Sensorimotor modulation by botulinum toxin A in post-stroke arm spasticity: Passive hand movement

Area of Science:

• Neuroscience
• Rehabilitation Medicine
• Medical Imaging

Background:

• Post-stroke spasticity affects sensorimotor networks.
• Botulinum toxin type A (BoNT) is a potential therapy.
• Functional imaging can reveal treatment-related brain modulation.

Purpose of the Study:

• To localize brain activation changes in stroke patients treated with BoNT for upper limb spasticity.
• To investigate the effects of BoNT on central sensorimotor networks using fMRI.
• To correlate fMRI findings with spasticity scores.

Main Methods:

• Seven stroke patients with upper limb spasticity underwent fMRI scans.
• Scans were performed before (W0), 4 weeks (W4), and 11 weeks (W11) post-BoNT treatment.
• fMRI data were acquired during passive hand movements, analyzed using GLM in FSL.

Main Results:

• BoNT transiently reduced spasticity (MAS scores) at W4.
• fMRI showed increased activation in the cerebellum and contralesional sensorimotor/occipital cortex at W4 compared to W0.
• Decreased activation was observed in the ipsilesional sensorimotor cortex from W0 to W11.

Conclusions:

• Passive hand movements can map sensorimotor networks in post-stroke spasticity.
• BoNT therapy for spasticity is associated with changes in task-induced brain activation.
• Altered afferent drive from spastic muscles likely mediates these neuroplastic changes.