Background & Aims
The pain catastrophizing scale (PCS) is a measurement of the individual exaggerated negative orientation towards painful stimuli. It consists of 13 items divided in 3 dimensions; rumination (constant thinking about pain), magnification (exaggeration of the threat value of pain), and helplessness (perceived inability to control pain)1.
Operant conditioning is a trial-to-trial learning where behavior can be reinforced or extinct. Pain is part of 2 types of operant conditioning with pain avoidance and pain relief2–4.
The P3N3 component of the Event Related Potentials (ERP)s is an index of efficiency of cognitive processing5, and its amplitude has been found to be reduced in individuals with high levels of anxiety, worrying and depression6.
Since PCS has been associated with these symptoms, the aim is to investigate whether different levels of catastrophizing influence conflicting pain-related responses of reward/punishment by examining the P3N3.
Methods
29 participants filled the PCS and rated pain intensity induced by a cuff pressure on a VAS scale (0=no sensation, 10=worst pain, 5=pain threshold (PT)). The pressure was kept at PT during a cognitive task (repeating 5-word sentences with background noise to balance equally correct/incorrect responses). The experiment had 2 conditions: negative reinforcement with pain relief (VAS=3) as reward and unaltered pressure as punishment; and positive punishment with increased pain (VAS=7) as punishment and unaltered pressure as reward. Auditory feedback was given before the punishment/reward. Subjects did 120 trials in 3 sessions with 4 randomized blocks. EEG data from 64 channels were pre-processed with EEGlab. The ERPs were averaged over all trials and analyzed from -500 to +1000 ms post-auditory feedback and the P3N3 complex was identified. The subjects were divided in 2 groups using the median split of the PCS, rumination, magnification and helplessness scores. RM anova was performed.
Results
The P3N3 amplitude was higher in the group with rumination scores below the median (16.25±1.14µV) than the group with ruminations scores above the median (11.67±1.19µV; F=7.68, p=0.011). The P3N3 amplitude was higher/lower following correct answer (13.06±0.75µV) compared in incorrect answers (14.86±1.05µV; F=5.41, p=0.03). There P3N3 amplitudes were not significant difference between in the two conditions, nor were there significant two- or three-way interactions.
Conclusions
In conclusion, while no differences were found in early ERP complexes, a significant reduction in P3N3 peak-to-peak amplitude among catastrophizers suggested altered cognitive processing. Differential responses to operant conditioning further highlight the nuanced impact of pain catastrophizing on pain-related behaviors and coping mechanisms.
References
1. Sullivan M, Bishop S, Pivik J. The pain catastrophizing scale: User Manual. Psychol Assess. 1995;7(4):524-532. https://sullivan-painresearch.mcgill.ca/pdf/pcs/PCSManual_English.pdf%5Cnhttps://psycnet.apa.org/journals/pas/7/4/524/
2. Skinner BF. SCIENCE AND HUMAN. Published online 2014.
3. Ben Akpan TJK. Classical and Operant Conditioning—Ivan Pavlov; Burrhus Skinner. In: Science Education in Theory and Practice An Introductory Guide to Learning Theory. ; 2021:71-84.
4. Porreca F, Navratilova E. Reward, motivation, and emotion of pain and its relief. Pain. 2017;158(4):S43-S49. doi:10.1097/j.pain.0000000000000798
5. Polich John, P300 Clinical Utility and Control of Variability. Journal of Clinical Neurophysiology, 1998
6. Moretta T, Benvenuti SM. Familial risk for depression is associated with reduced P300 and late positive potential to affective stimuli and prolonged cardiac deceleration to unpleasant stimuli. Published online 2023:1-12.