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Registration number
Ethics application status
Date submitted
Date registered
Date last updated

Titles & IDs
Public title
Sleep Self-Regulation Using Mental Imagery
Scientific title
Using Mental Imagery to Deliver Self-Regulation Techniques That Target Sleep Initiation Behaviors and Pre-Sleep Arousal
Secondary ID [1] 0 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Sleep Deprivation 0 0
Insomnia 0 0
Condition category
Condition code
Neurological 0 0 0 0
Other neurological disorders
Mental Health 0 0 0 0
Other mental health disorders

Study type
Description of intervention(s) / exposure
Behaviour - Sleep Self-Regulation Using Mental Imagery

Active Comparator: Arousal reduction using guided imagery - Sleep Self-Regulation Using Mental Imagery: Participants in the arousal reduction condition were instructed to imagine wearing a backpack loaded with their worries, then putting the heavy backpack down, and then experiencing the relief and freedom from tension.

Active Comparator: Mental simulation of sleep behavior - Sleep Self-Regulation Using Mental Imagery: Participants in this condition received instructions to visualize a specific behavioral plan designed to meet the goal of obtaining quality sleep each night through the practice of certain behaviors. To form the behavioral plan, participants visualised changing into comfortable clothes and taking time to relax prior to going to bed, the time they planned to go to sleep, where they planned to sleep, and the bedtime routine they follow to help them to get to sleep. At bedtime, they were instructed to mentally run through a checklist of these behaviors and then do any behaviors that they had not yet completed.

Active Comparator: Combination - Sleep Self-Regulation Using Mental Imagery: Participants in this condition were asked to practice a combination of the guided imagery (for relaxation) and mental simulation imagery for sleep-related behaviour

Sham Comparator: Control - Sleep Self-Regulation Using Mental Imagery: Participants in this condition were asked to imagine a typical post work activity

Behaviour: Sleep Self-Regulation Using Mental Imagery
Comparison of two forms of mental imagery to instigate behaviors that assist in the sleeping process

Intervention code [1] 0 0
Comparator / control treatment
Control group

Primary outcome [1] 0 0
Sleep Quality - Assessed using the Pittsburgh Sleep Quality Index (PSQI; Buysse et al, 1989).The PSQI includes 19 items that assess sleep quality, hours of sleep, sleep onset length, sleep efficiency, sleep disturbances, use of medication and daytime. Item ratings are recoded and combined to form seven component scores. These scores are then summed into a global score ranging from 0(no difficulty) to 21(severe difficulties in all areas). Daily sleep quality was assessed with five PSQI items.
Timepoint [1] 0 0
Baseline and at 3 weeks. Data will also be presented for every day for the duration of the 3 week period so change can be reported.
Secondary outcome [1] 0 0
Negative Sleep Habits - The Sleep Hygiene Index (Mastin et al, 2006). Respondents rate on a scale from 1 (never) to 5 (all the time) how frequently they engaged in 13 behaviors (e.g. "I take naps lasting two or more hours"). Ratings were summed to provide a total negative sleep habit frequency score.
Timepoint [1] 0 0
Baseline and Final follow-up (at 21-days)
Secondary outcome [2] 0 0
Sleep Efficacy - Participants rated their sleep self-efficacy with the item, "how confident are you that you can take the actions necessary to get a good sleep tonight?" Sleep response efficacy was rated with the item "how confident are you that you will actually get a good sleep tonight?" ratings ranged from 1 (not at all confident) to 10 (very confident), and they were summed; r=.69, p<.01 at baseline and r=.20, p<.05 at final follow-up.
Timepoint [2] 0 0
Baseline and final follow-up (at 21 days)
Secondary outcome [3] 0 0
Pre-Sleep Arousal - The Pre-sleep Arousal Scale (Nicasso et al, 1985) includes an 8-item somatic subscale (e.g. "how often in the last week before bed have you had a tight, tense feeling in your muscles?") and an 8-item cognitive subscale (e.g. "how often in the last week before bed do you review or ponder events of the day?"). Ratings range from 1 (not at all) to 5 (extremely) and are summed to generate scores.
Timepoint [3] 0 0
Baseline and final follow-up (Day 21)
Secondary outcome [4] 0 0
Imagery Adherence - Measure adapted from the Vividness of Imagery Questionnaire (White et al, 1978). Participants rated the vividness of the following images: (1) putting things into a bag, (2) releasing a bag, (3) getting home from work, (4) relaxing at home, (5) their night-time routine, (6) the time that they visualised going to bed, (7) the environment of their bedroom, (8) the details of the bed they are sleeping in, (9) the image of themselves falling asleep. Response options were: 1 (no image at all) 2 (vague and dim), 3 (somewhat vivid), 4 (reasonably clear), and 5 (perfectly clear and vivid).
Timepoint [4] 0 0
Post-session, Daily, Final follow-up (21 days)
Secondary outcome [5] 0 0
Action Planning - An adaptation of the action planning measure developed by Luszczynska and Schwarzer (2003) was used. The items included: "I have made a detailed plan for (1) how I am going to wind down before going to sleep (2) how I am going to prepare for bed (3) how I am going to prepare the place where I will sleep, and (4) the time when I go to sleep". Responses ranged from 1 (not at all) to 7 (very much); ratings were summed to generate scores.
Timepoint [5] 0 0
Baseline, Final follow-up (Day 21)

Key inclusion criteria
- ability to read and write in English;

- full-time employment;

- work shifts during daytime hours (i.e., participants were excluded if they worked
night shifts either through the organization or through a secondary job) in a position
that provided daily access to email;

- a score of five or greater on the Pittsburgh Sleep Quality Inventory (PSQI) which
indicates at least moderate difficulties in two or more areas (e.g., sleep quality and
daytime dysfunction);
Minimum age
18 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
- An identifiable biological cause of current sleep deprivation (e.g., sleep apnoea,
narcolepsy, restless leg syndrome, periodic limb movement disorder, or pregnancy)

- An identified psychological disorder

- Caring for a child under the age of 5 or have a reason outside of work that caused
them to regularly lack sleep.

- Incomplete data (over 50% of daily data missing or missing final follow-up assessment

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s

The people analysing the results/data
Intervention assignment
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis

Recruitment status
Data analysis
Reason for early stopping/withdrawal
Other reasons
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)
Recruitment outside Australia
Country [1] 0 0
New Zealand
State/province [1] 0 0

Funding & Sponsors
Primary sponsor type
University of Auckland, New Zealand

Ethics approval
Ethics application status

Brief summary
This randomised controlled trial assessed the efficacy of four mental imagery techniques for
improving sleep and its related behaviour: (1) imagery focused on reducing arousal levels;
(2) imagery incorporating implementation intentions (a strategy designed to link specified
behaviour with the anticipated context) for sleep-related behaviour; (3) a combination of
imagery using arousal reduction and implementation intention strategies; or (4) a condition
where participants were asked to imagine their typical post work activities.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 0 0
Marisa H Loft, PhD
Address 0 0
Monash University (Sunway Campus, Malaysia)
Country 0 0
Phone 0 0
Fax 0 0
Email 0 0
Contact person for public queries
Name 0 0
Address 0 0
Country 0 0
Phone 0 0
Fax 0 0
Email 0 0
Contact person for scientific queries

Summary results
Other publications