Bilateral corticospinal tract asymmetry predicts motor recovery after transcranial direct current stimulation in subacute stroke patients

Motivation: A reliable neuroimaging biomarker to predict motor improvement after neuromodulation is lacking. Goal(s): We compared the integrity of bilateral corticospinal tracts and evaluated the asymmetry before tDCS. The association between the motor improvement and pretreatment integrity of the CST was identified to predict motor recovery in subacute stroke patients. Approach: We calculated the asymmetry and fractional anisotropy between bilateral CST. The linear regression analysis was conducted to predict the motor recovery. Results: The patients with more severe motor impairment have higher asymmetry in CST. The tDCS regression models achieved an R2=0.796 and 0.624 for predicting FMA at three months after stroke onset. Impact: The ischemic stroke patients with higher degree of right white matter integrity have better response to neural modulation effects of tDCS treatment. The identified DTI predictors could be the basis for optimizing the treatment protocols of tDCS in stroke patient.