Mechanisms Underlying Pain Avoidance in Complex Regional Pain Syndrome

Area of Science:

• Neuroscience
• Psychology
• Pain Research

Background:

• Maladaptive pain avoidance is crucial in chronic pain, particularly in complex regional pain syndrome (CRPS).
• Instrumental pain avoidance mechanisms in CRPS are not well understood.
• Identifying these mechanisms can inform better interventions for CRPS patients.

Purpose of the Study:

• To investigate the mechanisms of maladaptive pain avoidance in complex regional pain syndrome (CRPS).
• To compare avoidance learning and decision-making in CRPS patients versus healthy controls (HC).
• To explore the neural correlates, specifically resting-state alpha activity, of pain avoidance in CRPS.

Main Methods:

• An instrumental pain avoidance task was administered to 28 CRPS patients and 27 HC participants.
• Reinforcement learning models assessed threat/safety learning and decision-making.
• Resting-state magnetoencephalography quantified prefrontal alpha-band activity.

Main Results:

• CRPS patients demonstrated elevated threat and safety learning compared to HC, with increased choice stochasticity.
• Pain expectancies influenced avoidance decisions less strongly in CRPS patients than in HC.
• Reduced prefrontal alpha power and increased anxiety were linked to heightened threat learning in CRPS.

Conclusions:

• CRPS patients exhibit enhanced learning from recent outcomes and diminished expectancy-guided behavioral control.
• Prefrontal alpha activity partially mediates the impact of pain severity on threat learning in CRPS.
• Findings suggest novel targets for psychosocial and neuromodulatory interventions in CRPS treatment.