Table 1 Template for Intervention Description and Replication (TIDieR)

1.

Brief name

Provide the name or a phrase that describes the intervention.

Infraslow closed-loop brain training for Anxiety & Depression (ISAD)

2.

Why

Describe any rationale, theory, or goal of the elements essential to the intervention.

Electrophysiological infraslow (<0.1 Hz) fluctuations (eISFs) are believed to coordinate and integrate information exchange within and between core-intrinsic connectivity networks (ICNs). Further, communication within and between core-ICNs has been found to be disrupted in internalizing disorder (ID) populations. We hypothesize that eISF neurofeedback (ISF-NFB) targeting key cortical nodes of these core-ICNs, may restore proper intra- and inter-network function and reduce ID-related symptoms.

3.

What

Materials: Describe any physical or informational materials used in the intervention, including those provided to participants or used in intervention delivery or training of intervention providers. Provide information on where the materials can be accessed (e.g. online appendix, URL).

19-channel sLORETA ISF-NFB training will be performed using a DC coupled amplifier (Brainmaster Technologies Inc.), ASUS laptop computer (ASUSTek Computer Inc.; 64.0 GB RAM; Intel Core i7 processor) running BrainAvatar software (version 4.7.5.844), 24 (Ag/AgCl) electrode Comby EEG caps, blunt needle, 5ml syringe, and electrolyte gel (Electro-Cap International Inc.). Free, open-source software (Audacity.com) is used to record/playback all auditory rewards during active/sham sessions.

4.

Procedures: Describe each of the procedures, activities, and/or processes used in the intervention, including any enabling or support activities.

Subjects will be asked to arrive with non-braided, clean, dry hair. They will be seated in a comfortable chair with their eyes closed in a quiet, cool (~15°C), dimly lit room. An appropriately sized Comby EEG cap will be affixed to the head and, using a blunt need and syringe, the scalp will be mildly abraded just prior to the application of the electrolyte gel beneath each electrode. EEGs will be recorded with the Ag/AgCl electrodes positioned according to the International 10–20 system (i.e. Fp1, Fp2, F3, F4, C3, C4, P3, P4, O1, O2, F7, F8, T3, T4, T5, T6, Fz, Cz, Pz) using a linked mastoids reference and a ground electrode positioned centrally between, F3, Fp1, Fz and Fpz. Impedances will be kept below 10 kΩ.

Immediately prior to each training period, a demonstration of motion/EMG artefact alerts will be provided with instructions to avoid eye/head/face movements to minimize this non-rewarding feedback. Participants will then be instructed to close their eyes, relax, stay awake, and listen to the sound being played. They will be informed that the sound they hear reflects that they are doing well.

Continuous, real-time auditory feedback (organ tones) will be used for reinforcement when the subject’s ISFs surpass the threshold(s). The reward threshold will be manually adjusted in real-time to maintain a 60% ± 10% success rate. The yoked-sham sessions will be identical to active sessions, including live EEG recordings and real-time motion/EMG artefact alerts, however the auditory rewards will derive from playbacks of consecutive, pre-recorded sessions of another female with IDs.

The trainer will remain present for the duration of all sessions to monitor the EEG.

5.

Who provided

For each category of intervention provider (e.g. psychologist, nursing assistant), describe their expertise, background and any specific training given.

A non-blinded doctoral student with 2+ years of training and experience in the administration of NFB

6.

How

Describe the modes of delivery (e.g. face-to-face or by some other mechanism, such as internet or telephone) of the intervention and whether it was provided individually or in a group.

sLORETA ISF-NFB sessions will be performed one-on-one and face-to-face

7.

Where

Describe the type(s) of location(s) where the intervention occurred, including any necessary infrastructure or relevant features.

sLORETA ISF-NFB sessions will take place in the EEG lab of the Department of Psychological Medicine, University of Otago, Dunedin, New Zealand.

8.

When and how much

Describe the number of times the intervention was delivered and over what period of time including the number of sessions, their schedule, and their duration, intensity or dose.

Participants will attend three 30-min sessions per week over 4 consecutive weeks (12 sessions in total).

9.

Tailoring

If the intervention was planned to be personalized, titrated or adapted, then describe what, why, when, and how.

Auditory feedback during active sLORETA ISF-NFB sessions will be based on each person’s real-time EEG-derived cortical ISFs. Thresholds will be manually adjusted, as needed, to maintain the pre-specified feedback success rate (i.e. 60% ± 10%)

10.

Modifications

If the intervention was modified during the study, describe the changes (what, why, when, and how).

Not applicable. This is a protocol.

11.

How well

Planned: If intervention adherence or fidelity was assessed, describe how and by whom, and if any strategies were used to maintain or improve fidelity, describe them.

Protocol adherence will be monitored by the trainer. Attempts will be made to mitigate adherence issues via automated email and text message reminders sent on the day of each training session.

12.

Actual: If intervention adherence or fidelity was assessed, describe the extent to which the intervention was delivered as planned.

Not applicable. This is a protocol.