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Completed

NCT Number: NCT06104462

Exploring the Cortical Hemodynamic Variability of Prefrontal iTBS: a Concurrent TBS/fNIRS Study

An increasing number of studies have used the intermittent theta-burst stimulation (iTBS) protocol to investigate neural plasticity non-invasively in the prefontal cortex in healthy humans and in patients with psychiatric disorders. However, the variability in the neurophysiological response to iTBS stimulation is high. The cause of this variability is multifactorial and to some degree still unknown. Therefore, the current study explores inter- and intra-individual factors that are potentially moderating iTBS-induced excitability changes. A greater understanding of these determinants would be highly valuable for optimizing the therapeutic application of iTBS.

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Key information

Conditions

Healthy

Age range

18 year–60 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

The Hong Kong Polytechnic University

Hong Kong

About this study

The investigators will measure the cortical excitability induced by iTBS with concurrent TBS/fNIRS technique in the same healthy individuals on multiple testing days. Meanwhile, several potential inter- (age, gender, etc.) and intra-individual factors (daily mood, daily physical activity levels, etc.) recently identified in non-invasive transcranial brain stimulation studies will be assessed before applying iTBS to the same individual on each testing day.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • healthiness based on history and psychiatric assessment
  • being able to hear and understand the verbal instructions
  • completed at least 6 years of formal education

Exclusion criteria

  • a current or past diagnosis of psychiatric, neurological disorders, or severe internal illness
  • any conditions that will contraindicate to iTBS or fNIRS
  • psychiatric disorders in their first-degree relatives
  • pregnancy

Treatment and study plan

intermittent theta burst stimulation (iTBS)

Device

The iTBS protocol consists of 20 trains of stimulation. Each train comprises ten 3-pulse bursts, delivered at an intra-burst frequency of 50 Hz, with a 5 Hz overall frequency, followed by 8 seconds of rest. A total of 600 pulses (10*3*20) will be administered in this 3-minute iTBS protocol. Concurrent TBS/fNIRS stimulation will be applied over the left DLPFC at an intensity of 90% of the resting motor threshold (RMT), which is considered appropriate to ensure compliance and elicit robust DLPFC activation.

Considering that the fNIRS optode beneath the coil increases the distance between the TMS coil and the skull by 10 mm, we will use the equation AdjMT% = MT + 2.8 * (Dsitex - Dm1). Therefore, 2.8 * 10 = 28% will be added to the normal intensity. The stimulation site over the DLPFC will be determined by the MNI coordinate (x-38, y+44, z+26) reported in previous studies.

Other names: Repetitive transcranial magnetic stimulation (rTMS)

Primary outcomes

  1. Oxygenated hemoglobin (HbO) change compared to baseline

    Time frame: During and post TBS-fNIRS measurement, up to 3 months

    iTBS-induced HbO change in the DLPFC before, during and after stimulation

Secondary outcomes

  1. Deoxygenated hemoglobin (HbR) change compared to baseline

    Time frame: During and post TBS-fNIRS measurement, up to 3 months

    iTBS-induced HbR change in the DLPFC before, during and after stimulation

  2. Oxygen saturation change compared to baseline

    Time frame: During and post TBS-fNIRS measurement, up to 3 months

    iTBS-induced oxygen saturation change in the DLPFC before, during and after stimulation

Sponsors and collaborators

Lead sponsor

The Hong Kong Polytechnic University

Other

Registry information

Important dates

Study start
2023
Primary completion
2024
Study completion
2024
First posted
Oct 27, 2023
Registry last updated
Sep 17, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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