Morning Bright Light Treatment for Chronic Low Back Pain: Potential Impact on the Volatility of Pain, Mood, Function, and Sleep

Abstract

Objectives Most treatment outcome studies for people with chronic low back pain (CLBP) have based analyses on and reported only the mean levels of these factors. However, high levels of pain, mood, function, and sleep volatility may represent unique factors contributing to diminished quality of life. Our goal was to determine whether bright light treatment affected both mean levels of pain, mood, function, and sleep and reduced volatility in these outcomes. Methods US military veterans with CLBP (N = 22) underwent an open trial with a seven-day baseline, followed by 13 days of a one-hour morning bright light treatment self-administered at their home and a 30-day follow-up. Participants completed daily diary measures at 12 Pm and 6 Pm every day during the three study epochs. Results Using location scale modeling, results suggested that, in addition to being associated with changes in mean levels of pain intensity, pain interference, negative affect, and sleep quality, bright light treatment was also related to reductions in the volatility of pain intensity and negative affect, reductions that were largely maintained during follow-up. Conclusions Changes in mean levels and volatility were independent factors, suggesting that bright light treatment was related to participants experiencing fewer “pain flares.” These findings underscore the potential importance of volatility as a future treatment target.

The role of affect in chronic pain: A systematic review of within-person symptom dynamics

“…Consistent with these findings, greater within-person variability in NA (as defined by within-person standard deviation) was associated with increased severity of NA among two studies of chronic back pain patients [78,79]. Similarly, greater variability in pain was associated with worse pain severity [79,80]. However, there was mixed evidence of cross-over in these effects.…”

“…Evidence from the mood disorders literature suggests individuals who experience wider variability in NA also tend to experience worse depressive symptoms and poorer psychological well-being [74][75][76][77]. Consistent with these findings, greater within-person variability in NA (as defined by within-person standard deviation) was associated with increased severity of NA among two studies of chronic back pain patients [78,79]. Similarly, greater variability in pain was associated with worse pain severity [79,80].…”

“…However, there was mixed evidence of cross-over in these effects. That is, variability in affect was associated with pain intensity or vice versa in some studies [78,81], and not in others PAIN AND AFFECT 14 [79,80]. When taking temporal relationships into account, instability of NA (i.e., the tendency to experience unusually large and/or frequent changes in affect) was associated with higher pain severity and disability [82,83].…”

“…When taking temporal relationships into account, instability of NA (i.e., the tendency to experience unusually large and/or frequent changes in affect) was associated with higher pain severity and disability [82,83]. In one study, both mean levels and variability in pain and NA were lower after bright light treatment to improve sleep [79].…”

“…Finally, idiographic and multi-level models that characterize within-person relationships between pain and affect may be helpful in identifying mechanisms involved in the successful treatment of co-occurring pain and emotional symptoms. EMA approaches have previously been integrated into chronic pain treatment protocols to assess outcomes [79,[104][105][106]. However, these studies focused on the impact of treatment on mean levels of symptoms, rather than PAIN AND AFFECT 21 changes in relationships between symptoms.…”