Testing the Insomnia Coach Mobile App With Veterans With Insomnia and PTSD

Insomnia Severity Index (ISI; Bastien et al., 2011)

A 7-item self-report questionnaire assessing the nature, severity, and impact of insomnia symptoms in the past month. Items are on a scale from 0 to 4. The seven answers are added up to get a total score, with higher scores reflecting greater insomnia severity

Pittsburgh Sleep Quality Index (PSQI; Buysse et al., 1989)

A 19-item self-report measure assessing qualities and problems associated with sleep in the past month. It generates seven component scores: subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleep medication, and daytime dysfunction. A global sleep quality score is obtained by summing the seven component scores. Higher scores reflect poorer sleep quality. The global score ranges from 0 to 21, with a cut-off score of 5 as distinguishing "good" sleepers from "poor" sleepers.

PROMIS-Sleep-Related Impairment (PROMIS-SRI; Buysse et al., 2010)

This 16-item self-report form assesses sleep-related impairment over the past seven days. Each question has five response options ranging in value from 1 to 5. To find the total raw score the values of the response to each question are summed. The raw scores are converted to a standardized T-score using conversion tables published on the PROMIS website (nihpromis.org), with higher scores indicating greater sleep/wake disturbances.

Generalized Anxiety Disorder - 7 Item (GAD-7; Spitzer et al., 2006)

This 7-item measure assesses anxiety symptom severity. Items are scored from zero to three. The whole scale score can range from 0 to 21 and cut-off scores for mild, moderate and severe anxiety symptoms are 5, 10 and 15 respectively.

Patient Health Questionnaire 8 (PHQ-8; Kroenke et al., 2009)

An 8-item self-report instrument used to assess depression severity. Since the scale is self-administered in our studies and further probing about positive responses is not feasible, the question about suicide from the PHQ-9 was removed. Items are scored 0 to 3, with the total score being the sum of the 8 items. Higher scores indicate greater depression severity, with a score of 10 or greater considered major depression, and scores of 20 or more is severe major depression.

Mobile Apps Rating Scale (MARS; Stoyanov et al., 2015)

A 20-item multidimensional, objective measure of app usability. It includes four subscales that measure an app's engagement, functionality, aesthetics, and information quality. All items are rated on a 5-point scale from "1. Inadequate" to "5. Excellent". The scores are tallied up and a mean score out of 5 is given to each of the categories scored.

System Usability Scale (SUS; Brooke, 1986)

A 10-item questionnaire of usability of products and services, including hardware, software, mobile devices, websites and applications. Items are on a 5-point scale numbered 1 to 5. Half of the items are worded negatively and half are worded positively. SUS yields a single number representing a composite measure of the overall usability of the system. To calculate the SUS score, the score contributions from each item are summed. Each item's score contribution will range from 0 to 4. For items 1,3,5,7,and 9 the score contribution is the scale position minus 1. For items 2,4,6,8 and 10, the contribution is 5 minus the scale position. Then the sum of the scores is multiplied by 2.5 to obtain the overall value of SU. SUS scores have a range of 0 to 100.