Optimizing Cortical Priming

Participants received high-frequency (5 Hz) repetitive Transcranial Magnetic Stimulation (rTMS) delivered over the contralesional dorsal premotor cortex (cPMd) using a figure-of-eight magnetic coil. In Aim 1, participants received a single session of 5 Hz cPMd rTMS only. In Aim 2, participants who were responsive to cPMd stimulation received 5 Hz cPMd rTMS immediately prior to bilateral arm training (BAT) for 3 sessions.

Participant received 5 Hz repetitive transcranial magnetic stimulation (rTMS) on the contralesional dorsal premotor cortex (cPMd) only (Aim 1) and 5 Hz repetitive transcranial magnetic stimulation (rTMS) on the contralesional dorsal premotor cortex (cPMd) combined with 3 essions of bilateral arm training (Aim 2)

Participants received high-frequency (5 Hz) repetitive Transcranial Magnetic Stimulation (rTMS) delivered over the ipsilesional primary motor cortex (iM1) using a figure-of-eight magnetic coil. In Aim 1, participants received a single session of iM1 rTMS only. In Aim 2, participants who were responsive to iM1 stimulation received iM1 rTMS immediately prior to bilateral arm training (BAT) for 3 sessions.

Participant received 5 Hz rTMS on the ipsilesional primary motor cortex (iM1) only (Aim 1) and 5 Hz rTMS on the ipsilesional primary motor cortex (iM1) combined with 3 essions of bilateral arm training (Aim 2)

Cortical excitability was quantified using single-pulse Transcranial Magnetic Stimulation (TMS) over the targeted motor cortex. Peak-to-peak amplitude of Motor Evoked Potentials (MEPs) recorded from the target upper limb muscle via surface electromyography (EMG) was measured in microvolts to evaluate stimulation- and training-induced neuroplastic changes.

Interlimb coordination was quantified by measuring interlimb muscle coherence (intermuscular coherence) between homologous upper limb muscles via surface electromyography (EMG) during bilateral arm movements. Coherence was calculated in the frequency domain, where higher values indicated greater synchronous neural drive and coordination between the two upper limbs.

Upper limb kinematic performance during arm reaching tasks was assessed using the 3D Kinesiological Instrument (KINARM). Specific kinematic parameters analyzed included: (1) movement speed, (2) movement acceleration, (3) interlimb coordination, and (4) arm trajectory smoothness.

Intracortical inhibition was quantified using paired-pulse Transcranial Magnetic Stimulation (TMS) over the motor cortex, recorded via surface electromyography (EMG) from the target upper limb muscle. A subthreshold conditioning stimulus followed by a suprathreshold test stimulus was applied. Intracortical inhibition was expressed as the ratio or percentage of the conditioned Motor Evoked Potential (MEP) amplitude relative to the unconditioned test MEP amplitude (% of test MEP), where lower percentages indicated greater intracortical inhibition.

Interhemispheric inhibition was quantified by the Ipsilateral Silent Period (iSP), elicited by delivering single-pulse Transcranial Magnetic Stimulation (TMS) to the motor cortex ipsilateral to the target upper limb during voluntary isometric muscle contraction. The iSP was recorded via surface electromyography (EMG) and quantified by duration in milliseconds (ms) and normalized area of EMG suppression (%).

The Fugl-Meyer Assessment of the Upper Extremity (FMA-UE) is a performance-based impairment index used to assess upper limb motor recovery in individuals with post-stroke hemiparesis. The upper extremity motor domain consists of 33 items assessing movement, coordination, and reflex action of the shoulder, elbow, forearm, wrist, and hand. Each item is scored on a 3-point ordinal scale (0 = cannot perform, 1 = performs partially, 2 = performs fully), yielding a total motor score ranging from 0 to 66, where higher scores indicate better upper extremity motor function (less motor impairment).