MEMORIES OF CHRONIC PAIN AND PERCEPTIONS OF RELIEF

Clinicians and researchers often ask patients to remember their past p ain. They also use patient's reports of relief from pain as evidence o f treatment efficacy, assuming that relief represents the difference b etween pretreatment pain and present pain. We have estimated the accur acy of remembering pain and described the relationship between remembe red pain, changes in pain levels and reports of relief during treatmen t. During a 10-week randomized controlled clinical trial on the effect iveness of oral appliances for the management of chronic myalgia of th e jaw muscles, subjects recalled their pretreatment pain and rated the ir present pain and perceived relief. Multiple regression analysis and repeated measures analyses of variance (ANOVA) were used for data ana lysis. Memory of the pretreatment pain was inaccurate and the errors i n recall got significantly worse with the passage of time (P < 0.001). Accuracy of recall for pretreatment pain depended on the level of pai n before treatment (P < 0.001): subjects with low pretreatment pain ex aggerated its intensity afterwards, while it was underestimated by tho se with the highest pretreatment pain. Memory of pretreatment pain was also dependent on the level of pain at the moment of recall (P < 0.00 1). Ratings of relief increased over time (P < 0.001), and were depend ent on both present and remembered pain (Ps < 0.001). However, true ch anges in pain were not significantly related to relief scores (P = 0.4 1). Finally, almost all patients reported relief, even those whose pai n had increased. These results suggest that reports of perceived relie f do not necessarily reflect true changes in pain. (C) 1998 Internatio nal Association for the Study of Pain. Published by Elsevier Science B .V.