Prefrontal iTBS on Working Memory

Study Overview
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Brief Summary
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The investigators previous pilot study showed that the brain remained activated after 3 minutes of intermittent theta burst stimulation (iTBS). Therefore, an open question remains that how long the effects will last and when the maximum effects will be achieved. In addition, many pioneering works showed the positive effects of repetitive transcranial magnetic stimulation (rTMS) on working memory. Intermittent theta burst stimulation (iTBS) is a patterned form of rTMS, it has shown a non-inferior efficacy in depression but with a much shorter time (approximately 3 mins) than traditional rTMS (approximately 40 mins). As discussed above, this study aims to investigate the effects of prefrontal iTBS on working memory using concurrent iTBS/fNIRS and to explore the duration of the effects.

Official Title
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Exploring the Effects of Prefrontal iTBS on Working Memory in Healthy Participants: a Concurrent TMS/fNIRS Study

Conditions
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Healthy

Intervention / Treatment
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* Device: Transcranial magnetic stimulation (TMS)-active
* Device: Transcranial magnetic stimulation (TMS)-sham


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: right-handed participants normal or corrected-to-normal vision Exclusion Criteria: a current or past diagnosis of any neurological or psychiatric disorder any severe medical conditions, seizure, and pregnancy contraindication to TMS (e.g., with mental implants)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 35 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: Healthy volunteers will receive iTBS two times with active or sham stimulation separated by one week to investigate the effect duration of iTBS on working memory
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Active iTBS on working memory<br>Participants will receive active 80% rMT iTBS over the left DLPFC in this arm. The working memory assessments will be performed pre-stimulation and at 0-, 10-, 20-, 30-, and 40-min post-stimulation. The working memory assessment is measured using a 2-minute 3-back task. The fNIRS will monitor the prefrontal hemoglobin change throughout the whole procedure. | Device: Transcranial magnetic stimulation (TMS)-active<br>* Active intermittent TBS (iTBS) will be applied to the left DLPFC at 80% of the resting motor threshold (rMT) (Hoy et al., 2016). A stimulation, where 3-pulse at 50 Hz will be given, will repeat every 10 s for a total of 190 s (600 pulses in total) (Huang et al., 2005). The left DLPFC stimulation site will be determined using the neuronavigator system (lDLPFC, x-38, y+44, z+26).<br>|
| Sham Comparator: Sham iTBS on working memory<br>Participants will receive sham 80% rMT iTBS over the left DLPFC (by putting the coil perpendicular to the left DLPFC) in this arm. The working memory assessments will be performed pre-stimulation and at 0-, 10-, 20-, 30-, and 40-min post-stimulation. The working memory assessment is measured using a 2-minute 3-back task. The fNIRS will monitor the prefrontal hemoglobin change throughout the whole procedure. | Device: Transcranial magnetic stimulation (TMS)-sham<br>* Sham intermittent TBS (iTBS) will be applied to the left DLPFC at 80% of the resting motor threshold (rMT) (Hoy et al., 2016). The coil will be placed perpendicular to the left DLPFC. A stimulation, where 3-pulse at 50 Hz will be given, will repeat every 10 s for a total of 190 s (600 pulses in total) (Huang et al., 2005). The left DLPFC stimulation site will be determined using the neuronavigator system (lDLPFC, x-38, y+44, z+26).<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| N-back | The accuracy number of each n-back task | before and post iTBS, up to 3 months | 
| N-back | The response time of each n-back task | before and post iTBS, up to 3 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Hemoglobin change | The hemoglobin change throughout whole procedure. | before and post iTBS, up to 3 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Theta-Burst stimulation (iTBS), Functional near-infrared spectroscopy (fNIRS), Concurrent TMS/fNIRS, Working memory