PRT for Chronic Low Back Pain

Recruitment feasibility will be assessed by the proportion of eligible participants who consent to participate in the study out of all individuals screened for eligibility.

Retention feasibility will be assessed by the proportion of randomized participants who complete the 3-month follow-up assessment (final study event).

Treatment adherence will be assessed by the number of intervention sessions attended by participants. Participants may attend up to 8 intervention sessions.

Participant satisfaction will be assessed using a post-intervention satisfaction survey evaluating participants' overall experience with the intervention. The questionnaire includes items assessing satisfaction, engagement, and perceived experience of the intervention they were assigned to. Response options use Likert-type scales, including: (1) frequency-based items rated as Always, Usually, Rarely, and (2) agreement-based items rated as Agree, Neutral, Disagree. Both scale options will be combined when assessed to report overall participant satisfaction.

For scoring purposes, responses will be coded numerically (e.g., Always/Agree = 3, Usually/Neutral = 2, Rarely/Disagree = 1), with higher total scores indicating greater satisfaction and acceptability of the intervention.

Acceptability of the intervention will be explored through a qualitative interview conducted with a randomly selected subset of 8 participants from the Pain Reprocessing Therapy (PRT) intervention group. Interviews will explore participants' overall impressions of the intervention, level of engagement, perceived benefits and limitations, barriers to participation, and suggestions for improvement.

Interviews will be transcribed verbatim, and analyzed using qualitative analysis to identify key patterns and themes related to intervention acceptability.

The Visual Analog Scale (VAS) measures pain intensity on a scale from 0 to 10, where 0 indicates no pain and 10 indicates the worst pain imaginable. Higher scores indicate greater pain intensity.

The Brief Pain Inventory (BPI) assesses the extent to which pain interferes with daily activities, mood, sleep, work, and relationships.

Participants rate each item using an 11-point numeric rating scale ranging from 0 to 10. A total interference score is calculated across items. Lower scores indicate less pain interference and higher scores indicate greater pain interference.

Perceived cause of pain will be assessed using a qualitative self-report question in which participants are asked to describe their beliefs about the cause(s) of their pain, providing up to three responses.

The Roland-Morris Disability Questionnaire (RMDQ) assesses disability related to low back pain. Scores range from 0 to 24, with higher scores indicating greater disability.

The Pittsburgh Sleep Quality Index (PSQI) assesses sleep quality over the previous month. Scores range from 0 to 21, with higher scores indicating poorer sleep quality.

The Patient Health Questionnaire-9 (PHQ-9) measures depressive symptoms. Scores range from 0 to 27, with higher scores indicating more severe depressive symptoms.

The Generalized Anxiety Disorder-7 (GAD-7) measures anxiety symptoms. Scores range from 0 to 21, with higher scores indicating more severe anxiety symptoms.

The work-related outcome question assesses self-reported return-to-work rates.

Physical activity and sleep will be measured using a wearable activity monitor. Outcomes include daily step count, sedentary and non-sedentary time, calories, overall activity levels, as well as total sleep time and sleep efficiency. Higher values indicate greater physical activity and better sleep quality.

The Six-Minute Walk Test measures the distance a participant can walk in six minutes. Greater walking distance indicates better functional capacity.

The Timed Up and Go test measures the time required to stand from a chair, walk a short distance, return, and sit down. Lower times indicate better functional mobility.

Pressure Pain Threshold assesses the minimum force applied to a stimulus that is perceived as painful. Higher thresholds indicate reduced pain sensitivity.

Temporal Summation asses the increase in pain perception in response to repetitive stimuli of constant intensity. Lower temporal summation indicates reduced central nervous system sensitization.

Wind-up ratio assesses pain responses to single versus repeated weighted pinprick stimuli. A lower wind-up ratio indicates reduced central sensitization.