Objectives: This project will (1) establish the test-retest reliability of a novel transcranial magnetic stimulation-electroencephalography (TMS-EEG) interhemispheric inhibition (IHI) measure and (2) validate it against the TMS-EMG-based IHI measure (the gold standard). It will also (3) compare effects of dual-coil cortico-cortical paired associative stimulation (ccPAS) protocols with different interstimulus intervals (ISI) on this TMS-EEG-based IHI marker in poststroke patients. Methods: Study 1: IHI will be conducted in 20 stroke patients and 20 healthy counterparts using TMS-EEG and TMS-EMG; furthermore, both measures will be repeated after one week for test-retest reliability. Study 2: A randomized-crossover trial where 20 stroke patients undergo a single-session ccPAS in three separate visits (ISI: 8ms: LTD-like, 12ms: LTP-like, 100ms: sham) to investigate the differential modulatory effects in IHI.
(1) have a diagnosis of ischemic or hemorrhagic stroke, with time after stroke onset≥6 months. For stroke patients, we will invite participants to receive a structural magnetic resonance imaging (MRI) at the University Research Facility in Behavioral and Systems Neuroscience to verify their actual lesion location; (2) aged between 18 and 80 years old; (3) with residual upper limb functions from 4-7 levels in the Functional Test for the Hemiplegic Upper Extremity (Hong Kong version); (4) have evocable MEP from both M1; (5) able to give informed written consent to participate in the study. (6) able to understand and communicate with Chinese.
None
Crossover
Dual coil transcranial magnetic stimulation
DeviceThe ccPAS will be applied using a MagPro X100/R30 stimulator and a MagPro R20/R30 extension connected to two vertically oriented figure-of-eight coils designed for bilateral hemispheric stimulation.
transcranial magnetic stimulation-evoked potential in electroencephalography (TMS-EEG)
The amplitude of P30 (28-35ms) will be extracted from the artifact-free TEP trials to represent the cortical excitatory activity.
Transcranial magnetic stimulation-evoked potential in electroencephalography
The amplitude of P30 (28-35ms) will be extracted from the artifact-free TEP trials to represent the cortical excitatory activity.
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