An Ecological Momentary Intervention for Mental Health in Individuals With Ankylosing Spondylitis

The recruitment rate will be calculated as the percentage of eligible participants who enroll in the study out of the total number of eligible participants

The retention rate will be calculated as the percentage of participants who completed the entire research process (including the follow-up) out of the initial recruitment

The dropout rate will be calculated as the percentage of participants who voluntarily withdrew from the study out of the initial recruitment number

Adherence rate will be measured using two indicators. First, for each momentary assessment, we will determine whether it has been answered (1 for answered, 0 for not answered). Second, adherence to the intervention will be assessed using the number of completed ecological momentary intervention interactive techniques.

The usability of the intervention will be evaluated using the System Usability Scale, a tool capable of assessing the usability of diverse technology-based applications. This scale comprises 10 questions rated on a five-point Likert scale ranging from "Strongly Disagree" to "Strongly Agree."

To assess program satisfaction, the Acceptability of the Intervention measure will be utilized. This four-item instrument utilizes a 5-point Likert scale (1=completely disagree; 5=completely agree). Higher scores indicate a greater acceptability of the intervention. Subsequently, ten participants will be selected for individual semi-structured interviews to gather insights regarding their experiences and perceptions of the ecological momentary intervention, the challenges encountered during the four weeks, and suggested improvements.

The depression and anxiety subscales of the Depression Anxiety Stress Scale-21 items will be employed to assess participants' levels of depression and anxiety. Each subscale comprises 7 items and evaluates negative emotional experiences and corresponding physiological responses over the past week. Higher scores indicate greater severity of negative affectivity, with responses rated on a 4-point Likert scale.

The stress subscale of the Depression Anxiety Stress Scale-21 items will be utilized to measure stress as a distinct construct. This subscale also consists of 7 items, which assess negative emotional experiences related to stressors encountered in the previous week. Similar to the depression and anxiety subscales, higher scores on the stress subscale reflect greater levels of stress experienced by participants.

The Visual Analogue Scale, a unidimensional tool for measuring pain intensity, will be utilized to assess patients' levels of pain. It has been widely applied across various adult populations for pain intensity evaluation. The scale consists of a 10-centimeter line on which patients mark their perceived pain intensity, with "no pain" at one end and "imagined worst pain" at the other. The distance from the "no pain" point to the participant's mark is then measured to determine the final score, which ranges from 0 to 10, with higher scores indicating greater pain intensity.

The Insomnia Severity Index, a patient-reported 7-item questionnaire, will be used to assess insomnia symptoms and their impact on daytime functioning. Each item is rated on a scale from 0 to 4, where 0 indicates no problem and 4 indicates a very severe problem, resulting in a total score that ranges from 0 to 28. Scores can be interpreted as follows: absence of insomnia (0-7), subthreshold insomnia (8-14), moderate insomnia (15-21), and severe insomnia (22-28).

The Brief Illness Perception Questionnaire will be utilized to assess cognitive and emotional representations of illness. The scale consists of eight items graded on a linear 0-10 response scale, with higher scores indicating a more threatening perception of the illness. Each item assesses a specific dimension of illness perception, including consequences, timeline, personal control, treatment control, illness identity, concern, coherence, and emotional representation. The ninth item, which is causal and involves an open-ended response, will be excluded from the analysis.

The Trait Coping Style Questionnaire will be employed to assess participants' coping strategies. This 20-item questionnaire includes two dimensions, positive and negative coping, scored on a five-point Likert scale. Higher scores in each dimension (ranging from 10 to 50) reflect a greater tendency to employ that specific coping style. The scale has demonstrated adequate reliability and validity.

The Short-Form 12-Item Version 2 will be employed to assess eight distinct health domains, evaluating both physical and mental health. Physical health-related domains include general health, physical functioning, role physical, and body pain. The mental health-related scales encompass vitality, social functioning, role, emotional health, and mental health. Scores on the Short-Form 12 Item Version 2 range from 0 to 100, with higher scores indicating better physical and mental health functioning.