Sleep Self-Regulation Using Mental Imagery

• Negative Sleep Habits [ Time Frame: Baseline and Final follow-up (at 21-days) ] [ Designated as safety issue: No ]
  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.
• Sleep Efficacy [ Time Frame: Baseline and final follow-up (at 21 days) ] [ Designated as safety issue: No ]
  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.
• Pre-Sleep Arousal [ Time Frame: Baseline and final follow-up (Day 21) ] [ Designated as safety issue: No ]
  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.
• Imagery Adherence [ Time Frame: Post-session, Daily, Final follow-up (21 days) ] [ Designated as safety issue: No ]
  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).
• Action Planning [ Time Frame: Baseline, Final follow-up (Day 21) ] [ Designated as safety issue: No ]
  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.

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.

Sleep deprivation is a significant health issue in the modern workplace. We conducted a randomized controlled trial to test the efficacy of techniques involving mental imagery promoting relaxation (arousal reduction; AR) and simulation of the appropriate sleep behavior in the likely environments (implementation intentions; II) in a population of daytime employees

• Sleep Deprivation
• Insomnia

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

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);

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