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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Prospectively registered

Titles & IDs
Public title
Treatment of Obstructive Sleep Apnoea for Cognitive Decline in Mild Cognitive Impairment
Scientific title
Treatment with Continuous Positive Airway Pressure in people aged 50-80 years with Obstructive Sleep Apnoea and Mild Cognitive Impairment to reduce the rate of cognitive decline
Secondary ID [1] 284430 0
Nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Obstructive Sleep Apnea 291634 0
Mild Cognitive Impairment (MCI) 291635 0
Condition category
Condition code
Respiratory 292017 292017 0 0
Sleep apnoea
Neurological 292018 292018 0 0

Study type
Description of intervention(s) / exposure
The intervention being studied in this trial is Continuous Positive Airway
Pressure (CPAP), which is the current gold-standard treatment for Obstructive Sleep Apnea (OSA). CPAP involves wearing a mask around the nose, mouth or face, which is connected via a tube to a device that creates an internal air pressure. This air pressure is then transmitted through the tube at a continuous pressure and into the mask worn by the participant every night during sleep.
CPAP dose is set by the air pressure emitted from the mask, and this will be determined by a pressure determination sleep test performed at the
Woolcock Institute of Medical Research, in accordance with clinical practices. The duration of CPAP treatment will be for three months.

Compliance with treatment will be measured using the built-in CPAP smartcard that will measure how long (in hours) the CPAP pump was used by the patient each time it was switched on. This information will be assessed during compliance appointments with an experienced CPAP therapist at regular intervals throughout the treatment period.
Additionally, self-reported compliance will be assessed by a Study
Researcher during structured telephone interviews conducted at Weeks 1, 2, 4, 6, 8, 12, 13, 14, 16, 18, 20 and 24 during the active CPAP treatment period.
Intervention code [1] 289181 0
Treatment: Devices
Comparator / control treatment
No treatment.

This trial is a two-way cross-over design. Each treatment period will be three months duration, with a one-week wash-out period between the two treatment periods.
Control group

Primary outcome [1] 291906 0
Processing speed as assessed by Symbol Digit Modalities Test, and the Reaction Time Task component of the Cambridge Neuropsychological Test Automated Battery
Timepoint [1] 291906 0
Baseline, and once twelve weeks of each treatment period has been completed.
Primary outcome [2] 291907 0
Executive function as assessed by the Trails B and Stroop Test components of a standard Neuropsychological battery.
Timepoint [2] 291907 0
Baseline, and once twelve weeks of each treatment period has been completed.
Secondary outcome [1] 307791 0
Mood as assessed by Geriatric Depression Scale
Timepoint [1] 307791 0
Baseline, and once twelve weeks of each treatment period has been completed.
Secondary outcome [2] 307792 0
Sleep quality and daytime sleepiness as assessed by actigraphy and the Pittsburg Sleep Quality Index and Epworth Sleepiness Scale.
Timepoint [2] 307792 0
Baseline, and once twelve weeks of each treatment period has been completed.
Secondary outcome [3] 307793 0
Magnetic resonance spectroscopy markers of brain integrity.
Timepoint [3] 307793 0
Baseline, and once twelve weeks of the first treatment period has been completed.
Secondary outcome [4] 307857 0
Memory as assessed by the Rey Auditory Verbal Learning Test
Timepoint [4] 307857 0
Baseline, and once twelve weeks of each treatment period has been completed.

Key inclusion criteria
To be eligible, participants must:
1. Have the presence of at least moderate OSA as defined by an AHI of greater than or equal to 15 as defined by PSG using the criteria of 4% O2 desaturation for events.
2. Have a diagnosis of single-domain Mild Cognitive Impairment (MCI) as determined by neuropsychological examination using a standardized research neuropsychological battery.
3. Have stability of at least four weeks on permitted medications (i.e. medications known not to affect sleep architecture or circadian rhythms).
4. Be fluent in English
5. Be willing and able to complete baseline, three month and six month outcome measures
6. Be willing to send in CPAP Smartcard for adherence testing
Minimum age
50 Years
Maximum age
80 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Participants will be excluded if they have:
1. Suspected dementia or a score of <24 on the Mini-Mental State Examination
2. A history of cerebrovascular events (e.g., stroke, TIA)
3. Planned shift-work or transmeridian travel within timeline of study (six months from baseline)
4. A diagnosis of neurological disorders (e.g. Parkinson's Disease, Epilepsy, Multiple Sclerosis)
5. Head trauma with associated loss of consciousness > 30mins or head injury with persisting cognitive deficits
6. Psychiatric disorders including current major depression; Bipolar Disorder (I and II); schizophrenia
7. Been taking tricyclic antidepressants (TCAs), Monoamine Oxidase Inhibitors (MAOIs), benzodiazepines, sedative hypnotics, antipsychotics, mood stabilisers, modafinil or stimulants, cholinesterase inhibitors or medications known to affect sleep architecture and/or circadian rhythms (e.g. Lithium)
8. Current substance abuse or dependence (alcohol and/or other illicit substances)
9. Any significant systematic illness or medical condition that may hinder compliance with treatment protocol
10. Any current known conditions that may increase short-term risk from untreated OSA
11. Other known clinically significant sleep disorders (e.g. narcolepsy)
12. Been currently receiving CPAP or bi-level pressure for OSA
13. Requirements of oxygen or bi-level pressure during the CPAP titration PSG (PSG used to determine specifications for CPAP administration)

