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Trial registered on ANZCTR


Registration number
ACTRN12624000313538p
Ethics application status
Submitted, not yet approved
Date submitted
31/01/2024
Date registered
22/03/2024
Date last updated
30/07/2024
Date data sharing statement initially provided
22/03/2024
Type of registration
Prospectively registered

Titles & IDs
Public title
Brain stimulation to target slow brain waves and cognition in obstructive sleep apnea
Scientific title
Slow oscillation transcranial direct current stimulation in adults with obstructive sleep apnea: a proof-of-concept study
Secondary ID [1] 311394 0
nil
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
obstructive sleep apnea 332667 0
Condition category
Condition code
Respiratory 329372 329372 0 0
Sleep apnoea

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Proof of concept/ Feasibility study.
We aim to assess if it is feasible to apply slow oscillation-transcranial direct current stimulation to two regions, frontal and parietal, to enhance slow wave activity in middle to late age people with obstructive sleep apnea. We will recruit 5 participants for this proof of concept, feasibility study. Participants will complete 3 daytime nap studies at the Woolcock Institute, with at least 1 week washout between sessions. At the visits they will complete a memory and a cognition task before and after a 90-minute nap with each condition of slow-oscillation transcranial direct current stimulation (so-tDCS) applied at each visit (2 active stimulation montages and sham). Participants will be fitted with a high-density electroencephalography (EEG) net with the stimulation electrodes nested between the cap. Stimulation will be applied using the Soterix M×N 33/65 High Definition-transcranial Electrical Stimulator using sintered HD electrodes. Active stimulation will consist of an anodal current sinusoidally oscillating at a frequency of 0.75 Hz between zero and 260 µA. The maximum current density will be 0.522 mA/cm2. Channel impedance will be <2 kO. The low level so-tDCS stimulation will be applied in 5 x 5-minute stimulation blocks by trained researchers. Following each nap participants will complete a perceived effects and tolerability questionnaire.
Intervention code [1] 327832 0
Treatment: Devices
Comparator / control treatment
The sham condition will be identical to the stimulation conditions however the stimulation intensity will not be high enough to generate meaningful cortical excitability (>0.1mA).
Control group
Placebo

