A Neural Signature of Cortical Excitability Measurements to Predict Upper-Limb Motor Recovery in Post-Stroke Patients

Objective: This study examines whether clinical assessments and cortical excitability measurements are associated with upper-limb motor recovery in patients with subacute and chronic stroke. Methods: We conducted a secondary analysis of a double-blind, randomized trial (n=27) with 3 groups: 1 Hz rTMS with fluoxetine, sham rTMS with fluoxetine, and placebo fluoxetine with sham rTMS. Univariate and multivariate regression analyses assessed treatment response using FMA-UE and JTHF scores at 30 and 90 days, evaluating clinical variables and motor cortex excitability as predictors. Results: At 30 days, FMA-UE improvement was predicted by higher intracortical inhibition in the undamaged hemisphere ( P =0.03), motor-evoked potentials in the damaged hemisphere ( P =0.02), more exercise ( P =0.01), and early rehabilitation ( P =0.037). JTHF improvement was linked to lower intracortical facilitation ( P =0.002). At 90 days, less severe stroke ( P =0.037) and early rehabilitation ( P =0.007) predicted better outcomes. rTMS was not a key factor. Conclusions: The presence of motor-evoked potentials in the damaged hemisphere and higher intracortical inhibition in the undamaged hemisphere are linked to motor recovery. Intracortical excitability measures may serve as biomarkers for upper-limb recovery, especially during early-phase rehabilitation, supporting the interhemispheric competition hypothesis.