Stroke recovery beyond initial severity: The complementary roles of brain structure and brain function in acute stroke

Stroke frequently results in long-term upper limb (UL) motor impairments, limiting independence and quality of life. Accurate prediction of recovery trajectories is essential for personalizing rehabilitation strategies. While structural brain metrics such as corticospinal tract (CST) integrity have been widely studied, they incompletely explain motor outcome variability. Functional brain activity, quantified by sensorimotor activity in the beta ({beta}) frequency range has emerged as a promising biomarker of motor system integrity and plasticity potential. This study assessed in 30 acute stroke survivors and 26 healthy controls how combining functional and structural metrics of brain function relates to initial motor severity and subsequent recovery, using clinical MRI/CT and electroencephalography during passive finger movement and rest. Structurally, grey and white matter damage were associated with initial severity. No associations with recovery were found for structural metrics alone. Functionally, {beta}-activity in response to passive movement, and resting state activity were related to recovery, independent of initial impairment. Multivariate regression revealed that combining initial severity, structural information (CST damage) and brain function (sensorimotor {beta} activity) provided the most accurate prediction of both global and UL-specific recovery (R{superscript 2} = 80.1% and 74.3%, respectively). These findings underscore the importance of integrating functional and structural neural markers for improved stroke outcome prediction.