Outcomes
Primary outcome [1] 338974 0
Technical Feasibility
Assessment method [1] 338974 0
Technical feasibility will be measured by the percentage of randomised participants successfully reaching stable NREM sleep, completing the stimulation blocks and EEG recording in the post stimulation block. Success will be defined by 80% of randomised participants reaching stable NREM (N2 and N3) sleep and all five stimulation blocks being completed, and EEG measured post stimulation in at least one active and one sham condition.
Timepoint [1] 338974 0
Primary outcome [2] 338975 0
Technical Feasibility
Assessment method [2] 338975 0
Technical feasibility will be measured by the percentage of randomised participants successfully reaching stable NREM sleep, completing the stimulation blocks and EEG recording in the post stimulation block. Success will be defined by 80% of randomised participants reaching stable NREM (N2 and N3) sleep and all five stimulation blocks being completed, and EEG measured post stimulation in at least one active and one sham condition.
Timepoint [2] 338975 0
Technical feasibility will be measured at each visit and calculated at the end of the study.
Secondary outcome [1] 438138 0
Acceptability
Assessment method [1] 438138 0
Acceptability will be measured by calculating the percentage of participants that are eligible out of participants screened, the percentage of participants who complete the protocol out of participants who are eligible, and the time taken to complete recruitment in months. This outcome is for descriptive purposes, there is no hypothesis testing. Recruitment will be tracked using spreadsheets.
Timepoint [1] 438138 0
Secondary outcome [2] 438139 0
Acceptability
Assessment method [2] 438139 0
Acceptability will be measured by calculating the percentage of participants that are eligible out of participants screened, the percentage of participants who complete the protocol out of participants who are eligible, and the time taken to complete recruitment in months. This outcome is for descriptive purposes, there is no hypothesis testing. Recruitment will be tracked using spreadsheets.
Timepoint [2] 438139 0
Acceptability will be measured at the end of the study.
Secondary outcome [3] 438140 0
Blinding & perceived effects
Assessment method [3] 438140 0
Blinding & perceived effects will be measured by the subjective perceived effects and tolerability questionnaire. Blinding will be measured by the number of people who correctly guess the treatment allocation (active or sham). Perceived effects will be measured by Likert scale questions on stimulation tolerability, effects on sleep interference and quality and participation burden. This outcome is for descriptive purposes, there is no hypothesis testing.
Timepoint [3] 438140 0
Acceptability will be measured at the end of the study.
Secondary outcome [4] 438141 0
Blinding & perceived effects
Assessment method [4] 438141 0
Blinding & perceived effects will be measured by the subjective perceived effects and tolerability questionnaire. Blinding will be measured by the number of people who correctly guess the treatment allocation (active or sham). Perceived effects will be measured by Likert scale questions on stimulation tolerability, effects on sleep interference and quality and participation burden. This outcome is for descriptive purposes, there is no hypothesis testing.
Timepoint [4] 438141 0
Blinding & perceived effects will be measured at the end of each visit and at the end of the study.
Secondary outcome [5] 438142 0
Delta power
Assessment method [5] 438142 0
Delta power will be measured using a high-density electroencephalography (EEG) net. EEG will be recorded 40 seconds after each stimulation block for 60 seconds (frequency bands; 0.5-1Hz and 1-4.5Hz) and averaged across measurement blocks. Fast Fourier transformation methods will be used to extract EEG spectral densities (µV2). Data will be calculated regionally at each electrode and globally as an average of all channels.
Timepoint [5] 438142 0
Blinding & perceived effects will be measured at the end of each visit and at the end of the study.
Secondary outcome [6] 438143 0
Delta power
Assessment method [6] 438143 0
Delta power will be measured using a high-density electroencephalography (EEG) net. EEG will be recorded 40 seconds after each stimulation block for 60 seconds (frequency bands; 0.5-1Hz and 1-4.5Hz) and averaged across measurement blocks. Fast Fourier transformation methods will be used to extract EEG spectral densities (µV2). Data will be calculated regionally at each electrode and globally as an average of all channels.
Timepoint [6] 438143 0
The primary outcome will be assessed at all study visits. Electroencephalography will be measured after each stimulation block.
Secondary outcome [7] 438144 0
Visuo-spatial recognition accuracy (tertiary outcome).
Assessment method [7] 438144 0
Visuo-spatial recognition accuracy will be measured with the image based visuo-spatial task. Visual and spatial recognition accuracy percentage will be calculated using signal detection theory calculations. The change in recognition accuracy between pre- and post-nap recognition trials will be calculated.
Timepoint [7] 438144 0
The primary outcome will be assessed at all study visits. Electroencephalography will be measured after each stimulation block.
Secondary outcome [8] 438145 0
Visuo-spatial recognition accuracy (tertiary outcome).
Assessment method [8] 438145 0
Visuo-spatial recognition accuracy will be measured with the image based visuo-spatial task. Visual and spatial recognition accuracy percentage will be calculated using signal detection theory calculations. The change in recognition accuracy between pre- and post-nap recognition trials will be calculated.
Timepoint [8] 438145 0
The visuo-spatial task will be measured 30 minutes before and after the nap at each of the visits.
Secondary outcome [9] 438146 0
Vigilance (tertiary outcome).
Assessment method [9] 438146 0
Vigilance will be assessed using the psychomotor vigilance task. The PVT response variables to be analysed are: a) mean reciprocal reaction time (RT); b) mean of the fastest 10% of RTs; c) mean reciprocal of slowest 10% of RTs; and, d) number of lapses (response time >500ms). The change in PVT variables between pre- and post-nap recognition trials will be calculated.
Timepoint [9] 438146 0
The visuo-spatial task will be measured 30 minutes before and after the nap at each of the visits.
Secondary outcome [10] 438147 0
Vigilance (tertiary outcome).
