Effects of Mirror-Box Therapy on Neuroplasticity and Functional Outcome in Hemiparetic Upper Limb Post Stroke: A Crossover Randomised Controlled Feasibility Study

Objective: Mirror-Box therapy (MBT) has immerged as an innovative, economical, task specific rehabilitation technique. However, little is known regarding its underlying mechanism. The objective of this work was to monitor the neuroplastic and functional effect of standard therapy (ST) and MBT as an adjuvant to ST in upper limb acute stroke using resting-state fMRI (rs-fMRI). Methods: 29 patients were screened. 7 patients were randomised to either ST (n=3) or MBT combined with ST (n=4). After 3 weeks patients crossed over into the other study arm for a further 3 weeks. Functional connectivity (FC) using rs-fMRI was utilised as the primary outcome measure. Secondary outcome measures were the Action-Research-Arm-Test(ARAT), Fugl Meyer Test(FMT), Barthel Index(BI), Pinch and Grip strength. Outcome measures were collected at baseline, 3 and 6 weeks. Results: At 3 weeks there was increased FC in the motor, anterior salience and left executive control network in the MBG and significant improvement in ARAT, FMT (motor) and BI (80% CI). There was no change in FC in the ST group. Mirror-Box FC increased linearly with pinch strength. FC gained during MBT was not lost after ST. After crossover, at 6 weeks, no statistical differences were observed compared to 3 weeks. FC and motor function gained during MBT was not lost after ST when compared to baseline. Conclusion: This is the first study using rs-fMRI to understand the underlying mechanism of MBT in stroke rehabilitation. In our patients, neuroplasticity could be augmented using MBT. Our findings of better functional outcomes and increased FC in patients that received MBT raises the question if rehabilitation therapies delivered today need to be adapted.