The Modulatory Effect of Low-intensity Priming Intermittent Theta Burst Stimulation on Motor Cortex Poststroke: a Concurrent TMS-EEG Study

The Modulatory Effect of Low-intensity Priming Intermittent Theta Burst Stimulation on Motor Cortex Poststroke: a Concurrent TMS-EEG Study

Background: The optimization of the intensity of priming theta burst stimulation increases the probability of success in a randomized controlled trial. We hypothesize that priming intermittent theta burst stimulation (iTBS) with a low-intensity continuous theta burst stimulation (cTBS) will yield superior effects than our original priming protocol in healthy adults and patients after stroke.

Methods: 20 stroke patients will undergo three separate experimental conditions: a low-intensity priming stimulation (55% resting motor threshold [RMT] cTBS+70% RMT iTBS), a conventional-intensity priming stimulation (70% RMT cTBS+70% RMT iTBS), and a nonpriming control. The alterations in cortical excitation/inhibition and its impacts on motor behaviors will be evaluated following stimulation.

Significance: The findings will inform future clinical trials investigating the optimized priming iTBS in promoting poststroke recovery.

Background: The optimization of the intensity of priming theta burst stimulation increases the probability of success in a randomized controlled trial. We hypothesize that priming intermittent theta burst stimulation (iTBS) with a low-intensity continuous theta burst stimulation (cTBS) will yield superior effects than our original priming protocol in healthy adults and patients after stroke.

Methods: 20 stroke patients will undergo three separate experimental conditions: a low-intensity priming stimulation (55% resting motor threshold [RMT] cTBS+70% RMT iTBS), a conventional-intensity priming stimulation (70% RMT cTBS+70% RMT iTBS), and a nonpriming control. The alterations in cortical excitation/inhibition and its impacts on motor behaviors will be evaluated following stimulation.

Significance: The findings will inform future clinical trials investigating the optimized priming iTBS in promoting poststroke recovery.

Inclusion Criteria:

• (1) have a diagnosis of ischemic or hemorrhagic stroke, with time after stroke onset≥6 months;
• (2) aged between 18 and 80 years old;
• (3) with residual upper limb functions from 2-7 levels in the Functional Test for the Hemiplegic Upper Extremity, i.e., moderately impaired overall upper extremity functions.
• (4) able to give informed written consent to participate in the study.

Exclusion Criteria:

• (1) any contraindications to TMS (screened by the safety checklist by Rossi [12]); -
• (2) any concomitant neurological disease;
• (3) any sign of moderate-to-severe cognitive problems, i.e., Montreal cognitive assessment (MoCA)<19/30
• (4) Modified Ashworth score>2 in hand, wrist or elbow extensor muscle in the hemiparetic upper extremity.

In addition, a group of age-matched, right-hand dominant healthy adults without any known neurological diseases will be enrolled. Healthy adults with any contraindications to TMS will be excluded.