Assessment method [10] 438147 0
Vigilance will be assessed using the psychomotor vigilance task. The PVT response variables to be analysed are: a) mean reciprocal reaction time (RT); b) mean of the fastest 10% of RTs; c) mean reciprocal of slowest 10% of RTs; and, d) number of lapses (response time >500ms). The change in PVT variables between pre- and post-nap recognition trials will be calculated.
Timepoint [10] 438147 0
The psychomotor vigilance task will be measured 30 minutes before and after the nap at each of the visits.
Secondary outcome [11] 438148 0
Sigma power (tertiary outcome)
Assessment method [11] 438148 0
Sigma power will be measured using a high-density electroencephalography (EEG) net. EEG will be recorded 40 seconds after each stimulation block for 60 seconds (overall 11-16, slow: 11-13Hz, fast 13-16Hz) and averaged across measurement blocks. Fast Fourier transformation methods will be used to extract EEG spectral densities (µV2). Data will be calculated regionally at each electrode and globally as an average of all channels
Timepoint [11] 438148 0
The psychomotor vigilance task will be measured 30 minutes before and after the nap at each of the visits.
Secondary outcome [12] 438149 0
Sigma power (tertiary outcome)
Assessment method [12] 438149 0
Sigma power will be measured using a high-density electroencephalography (EEG) net. EEG will be recorded 40 seconds after each stimulation block for 60 seconds (overall 11-16, slow: 11-13Hz, fast 13-16Hz) and averaged across measurement blocks. Fast Fourier transformation methods will be used to extract EEG spectral densities (µV2). Data will be calculated regionally at each electrode and globally as an average of all channels
Timepoint [12] 438149 0
The outcome will be assessed at all study visits. Electroencephalography will be measured after each stimulation block.
Secondary outcome [13] 438150 0
Slow oscillation events (tertiary outcome).
Assessment method [13] 438150 0
Slow oscillation events will be measured using a high-density electroencephalography (EEG) net. EEG will be recorded 40 seconds after each stimulation block for 60 seconds. Events will be measured using automated detection algorithms. A priori event markers are slow oscillation count per minute (n/min), mean slow oscillation duration (s) and mean peak-to-peak amplitude (µV).
Timepoint [13] 438150 0
The outcome will be assessed at all study visits. Electroencephalography will be measured after each stimulation block.
Secondary outcome [14] 438151 0
Slow oscillation events (tertiary outcome).
Assessment method [14] 438151 0
Slow oscillation events will be measured using a high-density electroencephalography (EEG) net. EEG will be recorded 40 seconds after each stimulation block for 60 seconds. Events will be measured using automated detection algorithms. A priori event markers are slow oscillation count per minute (n/min), mean slow oscillation duration (s) and mean peak-to-peak amplitude (µV).
Timepoint [14] 438151 0
The outcome will be assessed at all study visits. Electroencephalography will be measured in NREM (N2 and N3) sleep after each stimulation block.
Secondary outcome [15] 438152 0
Sleep spindle events (tertiary outcome).
Assessment method [15] 438152 0
Sleep spindle events will be measured using a high-density electroencephalography (EEG) net. EEG will be recorded 40 seconds after each stimulation block for 60 seconds. will be measured using automated detection algorithms. A priori event markers are spindle count per minute (n/min), mean sleep spindle duration (s) and mean peak-to-peak amplitude (µV).
Timepoint [15] 438152 0
The outcome will be assessed at all study visits. Electroencephalography will be measured in NREM (N2 and N3) sleep after each stimulation block.
Secondary outcome [16] 438153 0
Sleep spindle events (tertiary outcome).
Assessment method [16] 438153 0
Sleep spindle events will be measured using a high-density electroencephalography (EEG) net. EEG will be recorded 40 seconds after each stimulation block for 60 seconds. will be measured using automated detection algorithms. A priori event markers are spindle count per minute (n/min), mean sleep spindle duration (s) and mean peak-to-peak amplitude (µV).
Timepoint [16] 438153 0
The outcome will be assessed at all study visits. Electroencephalography will be measured in NREM (N2 and N3) sleep after each stimulation block.
Secondary outcome [17] 438154 0
Slow oscillation and sleep spindle coupling events (tertiary outcome).
Assessment method [17] 438154 0
Slow oscillation and sleep spindle coupling events will be measured using a high-density electroencephalography (EEG) net. EEG will be recorded 40 seconds after each stimulation block for 60 seconds. will be measured using automated detection algorithms. A priori output metrics of interest are: (i) coupled spindle density (calculated as the count of spindles that are coupled to a slow oscillation per minute; n/min); (ii) ratio of coupled spindles to total slow oscillations; and (iii) ratio of coupled spindles to total spindles (%).
Timepoint [17] 438154 0
The outcome will be assessed at all study visits. Electroencephalography will be measured in NREM (N2 and N3) sleep after each stimulation block.
Secondary outcome [18] 438155 0
Slow oscillation and sleep spindle coupling events (tertiary outcome).
Assessment method [18] 438155 0
Slow oscillation and sleep spindle coupling events will be measured using a high-density electroencephalography (EEG) net. EEG will be recorded 40 seconds after each stimulation block for 60 seconds. will be measured using automated detection algorithms. A priori output metrics of interest are: (i) coupled spindle density (calculated as the count of spindles that are coupled to a slow oscillation per minute; n/min); (ii) ratio of coupled spindles to total slow oscillations; and (iii) ratio of coupled spindles to total spindles (%).
Timepoint [18] 438155 0
The outcome will be assessed at all study visits. Electroencephalography will be measured in NREM (N2 and N3) sleep after each stimulation block.
Secondary outcome [19] 438156 0
Sleep macro-architecture (tertiary outcome).
Assessment method [19] 438156 0
Electroencephalography will be measured during the nap. Events will be measured using manual scoring (AASM criteria). Measures include time in bed (min), total sleep time (min), sleep onset latency (min), rem onset latency (min), wake after sleep onset (%), rapid eye movement sleep (min and %), non-rapid eye movement sleep (min and %), sleep stages 1-3(min and %), arousal index (n/hr).

