A Pilot Study of Cognitive Behavioral Therapy - Insomnia (CBT-I) Among Professional Firefighters

The Pittsburgh Sleep Quality Index (PSQI) is a self-report questionnaire designed to assess sleep quality and sleep disfunction throughout the previous month. Global scores range between 0-21 with higher scores indicating greater sleep dysfunction.

Fitbit Inspire HR wrist worn devices will be used to assess mean sleep patterns and sleep-related activity. The Fitbit Inspire HR may be worn consistently for up to 5-days and records wrist movement and heart rate variability to estimate sleep onset, waking, and sleep stages without need for the wearer to actively manipulate the device.

Feasibility will be measured via attendance, attrition rates, and completion of sleep diaries Participant weekly CBT-I attendance will be tracked and analyzed based upon average percentage of total number of sessions attended. Adherence to intervention components will be tracked via compliance with recommendations for the previous week. After each session, sleep diaries for that week will be examined by research assistants and recorded dichotomously as to whether "Yes, the participant was adherent" or "No, the participant was not adherent". An adherence percentage will be calculated.

Acceptability will be assessed using four self-report questions derived from similar studies, and calculated via mean acceptability ratings on a scale of 0-6. These items will include the degree to which the participant liked the program, whether they found the home practice/requirements reasonable, whether they would recommend the program, and whether they would take the program again in the future. Each item is responded to on a 7-point Likert-type scale ranging from 0 to 6, with higher scores indicating greater acceptability.

The Depression, Anxiety, Stress Scales 21-item measure (DASS-21) measures self-report ratings of depression, anxiety, stress symptoms. Items are responded to on a 4-point Likert-type scale ranging from 0 (Did not apply to me at all) and 3 (Applied to me very much or most of the time). Scores range between 0 and 120 for the DASS-21 total score. Higher scores indicate a greater severity of depression, anxiety, and stress.

The PTSD Checklist for DSM-5 (PCL-5) measures self-reported PTSD symptoms. Items are responded to on a 5-point Likert-type scale ranging between 0 (Not at all) to 4 (Extremely) with higher scores indicating greater severity of PTSD symptoms. Items are summed to create a total score ranging between 0-80 and scores greater than 33 indicate probable PTSD.

The Medical Outcomes Study 12-item Short-Form Survey (SF12v2) measures self-reported general health. The SF12v2 is a 12-item self-report that contains eight subscales: physical functioning, role-physical (i.e., role limitations related to physical health), bodily pain, general health, vitality, social functioning, role-emotional (i.e., emotional problems resulting in role limitations), and mental health. Higher scores indicate more favorable states of health.

The McMaster Family Assessment Device - General Functioning Scale (FAD-GFS) measures self-reported family functioning. The FAD-GFS is a 12-item self-report subscale of the larger 60-item FAD measure, that assesses overall health and pathology of the family. Items on the FAD-GFS are responded to on a 4-point Likert-type scale ranging between 1 (Strongly Agree) and 4 (Strongly Disagree). Higher total scores indicate more problematic family functioning.

The Psychomotor Vigilance Task (PVT) is a continuous performance task commonly used to objectively assess sleep-related cognitive deficits in vigilant attention. The PVT, administered remotely via Inquisit Web software (Millisecond Software LLC, US) will be used in this study. Inter-stimulus intervals are set to vary randomly between 2-10 seconds and subjects are to respond as quickly as possibly by clicking the mouse to stimuli flashed on the screen. Higher scores indicate slower response times and greater number of errors.

Fidelity will be assessed to ensure therapist adherence to the intervention protocol in each session. An adherence measure of covered session topics, covered activities, and global instructor skill in presenting material will be used to for each weekly session. Sessions will be audio recorded and two research assistants will independently rate each item regarding covered session topics and covered activities on a 3-point Likert-style scale ranging from 0-2 (0 = not present, 1 = somewhat present, 2 = fully present), and global instructor skill in presenting the material will also be rated on a 3-point Likert-style scale ranging from 0-2 (0 = none, 1 = minimal, 2 = adequate). Higher scores indicate better fidelity.