Combined effects and timing of robotic training and botulinum toxin on upper limb spasticity and motor function: a single‑blinded randomized controlled pilot study.

Background: This study aimed to evaluate the combined effects of robotic training (RT) and botulinum toxin (BTX) injections on motor function and spasticity in individuals with post-stroke upper limb spasticity (ULS). We also sought to investigate the optimal timing of RT and BTX administration.

Methods: Forty-two participants with chronic stroke-induced ULS were initially enrolled and randomized into four groups: Group B4R4 (RT + BTX at 4 weeks [W4]), Group B0R0 (RT + BTX at baseline [W0]), Group B0R4 (BTX at W0, RT at W4), and Group B4R0 (RT at W0, BTX at W4). Clinical assessments and robotic kinematic evaluations were performed at W0, W4, and 8 weeks (W8). The primary outcome was the Fugl-Meyer assessment (FMA) score, and secondary outcomes included the modified Ashworth scale (MAS) of the elbow and kinematic parameters, such as spectral arc length, mean speed, hand path ratio, and movement deviation in various tasks. Changes in outcome measures over time were analyzed using a linear mixed-effects regression model or ordinal logistic regression.

Results: Of the 42 participants, 40 completed the study. From W0 to W4, Group B0R0 exhibited the most favorable outcomes in terms of spasticity (MAS-elbow flexor and extensor) and kinematic variables, suggesting that the combined application of BTX and RT is superior to sole interventions in improving motor function and spasticity. From W0 to W8, Group B0R4 demonstrated the most substantial improvements in FMA scores and kinematic parameters, indicating that the combined use of BTX and RT, particularly when RT is initiated 1 month after BTX injection, results in superior functional outcomes compared to other intervention timings.

Conclusions: The combination of RT and BTX is more effective in enhancing motor function and reducing spasticity in individuals with ULS than either intervention alone or no intervention. Furthermore, the timing of RT relative to BTX injection plays a critical role in maximizing therapeutic benefits in individuals with stroke and ULS, given the distinct modes of action of each intervention.

Trial registration: clinicaltrials.gov NCT02228863. The study was retrospectively registered on August 23, 2014.