Timepoint [19] 438156 0
The outcome will be assessed at all study visits. Electroencephalography will be measured in NREM (N2 and N3) sleep after each stimulation block.
Secondary outcome [20] 438157 0
Sleep macro-architecture (tertiary outcome).
Assessment method [20] 438157 0
Electroencephalography will be measured during the nap. Events will be measured using manual scoring (AASM criteria). Measures include time in bed (min), total sleep time (min), sleep onset latency (min), rem onset latency (min), wake after sleep onset (%), rapid eye movement sleep (min and %), non-rapid eye movement sleep (min and %), sleep stages 1-3(min and %), arousal index (n/hr).

Timepoint [20] 438157 0
The outcome will be assessed at all study visits during the nap.
Secondary outcome [21] 438158 0
Sleep respiratory measures (tertiary outcome).
Assessment method [21] 438158 0
Respiratory measures will be assessed using a nasal airflow piece, an oximeter probe and respiratory bands. Metrics measured will be number of respiratory events in each sleep stage, apnea hypopnea index (number of events per hour) and oxygen desaturation index.
Timepoint [21] 438158 0
The outcome will be assessed at all study visits during the nap.
Secondary outcome [22] 438159 0
Sleep respiratory measures (tertiary outcome).
Assessment method [22] 438159 0
Respiratory measures will be assessed using a nasal airflow piece, an oximeter probe and respiratory bands. Metrics measured will be number of respiratory events in each sleep stage, apnea hypopnea index (number of events per hour) and oxygen desaturation index.
Timepoint [22] 438159 0
The outcome will be assessed at all study visits during the nap.
Secondary outcome [23] 438160 0
Actigraphy (tertiary outcome).
Assessment method [23] 438160 0
Actigraphy watches will be worn by participants for 3 weeks. Metrics calculated include sleep onset and offset timings, awakenings after sleep and sleep regularity.
Timepoint [23] 438160 0
The outcome will be assessed at all study visits during the nap.
Secondary outcome [24] 438161 0
Actigraphy (tertiary outcome).
Assessment method [24] 438161 0
Actigraphy watches will be worn by participants for 3 weeks. Metrics calculated include sleep onset and offset timings, awakenings after sleep and sleep regularity.
Timepoint [24] 438161 0
Actigraphy will be measured for 1 week prior to each of the 3 visits for 3 weeks in total.

