App-delivered Sleep ThERapy for Older Individuals With Insomnia

Insomnia Severity Index (ISI) is a 7-item questionnaire used to examine overall insomnia severity. It consists of a five-point Likert type scale for each item (ranging from "no problem" = 0 to "severe problem" = 4) regarding symptoms over the past 2 weeks. Scores range from 0-28 with higher scores indicating greater insomnia symptom severity.

Subjective sleep quality will be determined from the Pittsburgh Sleep Quality Index Score (PSQI) - a 19-item questionnaire with seven component scores derived from the responses, each scored 0 (no difficulty) to 3 (severe difficulty). The component scores are summed to produce a global score (range 0-21) where a score of 5 or more indicates poor sleep quality.

Sleep onset latency will be determined from the Pittsburgh Sleep Quality Index Score (PSQI) - a 19-item questionnaire with a total score range of 0 to 21 with scores greater than 5 indicating poor sleep quality. A single item will be used to assess sleep onset latency over the last 2 weeks.

Wake after sleep onset will be determined from the Pittsburgh Sleep Quality Index Score (PSQI) - a 19-item questionnaire with a total score range of 0 to 21 with scores greater than 5 indicating poor sleep quality. A single item will be used to assess wake after sleep onset over the last 2 weeks.

Total sleep time will be determined from the Pittsburgh Sleep Quality Index Score (PSQI) - a 19-item questionnaire with a total score range of 0 to 21 with scores greater than 5 indicating poor sleep quality. A single item will be used to assess total sleep time over the last 2 weeks.

The Flinders Fatigue Scale (FFS) is a 7-item self-reported instrument designed to measure the level of subjective daytime fatigue experienced over the previous two weeks. 6-items consist of a 5-point Likert type scale ranging from "not at all" = 0 to "extremely" = 4. Item 5 uses a multiple-item checklist and is scored as a sum. All items are summed with total scores ranging from 0-31 with higher scores reflecting greater fatigue.

The Epworth Sleepiness Scale (ESS) is an 8-item self-reported questionnaire that provides a rating of general sleepiness over the last 2 weeks using a 4-point likert scale from "would never dose" = 0 to "high chance of dozing" = 3. All items are summed with total scores ranging from 0-26 where scores >10 indicating above-average daytime sleepiness.

The EuroQol five-dimensional (EQ-5D) is a self-reported questionnaire which assesses 5 dimensions of mobility, self-care, usual activities, pain/discomfort and anxiety/depression and overall health. The 5 dimensions range from "1 = indicating no problem" - "5 = indicating unable to/extreme problems" and the overall score from 0 (worst health state imaginable) to 100 (best health state imaginable).

The Patient Health Questionnaire-9 is a 9-item self-reported measure of depressive symptoms over the past 2 weeks. Scores for each question (Likert type scale "not at all" = 0 to "nearly every day" = 3) sum to a total score out of 27 with higher scores reflecting severe depressive symptoms.

The General Anxiety Disorder-7 (GAD-7) is a 7-item self-administered scale used to assess the severity of generalised anxiety over the previous 2 weeks. It consists of a three-point Likert type scale for each item (ranging from "not at all" = 0 to "nearly every day" = 3). All items are summed with total scores ranging from 0-21 where 5, 10 and 15 indicate the cut-off scores for mild, moderate and severe anxiety, respectively.

The British Columbia Cognitive Complaints Inventory (BC-CCI) is a 6-item tool to assess self-perceived cognition. It explores any perceived problems associated with cognition, memory, expressing thoughts, word finding, slow thinking, and difficulty solving problems in reflection of the last 7 days. Answers for each question range from 0 (= "not at all") to 3 (= "Very much"). Scores are summed to a total out of 18 that reflects the cognitive complaint severity.

To determine if there is a relationship between therapeutic outcome (Insomnia Severity Index, ISI) and engagement (number of in-app sleep diary entries for study completers)

Digital health literacy will be assessed using the eHEALS Literacy Scale (eHEALS) which is an 8-item, 5-point Likert-type questionnaire that measures a participant's perception of, and ability toward electronic health information. Responses range from "strongly disagree" =1, to "strongly agree" = 5. Total scores are summed to range from 8 to 40 where lower scores indicate lower self-reported digital health literacy.

The moderating effect of the baseline digital health literacy on therapeutic outcomes (ISI scores) and engagement (number of daily sleep diary entries) will be assessed.