The Effects of a Cognitive-Behavioral Treatment Program on
Transcription
The Effects of a Cognitive-Behavioral Treatment Program on
The Effects of a Cognitive-Behavioral Treatment Program on Temporo-Mandibular Pain and Dysfunction Syndrome HENDERIKUS J. STAM, PHD, PATRICIA A. MCGRATH, PHD, AND RALPH I. BROOKE, BCHD, FDSRCS, FRCD, MRCS Sixty-one patients clearly diagnosed as suffering from Temporo-Mandibular Pain and Dysfunction Syndrome (TMPDS) were randomly assigned to one of three groups, 1) hypnosis and cognitive coping skills, 2) relaxation and cognitive coping skills, or 3) a no-treatment control group. All patients were evaluated with a standard hypnotic susceptibility scale before treatment. The two treatment groups received four weekly sessions of their respective treatments. Patients in the hypnosis and relaxation groups reported equivalent decrements in pain, abnormal sounds in the temporomandibular joint, and limitations of jaw mobility. Hypnotic susceptibility was significantly correlated with reductions in reported pain for the treatment groups. Patients age and the duration of pain before treatment were not related to treatment outcome. Patients who dropped out of treatment had fewer limitations in jaw movement but did not differ in any other variable from patients who remained in treatment. These findings are discussed in relation to the hypothesis that Temporo-Mandibular Pain and Dysfunction Syndrome is stress-related muscular pain and dysfunction. Temporo-Mandibular Pain and Dysfunction Syndrome1 (TMPDS) is usually differentiated from other facial pains by the absence of clinical or radiographic evidence of organic changes in the tempo- 'TMPDS is the name proposed for this syndrome by the subcommittee on taxonomy of the International Association for the Study of Pain. It is frequently referred to as myofascial pain dysfunction syndrome in the dental literature to eliminate diagnoses involving known pathology in the temporomandibular joint (1-3). The term myofascial pain dysfunction syndrome, however, does not convey the fact that the syndrome is limited to the area of the temporomandibular joint. From the Department of Oral Medicine, University of Western Ontario, London, Ontario. Canada. Address requests for reprints to: Henderikus J. Stam, PhD, Department of Psychology, University of Calgary, Calgary, Alberta, Canada T2N 1N4. Received for publication July 6, 1983; revision received December 2, 1983. 534 romandibular joint and lack of tenderness in the condyles (2, 3). It is typically associated with three symptoms, namely pain and tenderness of the muscles of mastication and the temporomandibular joint, sounds during condylar movements (i.e., popping, clicking, or crepitus in the temporomandibular joint), and limitations of mandibular movements (4). TMPDS has been attributed to spasm in the muscles of mastication that may be mediated by physical or psychologic stress (3-8). Support for this hypothesis has come from several areas of research. First, pain that is similar in intensity and quality to TMPDS pain can be induced in healthy volunteers by vigorously thrusting the mandibles so that the lateral pterygoid muscles are hyperactivated (9). Second, TMPDS patients exhibit hyperactivity of the mandibular musculature (6, 8, 10, 11). Such hyperactivity Psychosomatic Medicine Vol. 46, No. 6 (Nov./Dec. 1984) Copyright © 1984 by the American Psychosomatic Society, Inc Published by Elsevier Science Publishing Co . Inc. 52 Vanderbilt Ave , New York. NY 10017 0033-3174/84/53.00 COGNITIVE-BEHAVIOR TREATMENT in these patients can be induced by stress (3,6,8, 10, 11, 12). Evidence that the muscle hyperactivity in TMPDS is related to psychologic stress comes from studies that have examined or induced stress in these patients (6, 8). These studies have found both elevated stress and psychophysiologic disorders in TMPDS patients. Although several methodologic problems may make these results equivocal, the hypothesis that stress-related muscular hyperactivity is responsible for TMPDS pain has led to the development of relaxation-based psychologic treatment programs. Both electromyographic (EMGj biofeedback and progressive muscular relaxation training have successfully led to decrements in pain and dysfunction (6, 8, 13-15). For example, Brooke and Stenn (15) compared 190 patients in four treatment groups: ultrasound, use of occlusal splint, relaxation training with biofeedback, and relaxation training without biofeedback. These authors concluded that relaxation training was as effective as other conservative methods of treatment and also produced the most rapid beneficial effect. Furthermore, at six months after treatment there were no significant differences in the percentage of successfully treated patients when relaxation training patients were compared with those who had received more than one treatment modality because of the failure of the first method. The exact mechanisms by which relaxation therapies come to reduce TMPDS symptoms are not known. It may be, however, that they aid in accentuating the relationship between muscle hyperactivity and stressful situations, thus leading to a more attentive monitoring of sensations and activity from the region of the temporomandibular joint. Consequently, the ha- bitual manner of coping with variables that precipitate and maintain the symptoms is altered. In this manner the effects of relaxation therapies may be cognitively mediated. Because cognitive-behavioral therapies have not been explicitly evaluated in the treatment of TMPDS, one purpose of the present study was to compare the effectiveness of cognitive pain control techniques in a no-treatment control procedure. Furthermore, the inclusion of a notreatment control procedure was also deemed important because there are reports in the literature that symptoms occasionally abate in the absence of treatment (6). However, no-treatment control groups are rarely used in TMPDS research. Hypnosis is often used as an adjuvant to relaxation-based therapies (16-19). In fact, the cognitive behavior therapies and the hypnotic situation have several variables in common (20). The most important of these is what is often referred to as "involved imagining" or the ability to become involved in and absorbed in one's imaginings (20-23). Most investigators of hypnosis agree that involvement in suggestion-related imaginings is closely related to responsiveness to suggestions or hypnotic susceptibility (20, 24). Furthermore, numerous clinical and laboratory studies of hypnotic and suggested