Table 2.
Applications of momentary data for pain research.
| Application | Pain experience variables* | Research question examples |
|---|---|---|
| Summarizing pain experiences over time | Average pain intensity†,6 | What is a participant's average pain level? |
| What are the between-person differences in average pain level? | ||
| Variability in pain intensity†,35 | What is participant's variability of pain level? | |
| What are the between-person differences in variability of pain levels? | ||
| Other summary measures (eg, maximum pain level, amount of time in pain, average pain after wake-up)†,40 | What proportion of time did the participant experience pain? | |
| What was the participant's maximum pain over the day? | ||
| How do participants differ in pain after waking up? | ||
| Modeling the effect of time on pain experience | Average starting level of pain†,20 | What is the participant's level of pain at the beginning of the investigation (eg, at the beginning of the EMA monitoring period, week, or day)? |
| How do patients differ in their level of pain at the beginning of the time scale under investigation (eg, at baseline in a clinical trial)? | ||
| Rate of change in pain level†‡,30,37 | How has the participant's pain level changed across the time scale under investigation (eg, over the course of the EMA monitoring period, over the week, or over the course of the day [ie, diurnal rhythm])? | |
| Modeling within-person processes | Concurrent or lagged effects29,34 | How does negative affect relate to pain levels and how does it predict changes in pain levels over time? |
| Individual's dynamic change in pain state42,49 | What is the short-term effect of a treatment decision on a patient's pain trajectory? | |
| How frequently does a patient oscillate between high and low pain states? | ||
| How long does a specific pain state persist? |
This table was adapted from the study by Bolger et al.1
*
Example studies are cited.
†
All these applications may be used to investigate within-person states and between-person differences.
‡
Primary application for EMA in clinical trials.
EMA, Ecological Momentary Assessment.