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.

Study Overview

• Status: Recruiting
• Conditions: Healthy
• Intervention / Treatment: Device: Intermittent theta burst stimulation (iTBS)

Detailed Description

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.

• Study Type: Interventional
• Enrollment (Estimated): 40
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Georg Kranz, PhD; Phone Number: 4838 2766; Email: georg.kranz@polyu.edu.hk
• Study Contact Backup: Name: Weili Xia, MSc; Phone Number: 92859726; Email: weili-adam.xia@connect.polyu.hk

Study Locations

• Hong Kong
  • Hong Kong, Hong Kong
    • Recruiting
    • The Hong Kong Polytechnic University
    • Contact: Georg Kranz, PhD; Phone Number: 4838 2766; Email: georg.kranz@polyu.edu.hk

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Cortical hemodynamic variability of iTBS and its courses; A group of healthy adults shall undergo repeated experimental visits with concurrent TBS/fNIRS (3≤repetition≤15). An interval of at least two days (48 hours) between the visits is required to minimize carry-over effects from the iTBS protocols. Inter- (age, gender, personality inventory, etc.) and intra-individual factors (daily mood, daily sleep quality, physical activity levels, etc.) that are potentially moderating iTBS-induced excitability changes will be explored.

Device: Intermittent theta burst stimulation (iTBS); 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)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Oxygenated hemoglobin (HbO) change compared to baseline	iTBS-induced HbO change in the DLPFC before, during and after stimulation	During and post TBS-fNIRS measurement, up to 3 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Oxygen saturation change compared to baseline	iTBS-induced oxygen saturation change in the DLPFC before, during and after stimulation	During and post TBS-fNIRS measurement, up to 3 months
Deoxygenated hemoglobin (HbR) change compared to baseline	iTBS-induced HbR change in the DLPFC before, during and after stimulation	During and post TBS-fNIRS measurement, up to 3 months

Collaborators and Investigators

• Sponsor: The Hong Kong Polytechnic University
• Investigators: Principal Investigator: Georg Kranz, PhD, The Hong Kong Polytechnic University

Study record dates

Study Major Dates

• Study Start (Actual): October 18, 2023
• Primary Completion (Estimated): April 1, 2024
• Study Completion (Estimated): April 1, 2024

Study Registration Dates

• First Submitted: October 20, 2023
• First Submitted That Met QC Criteria: October 26, 2023
• First Posted (Actual): October 27, 2023

Study Record Updates

• Last Update Posted (Estimated): February 29, 2024
• Last Update Submitted That Met QC Criteria: February 28, 2024
• Last Verified: February 1, 2024

More Information

Terms related to this study

• Other Study ID Numbers: HSEARS20220812002-02

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: IPD may be shared upon request
• IPD Sharing Time Frame: Upon request
• IPD Sharing Access Criteria: Upon request
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No