Impairment-oriented training and adaptive motor cortex reorganisation after stroke: a fTMS study

Area of Science:

• Neuroscience
• Rehabilitation Medicine
• Neurology

Background:

• Subacute ischemic stroke often causes severe arm paresis, impacting motor cortex excitability and corticospinal function.
• Reduced motor cortex excitability and conduction velocity are observed in the affected hemisphere post-stroke.
• Motor cortex topology, specifically the abductor pollicis brevis (APB) representation, is initially comparable between hemispheres.

Purpose of the Study:

• To investigate the relationship between motor cortex changes and arm motor recovery after stroke.
• To evaluate the effectiveness of different rehabilitation interventions on motor recovery and neurophysiological changes.
• To identify predictors of motor recovery using transcranial magnetic stimulation (TMS) parameters.

Main Methods:

• Studied 28 subacute anterior circulation ischemic stroke patients with severe arm paresis.
• Utilized transcranial magnetic stimulation (TMS) to assess motor cortex excitability, conduction velocity, and map topology (APB representation).
• Employed a randomized controlled design to compare intensified vs. non-intensified therapy and Arm BASIS training vs. Bobath approach.

Main Results:

• Significant arm motor recovery (Fugl-Meyer test) was observed after four weeks of rehabilitation.
• Improvements in motor cortex excitability and corticospinal conduction velocity occurred in the affected hemisphere.
• A medial shift in APB representation predicted motor recovery, and this shift was associated with Arm BASIS training.

Conclusions:

• Changes in motor cortex topology, specifically a medial shift, are likely crucial for motor recovery post-stroke.
• Impairment-oriented training, such as Arm BASIS, demonstrates superior outcomes in improving motor control.
• Rehabilitation interventions may induce beneficial changes in motor cortex organization and function.