5-YEAR OUTCOMES IN TMD - RELATIONSHIP OF CHANGES IN PAIN TO CHANGES IN PHYSICAL AND PSYCHOLOGICAL VARIABLES

Factors influencing natural history and clinical course of pain in tem poromandibular disorders (TMD) are largely unknown. Physical, psycholo gical and behavioral data from a population-based epidemiologic study of TMD were examined in 234 cases of persons reporting TMD pain. The c ases were assigned to one of five pain pattern groups based on changes in average TMD pain from baseline to 5-year follow-up: (i) remitted ( 49% of the sample), (ii) high-improvement (14%), (iii) low-improvement (9%), (iv) same (13%), and (v) worse (16%). For each pain change grou p, an ANOVA-derived pattern analysis was performed to assess whether t he pattern of change in each of seven physical and three psychological variables was congruent or dissimilar to the pattern of change in ave rage pain intensity. For none of the physical or psychological variabl es was the change over time completely congruent with the changes in p ain. Changes in ambient average TMD pain were most closely related to those clinical variables whose assessment is influenced by pain or oth er self-reported symptoms (e.g., number of muscle sites painful to exa miner palpation), while the amount of pain change was less closely rel ated to changes in clinical variables, such as joint sounds, where ass essment is not dependent on subjective report. The three psychological variables, anxiety, depression, and somatization, displayed similar c hange patterns, but these patterns were distinctly different from thos e of the physical variables in that the remitted pain group was at the population mean at baseline for these psychological variables and rem ained there; significant improvement in psychological status was obser ved only in the pain group showing high improvement. The other three p ain change groups exhibited elevated psychological distress scores at both baseline and 5 years. These results indicate that although the re lationships among the course of pain, of physical variables, and of ps ychological variables are complicated, the 5-year outcome in pain is l argely independent of readily discernible changes in clinical signs. ( C) 1998 International Association for the Study of Pain. Published by Elsevier Science B.V.