​The International Association for the Study of Pain (IASP) defines pain as “an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage” (1). Pain is considered as a warning system for tissue damage. Pain is normal, but it is complex as well since it involves many thoughts and emotional contributions (2). Emotions, thoughts, beliefs and behaviours are important in pain and we need the brain to help us understand why these factors are important (2). These factors are related to context or environment and can be manipulated by yourself and/or others.

Thoughts about the expectation of pain may or may not cause this pain to occur or to increase. When expectations of hyperalgesia are suggested by a researcher or clinician or by previous experience, an increase in pain is registered (3-6). Contrary to the suggestion of hyperalgesia, a suggestion of hypo-algesia results in a decrease in registered pain (3, 4, 6). Furthermore, the assessment of expectations a priori seems to be a strong predictor of the analgesic process (3). These expectations are not only valid of experiencing pain, but also regarding the outcome of a treatment. It is suggested that the patient’s expectations of improvement at the start of a trial or treatment episode is a strong predictor of clinical improvement (5). This is confirmed for, among others, patients with chronic neck pain, low back pain and postoperative rehabilitation after total knee and total hip arthroplasties (7-9). When a neutral or positive message is provided to the patient regarding treatment outcome it may be beneficial for treatment outcome. Additionally, treatment failure early in the course of the disease will contribute to future expectations (5). Early effective treatments will result in an early expectation for improved functioning. Furthermore, it is important to assess patient expectations about the proposed treatment plan for the same reason as with the expectations of pain. The effect of the treatment plan can be predicted from the expectations of the patient. If the patient expects no effect of the proposed treatment plan, this issue should be addressed as part of the treatment plan, otherwise a successful outcome is difficult to achieve (5). It is even suggested that it would be more accurate to say that every (pain) treatment has a potential expectation component and some treatments (e.g. placebo) have primarily an expectation component (5).

Another factor that can be manipulated is attention or distraction. These factors are often related to each other. During distraction the attention is shifted away from pain or painful stimuli to stimuli that are more enjoyable (10). It seems that the more attentional resources used by distraction result in less resources available for pain (10). A high cognitive load with full attention to the task is necessary to effectively distract patients (11). Merely instructing patients to focus on another task is not sufficient (11). When healthy participants are distracted from the (laboratory or real-life) induced pain by e.g. a videogame or active continuous cognitive distraction, a positive effect on pain perception was found (12-14). The use of distraction (e.g. visual) in treatment programs may be beneficial for reducing pain in patients with burn injury (15, 16) and medical procedures (16), for improving emotional well-being of cancer patients (16) and for improving range of motion in patients with frozen shoulder (17). In chronic pain patients there is no evidence that distraction is beneficial for the decrease of pain (18).

For effective treatment in patients with pain it is important to consider expectations and attention or distraction before and/or during treatment. When considering and eventually modulating these factors treatment outcome might be more favourable.

Michel Mertens

Graduate and research assistant, Research Group MOVANT, Department of Rehabilitation Sciences and Physiotherapy (REVAKI), University of Antwerp, Wilrijk, Belgium

2020Pain in Motion

References and further reading:

1. Merskey H, Bogduk N. Classification of chronic pain. Descriptions of chronic pain syndromes and definitions of pain terms. 2nd ed. Seattle: IASP Press; 1994.

2. Butler D, Mosely L. Explain pain. Adelaide City West: Noigroup Publications; 2003.

3. Cormier S, Piche M, Rainville P. Expectations modulate heterotopic noxious counter-stimulation analgesia. The journal of pain : official journal of the American Pain Society. 2013;14(2):114-25.

4. Hanssen MM, Vancleef LM, Vlaeyen JW, Peters ML. More optimism, less pain! The influence of generalized and pain-specific expectations on experienced cold-pressor pain. Journal of behavioral medicine. 2014;37(1):47-58.

5. Fields HL. How expectations influence pain. Pain. 2018;159 Suppl 1:S3-s10.

6. Traxler J, Madden VJ, Moseley GL, Vlaeyen JWS. Modulating pain thresholds through classical conditioning. PeerJ. 2019;7:e6486.

7. Malfliet A, Lluch Girbés E, Pecos-Martin D, Gallego-Izquierdo T, Valera-Calero A. The Influence of Treatment Expectations on Clinical Outcomes and Cortisol Levels in Patients With Chronic Neck Pain: An Experimental Study. Pain practice : the official journal of World Institute of Pain. 2019;19(4):370-81.

8. Hayden JA, Wilson MN, Riley RD, Iles R, Pincus T, Ogilvie R. Individual recovery expectations and prognosis of outcomes in non-specific low back pain: prognostic factor review. The Cochrane database of systematic reviews. 2019;2019(11).

9. Tilbury C, Haanstra TM, Verdegaal SHM, Nelissen R, de Vet HCW, Vliet Vlieland TPM, et al. Patients' pre-operative general and specific outcome expectations predict postoperative pain and function after total knee and total hip arthroplasties. Scandinavian journal of pain. 2018;18(3):457-66.

10. Birnie KA, Chambers CT, Spellman CM. Mechanisms of distraction in acute pain perception and modulation. Pain. 2017;158(6):1012-3.

11. Lavie N. Distracted and Confused?: Selective Attention Under Load. Trends in cognitive sciences. 2005;9:75-82.

12. Zeroth JA, Dahlquist LM, Foxen-Craft EC. The effects of auditory background noise and virtual reality technology on video game distraction analgesia. Scandinavian journal of pain. 2019;19(1):207-17.

13. Volz MS, Suarez-Contreras V, Portilla AL, Fregni F. Mental imagery-induced attention modulates pain perception and cortical excitability. BMC Neurosci. 2015;16:15.

14. Moont R, Pud D, Sprecher E, Sharvit G, Yarnitsky D. 'Pain inhibits pain' mechanisms: Is pain modulation simply due to distraction? Pain. 2010;150(1):113-20.

15. Malloy KM, Milling LS. The effectiveness of virtual reality distraction for pain reduction: a systematic review. Clin Psychol Rev. 2010;30(8):1011-8.

16. Indovina P, Barone D, Gallo L, Chirico A, De Pietro G, Giordano A. Virtual Reality as a Distraction Intervention to Relieve Pain and Distress During Medical Procedures: A Comprehensive Literature Review. Clin J Pain. 2018;34(9):858-77.

17. Huang ML, SH; Yeh, SC; Chan, RC; Rizzo, A; Xu, W; Han-Lin, W; Shan-Hui, L. Intelligent Frozen Shoulder Rehabilitation. IEEE Intelligent Systems. 2014;29(3):22-8.

18. Van Ryckeghem DM, Van Damme S, Eccleston C, Crombez G. The efficacy of attentional distraction and sensory monitoring in chronic pain patients: A meta-analysis. Clin Psychol Rev. 2018;59:16-29.