Eligibility
Key inclusion criteria
Moderate to severe OSA (polysomnography (PSG) within 1 year with AHI greater than or equal to 15 or any night oximetry 3% ODI greater than or equal to 15), are fluent in English, are able to perform cognitive tasks are willing to provide informed consent and willingness to participate and comply with the study requirements.
Minimum age
40 Years
Maximum age
65 Years
Sex
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
Participants will be excluded if they;
• Have a history of head injury with associated loss of consciousness equal to or greater than 30 minutes;
• Have any current or previous diagnosis of psychiatric conditions (other than well managed affective disorders - beck depression inventory 2 score less than or equal to 19 and no current feelings of suicidality as determined by item 9, beck anxiety inventory score less than or equal to 15 severity);
• Have any diagnosis of a neurological disorder (e.g. Parkinson’s disease, epilepsy, multiple sclerosis);
• Have a diagnosis of cognitive impairment or dementia or a Mini-Mental State Examination Score less than 24
• Have a history of cerebrovascular events (e.g. stroke, TIA);
• Have any clinically significant comorbidity which will impede participation (as decided by the study doctor);
• Currently regularly use central nervous system active agents (e.g. cholinergic, anticonvulsant);
• Have a history of substance abuse or heavy alcohol use (greater than 10 standard drinks a week and greater than 4 standard drinks on any one day.);
• Are a current shift-worker or travel overseas within the last 2 weeks;
• Have previously used treatment for obstructive sleep apnea (e.g. CPAP) in the last 2 months;
• Are currently pregnant;
• Have a history of migraine;
• Have metallic implants including intracranial electrodes, surgical clips, shrapnel or a pacemaker;
• Have history of seizure;
• Have had adverse effects to previous brain stimulation methods;
• Previous adverse reaction to topical anaesthetic;
• Have a diagnosis of another primary sleep disorder (determined via medical screening or Insomnia Severity Index score greater than or equal to 12);
• Are unable to easily nap in the afternoon (determined by questionnaire).

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Allocation is concealed. A random sequence of intervention order will be generated on a computer by an independent researcher not involved in participant recruitment. The intervention will only be revealed to the researchers conducting the intervention after enrolment.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation using a randomisation table created by an independent investigator using computer software
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s

The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Crossover
Other design features
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis
Feasibility outcomes will be calculated using simple descriptive statistics.

Regional EEG data will be compared between frontal and sham, and parietal and sham conditions. Paired t-tests will be performed on matched EEG channels. The number of electrodes that reach significance (p<0.05) within the regions of interest (frontal and parietal), at an uncorrected level, will be reported. To compare within the regions of interest, qualitative analysis by visual review of active condition versus sham topographical heat maps will be performed.

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
NSW
Recruitment hospital [1] 26077 0
Woolcock Institute of Medical Research - Glebe
Recruitment postcode(s) [1] 41932 0
2037 - Glebe

Funding & Sponsors
Funding source category [1] 315653 0
Charities/Societies/Foundations
Name [1] 315653 0
Centre for Chronic Diseases of Ageing
Country [1] 315653 0
Australia
Primary sponsor type
Charities/Societies/Foundations
Name
Woolcock Institute of Medical Research
Country
Australia
Secondary sponsor category [1] 317977 0
None
Name [1] 317977 0
none
Country [1] 317977 0

Ethics approval
Ethics application status
Submitted, not yet approved
Ethics committee name [1] 314537 0
Sydney Local Health District Ethics Review Committee RPAH
Ethics committee address [1] 314537 0
Ethics committee country [1] 314537 0
Australia
Date submitted for ethics approval [1] 314537 0
29/01/2024
Approval date [1] 314537 0
Ethics approval number [1] 314537 0

Summary
Brief summary
Trial website
Public notes

Contacts
Principal investigator
Name 131934 0
Dr Angela D'Rozario
Address 131934 0
Dr. Angela D'Rozario, Woolcock Institute of Medical Research, 2 Innovation rd, Macquarie Park NSW 2113
Country 131934 0
Australia
Phone 131934 0
+610298053289
Fax 131934 0
Email 131934 0
angela.drozario@mq.edu.au
Contact person for public queries
Name 131935 0
Andrea Ricciardiello
Address 131935 0
Dr. Angela D'Rozario, Woolcock Institute of Medical Research, 2 Innovation rd, Macquarie Park NSW 2113
Country 131935 0
Australia
Phone 131935 0
+610298053289
Fax 131935 0
Email 131935 0
andrea.ricciardiello@woolcock.org.au
Contact person for scientific queries
Name 131936 0
Andrea Ricciardiello
Address 131936 0
Dr. Angela D'Rozario, Woolcock Institute of Medical Research, 2 Innovation rd, Macquarie Park NSW 2113
Country 131936 0
Australia
Phone 131936 0
+610298053289
Fax 131936 0
Email 131936 0
andrea.ricciardiello@woolcock.org.au

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment
Only de-identified processed data will be shared.


What supporting documents are/will be available?

No Supporting Document Provided



Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
No additional documents have been identified.