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Trial registered on ANZCTR

Registration number

ACTRN12618000911291

Ethics application status

Approved

Date submitted

18/05/2018

Date registered

30/05/2018

Date last updated

17/08/2018

Type of registration

Prospectively registered

Titles & IDs

Public title

The effects of brain training using Infraslow Neurofeedback on the control of the heart and blood vessels in healthy men

Scientific title

Effects of Infraslow Neurofeedback on alterations in heart rate and blood pressure in healthy men - a double blind randomised exploratory study

Secondary ID [1]

nil

Universal Trial Number (UTN)

U1111-1211-0349

Trial acronym

INCAS

Linked study record

nil

Health condition

Health condition(s) or problem(s) studied:

Cardiovascular Disease

Mental Health

Condition category

Condition code

Cardiovascular

Normal development and function of the cardiovascular system

Cardiovascular

Other cardiovascular diseases

Intervention/exposure

Study type

Interventional

Description of intervention(s) / exposure

20 healthy men between the ages of 18-64 years will be recruited from the community using advertisement in newspapers and on notice boards.

Those who are interested will be asked to attend a screening session at the clinic and will be provided with the participant information sheet. During this visit, consent will be obtained. The researcher will screen potential participants for eligibility. If eligible, the participant will undergo an electroencephalogram (EEG), cardiovascular autonomic nervous system assessments (ANS) and fill out a battery of questionnaires.

Subsequently, they will be randomised and will undergo either treatment infraslow (T-ISF)(n=10) or placebo infraslow (P-ISF) (n=10) for 6 sessions, This will be administered with 3 sessions during the first week, 2 sessions in the second week and 1 session in the third week. During the first session, the neurofeedback training will be for 10 minutes and the subsequent 5 sessions will be 20 minutes each. The duration for the first clinic session will take 30 mins while the other 5 sessions will take 45 minutes each.

During each session, participants will be asked to sit in a chair in an upright position and relax for 5 minutes. After careful skin preparation, the appropriate Comby EEG cap will be placed on the participant's head with reference electrodes at the mastoids. The impedance of the active electrodes will be kept between 2 to 5 kilo-ohms. Before the training period, participants will be instructed to relax and listen to the sound being played. A distinct tone will be used for T-ISF reinforcement at the Posterior Cingulate Cortex (PCC). Reward threshold will be adjusted in real time at above 90%. In other words, for 90% of the time, a sound will be played (reward) when the participant's brain activity meets the infraslow magnitude (threshold). For P-ISF, the simulation protocol by Brainmaster Inc will be administered.

Both T-ISF and P-ISF infraslow sLORETA neurofeedback will be implemented with a 24 channel DC coupled amplifier produced by Brainmaster Inc at the research clinic. During the training period, participants will be sitting upright in the chair with the infraslow Comby EEG cap attached. Throughout the sessions, participants will be asked to keep their eyes closed, relax and listen to the sound being played by the device.

Infraslow training will be administered by a researcher who has undergone training by Brainmaster Inc.

The researcher administering infraslow training will record the number of sessions attended. Primary and secondary outcomes will be assessed after the first neurofeedback session, after six sessions and two weeks after the last neurofeedback session.
The researchers will compare baseline characteristics (wellbeing, psychological variables) of those who complete the study to those who did not. This will help inform the researchers on strategies to improve compliance if a larger clinical trial is to be conducted.

Intervention code [1]

Treatment: Devices

Comparator / control treatment

The P-ISF set-up and instructions given to participants for P-ISF will be the same to T-ISF. However the simulation protocol by Brainmaster Inc. delivers a distinct tone at random thereby not reinforcing changes in infraslow activity and therefore acting as the control group.

Control group

Placebo

Outcomes

Primary outcome [1]

Heart rate/R-R interval

Seated heart rate will be continuously measured for 7 minutes and their responses assessed during alterations in breathing pattern – paced at 15 breaths per minute for 7 minutes and deep breathing paced at 6 breaths per minute for 6 – 8 breaths, and during and following a Valsalva manoeuvre.

Heart rate/R-R interval are measured with a standard limb lead (lead II) electrocardiogram.

All primary outcome measures are collected simultaneously with an analogue-to-digital converter (Powerlab/3508/P).

Timepoint [1]

Before and immediately after 1 session of infraslow training, 6 sessions of infraslow training and 1 week after the last infraslow training session.

This primary outcome measure along with primary outcomes 2 and 3 will be used to inform changes in cardiovascular autonomic function caused by the Infraslow intervention.

Primary outcome [2]

Blood Pressure

Seated blood pressure will be continuously measured for 7 minutes and their responses assessed during alterations in breathing pattern – paced at 15 breaths per minute for 7 minutes and deep breathing paced at 6 breaths per minute for 6 – 8 breaths, and during and following a Valsalva manoeuvre.

Beat-to-beat blood pressure is measured at the finger with photoplethysmography using a Finometer Midi [regularly calibrated with automated sphygmomanometer; (Connex ProBP 3400 series Welch Allyn)].

All primary outcome measures are collected simultaneously with an analogue-to-digital converter (Powerlab/3508/P).

Timepoint [2]

Before and immediately after 1 session of infraslow training, 6 sessions of infraslow training and 1 week after the last infraslow training session.

This primary outcome measure along with primary outcomes 1 and 3 will be used to inform changes in cardiovascular autonomic function caused by the Infraslow intervention.

Primary outcome [3]

Heart rate variability.

Heart rate variability will be assessed from the ECG signal collected in Primary outcome 1 during 5 minutes of steady-state data taken from the baseline and paced breathing conditions.

Heart variability is calculated using the a commercially avaliable HRV module in Labchart 8 (ADInstruments,Dunedin, NZ) using standard frequency and time domain analysis.

Timepoint [3]

Before and immediately after 1 session of infraslow training, 6 sessions of infraslow training and 1 week after the last infraslow training session.

This primary outcome measure along with primary outcomes 1 and 2 will be used to inform changes in cardiovascular autonomic function caused by the Infraslow intervention.

Secondary outcome [1]

Exploratory resting state brain activity.

Resting state EEG will be sampled using the international standard 19 electrode 10-20 system. EEG will be recorded continuously at 500 Hz using a Mitsar-EEG 202 DC amplifier for six minutes. Reference electrodes which are linked are place on the ears. Each electrode impedances are kept below 5 kilo-ohm for reliable recordings. The raw data recordings will be resampled at 128 Hz, band-pass filtered from 0.001 Hz to 44 Hz, plotted, and carefully inspected for manual artefact rejection on EEGLAB. Next, average power spectral matrices will be computed for bands infraslow (0.01 – 0.1 Hz), delta (2 – 3.5 Hz), theta (4 – 7.5 Hz), alpha (8 – 12 Hz), beta (12.5 – 30 Hz) and gamma (30 – 44 Hz).

Timepoint [1]

Before and immediately after 1 session of infraslow training, 6 sessions of infraslow training and 1 week after the last infraslow training session.

Secondary outcome [2]

World-Health Organization five well-being index.
A 5-item continuous scale assessing aspects of wellbeing within the last 1 week.

Timepoint [2]