (CMR) is a promising therapy for upper limb recovery in stroke, but the brain mechanisms are unknown. We previously demonstrated that the parietal operculum (parts OP1/OP4) is activated with CMR exercises. In this exploratory study, we assessed the baseline difference between OP1/OP4 functional connectivity (FC) in the brain at rest in stroke versus healthy adults to then explore whether CMR affects OP1/OP4 connectivity and motor recovery after stroke.We recruited 8 adults with chronic stroke and left hemiplegia/paresis and 22 healthy adults. Resting-state FC with the OP1/OP4 region-of-interest in the affected hemisphere was analysed before and after 6 weeks of CMR. We evaluated sensorimotor function and activities of daily life pre- and post-CMR, and at 1-year post-CMR.We found decreased FC between the right OP1/OP4 and 34 areas distributed across all lobes in stroke versus healthy adults. After CMR, only four areas had decreased FC compared to healthy adults. Participants improved on motor function (MESUPES, p=0.03; Fugl-Meyer, p=0.006), with those improvements maintained at 1-year follow-up. Stereognosis and Frenchay test (both p=0.03) improved from pre-CMR to 1-year follow-up, suggesting enhancing sensorimotor recovery post-stroke by CMR. Our results from this exploratory study justify larger-scale studies.