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Men and women aged 50-80 years will be referred from the Healthy Brain Ageing Clinic, Brain & Mind Research Institute and the Sleep Clinic, Woolcock Institute for Medical Research. Once informed consent is obtained, all baseline assessments are complete, and the Trial Coordinator along with a Trial Clinician has assessed eligibility and made the decision to enrol a participant, the Research Officer responsible for randomly allocating participants to treatment will be notified. Treatment allocation will be undertaken in accordance with the randomisation schedule which will be generated prior to trial commencement. The Research Officer, who will not have any involvement in the booking or conduct of assessments, will advise the participant of their allocated treatment group and next steps. The electronic randomisation schedule will be password protected and accessible only to the Research Officer responsible for treatment allocation.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Participants will be allocated to treatment using a randomly generated number sequence calculated used Research Randomizer ( prior to trial commencement. The fully replicable procedure will incorporate permuted blocks of varying lengths and will include stratification by OSA severity, with strata defined by a apnoea-hypopnoea index of < 30 or >= 30. Participants will be allocated to either CPAP Intervention-Control or Control-CPAP Intervention.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?

The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
This study is predominantly a pilot study to determine overall effect size to fund larger trials. It is estimated there will be 80% power to determine a medium to large effect size with this sample of 40 participants (and crossover design).
Primary analyses will be undertaken on an intention-to-treat basis. Outcome data will be analysed using repeated measures ANOVA. All analyses will be two-tailed with an alpha of 0.05.

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)

Funding & Sponsors
Funding source category [1] 289083 0
Name [1] 289083 0
Alzheimer's Australia
Address [1] 289083 0
Australia National Office
1 Frewin Place
Scullin ACT 2614
Country [1] 289083 0
Funding source category [2] 289122 0
Commercial sector/Industry
Name [2] 289122 0
ResMed Ltd
Address [2] 289122 0
1 Elizabeth Macarthur Dr, Bella Vista NSW 2153
Country [2] 289122 0
Primary sponsor type
University of Sydney
University of Sydney NSW 2006
Secondary sponsor category [1] 287770 0
Other Collaborative groups
Name [1] 287770 0
Woolcock Institute
Address [1] 287770 0
431 Glebe Point Road
Glebe NSW 2037
Country [1] 287770 0

Ethics approval
Ethics application status
Ethics committee name [1] 290872 0
University of Sydney Human Ethics
Ethics committee address [1] 290872 0
Margaret Telfer Building K07
University of Sydney NSW 2006
Ethics committee country [1] 290872 0
Date submitted for ethics approval [1] 290872 0
Approval date [1] 290872 0
Ethics approval number [1] 290872 0

Brief summary
Obstructive sleep apnoea (OSA), a sleep disorder that results in hypersomnia and sleep fragmentation, is identified as a possible risk factor for cognitive decline in the elderly. Although the occurrence of OSA in certain neurodegenerative disorders, particularly Alzheimer’s disease (AD), has been examined, its role and impact in patients with mild cognitive impairment (MCI) - a group 'at risk' of dementia progression - is yet to be established. Continuous positive airway pressure (CPAP) treatment has been shown to decrease sleep disturbance in patients with AD and OSA over periods of up to three weeks, and positive effects on global cognition, executive functioning and psychomotor speed have been observed. However, there are no known studies examining the efficacy of CPAP on cognition in MCI. Thus, if it is possible that OSA is identified and treated early, cognitive decline could be slowed or ameliorated.
We hypothesise that CPAP will be associated with superior cognitive functioning in the domains of processing speed, memory and executive function, than compared to no treatment with CPAP.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 47698 0
A/Prof Sharon Naismith
Address 47698 0
Level 5 Building F
94 Mallet Street
Camperdown NSW 2050
Country 47698 0
Phone 47698 0
+61 2 9351 0781
Fax 47698 0
Email 47698 0
Contact person for public queries
Name 47699 0
Mr Nathan Cross
Address 47699 0
Brain & Mind Research Institute
Level 3, Building M02F
94 Mallett St
Camperdown NSW 2050
Country 47699 0
Phone 47699 0
+61 2 9351 0762
Fax 47699 0
Email 47699 0
Contact person for scientific queries
Name 47700 0
Dr Zoe Terpening
Address 47700 0
Level 5 Building F
94 Mallet Street
Camperdown NSW 2050
Country 47700 0
Phone 47700 0
+61 2 9351 0750
Fax 47700 0
Email 47700 0

No information has been provided regarding IPD availability
Summary results
No Results