Anatomy and physiology predict response to motor cortex stimulation after stroke

Area of Science:

• Neuroscience
• Rehabilitation Medicine
• Clinical Trials

Background:

• Epidural motor cortex stimulation showed promise in preclinical stroke models.
• Human phase III trials failed to confirm these benefits, necessitating further investigation.

Purpose of the Study:

• To identify patient characteristics that predict response to epidural motor cortex stimulation after stroke.
• To distinguish responders from non-responders in a randomized clinical trial.

Main Methods:

• Retrospective analysis of 60 subjects randomized to cortical stimulation.
• Assessment of anatomic factors (MRI: gray matter thickness, white matter tract injury).
• Evaluation of physiologic factors (motor evoked responses - MER).

Main Results:

• Baseline anatomic and physiologic measures predicted behavioral response.
• Less corticospinal tract injury (44% vs 72%) and preserved MER (67% vs 27%) correlated with better outcomes.
• Preserved MER was associated with less precentral gyrus injury and higher gray matter volume.

Conclusions:

• Physiologic integrity of the motor system is crucial for deriving gains from restorative stroke therapy.
• Functional and structural preservation of brain substrates are key predictors of treatment success.