analgesia have found a direct relationship between pain reductions and hypnotic susceptibility (25-28). Thus another purpose of the present study was to examine the predictiveness of hypnotic susceptibility for treatment outcomes in hypnotic and nonhypnotic treatment groups for chronic oral facial pain. Hypnotically suggested analgesia and suggestions for analgesia given in the absence of an hypnotic induction procedure typically result in equivalent reductions Psychosomatic Medicine Vol. 46, No. 6 (Nov./Dec. 1984) 535 H. J. STAM et al. in reported pain or equivalent increments METHODS in pain tolerance in between-subjects designs (25, 29, 30). When hypnotic analSubjects gesia is found to be superior to suggestions Sixty-one patients who had been referred to the alone as an analgesic, it is typically in expain clinic in the Department of Oral Medperiments using within-subjects designs oral-facial icine at the University of Western Ontario agreed to in which subjects are aware of the order take part in this study. They were diagnosed as sufof treatment (28). Stam and Spanos (31) fering from TMPDS on the basis of 1) lack of changes showed that the superiority of hypnotic or organic disease of either temporomandibular joint analgesia in such experiments was due to as determined by radiographs, 2) lack of tenderness the condyles on physical examination, and 3) the the carry-over effects of within-subjects of presence of at least one of the following symptoms: designs. Hypnotic analgesia was found to pain and tenderness of the muscles of mastication; be more effective, less effective, or equally sounds during condylar movements, mainly clickeffective as suggestions for analgesia alone, ing; and limitations of mandibular movements. Padepending upon the expectations induced tients ranged in age from 15 to 41 (M = 25.7 years, SD = 7), and 51 (84%) were women. The mean duby varying treatment order (31). ration of pain before treatment was 23 months Although these issues have been eval- (SD = 26); the median duration was 12 months. Fortyuated in the laboratory, few clinical stud- one patients completed the entire assessment, treaties have been conducted to evaluate the ment and follow-up sequence. The remaining 20 were classified As dropouts. efficacy of an hypnotic induction procedure in augmenting pain reductions beyond suggestions for analgesia alone. TypProcedure ically, investigators present hypnosis and A research assistant interviewed all patients in a suggestions and compare these to no treat- pretest session.1 Patients completed a multidimenment at all. For example, Reeves et al. (27) sional oral-facial pain questionnaire and were then studied two groups of cancer patients about tested on the Carleton University Responsiveness to to undergo painful hyperthermia treat- Suggestion Scale (CURSS) (32). The CURSS is a stanments with either hypnosis plus sugges- dardized, reliable, and valid scale of hypnotic susceptibility that yields three suggestibility scores for tions or no treatment. Although the highly each subject; 1) an objective score reflecting overt susceptible patients receiving hypnosis re- response to suggestion (CURSS : O), 2) a subjective ported less pain, it is not clear what as- score reflecting experiential response to suggestion pects of the treatment were responsible for (CURSS : S), and 3) an objective involuntariness score this reduction. A further purpose of the that reflects the extent to which objectively passed were experienced as occurring involunpresent experiment, then, was to compare responses tarily (CURSS : O-I). a group of patients who received hypnosis Each patient was tested individually. The assistant plus suggested cognitive strategies with a presented an hypnotic induction procedure orally, group that received relaxation training plus followed by the seven CURSS test suggestions and suggested cognitive strategies. This al- then the waking procedure. Patients self-scored their lowed us to assess whether the presence overt and subjective responses to each suggestion in of an hypnotic induction procedure and a booklet after the waking procedure. The CURSS : O the definition of treatment as hypnotherapy would increase treatment efficacy beyond that found in a relaxation training group. 'Thanks to Fran Cosier for conducting this session. 536 Psychosomatic Medicine Vol. 46, No, 6 (Nov./Dec. 1984) COGNITIVE-BEHAVIOR TREATMENT and 0-1 dimensions yielded scores ranging from 0 to 7 for each person; the CURSS : S dimension yielded a score ranging from 0 to 21 (32). Treatments. After their pretest session, patients were randomly assigned to one of three treatments with the exception that each group had approximately equivalent numbers of subjects with high, medium, and low susceptibility to hypnosis: hypnosis (n = 12), relaxation (n = 15), or waiting list control (WCL) (n = 14). The hypnosis and relaxation groups each received four weekly sessions of treatment beginning one week after their pretest session. The two treatments were identical with the exception that in the hypnosis group treatment was denned as hypnosis and each session was begun with a standard hynotic induction procedure. In the relaxation group, on the other hand, treatment was defined as relaxation; those subjects received standard progressive relaxation instructions at the outset of each session. The therapist was blind to patients' hypnotic susceptibility scores. The remainder of each session for both groups consisted of providing patients with coping skills to enable them to deal with painful episodes (33, 34). These consisted of attention diversion strategies, imagery training and imaginative reconstruction, and thought management or the reappraisal of pain-related thoughts and feelings. Specific strategies included focusing attention on details of the environment, focusing on cognitive processes, concentrating on activities, focusing on other, nonpainful sensations, imagining or recalling pleasant experiences, reinterpreting painful sensations, and encouraging positive self-statements (33, 34). Outcome Measures. After the pretest all patients had received a "daily pain log" consisting of seven 140-mm visual analog scales (VAS). Each scale was bounded by "no pain" on one end and "most intense pain imaginable" on the other. Patients were asked to make three marks daily along each line to indicate the intensity of their pain on awakening, during midday, and in the evening. Each mark was labelled for identification. All patients completed these logs throughout treatment until their fourth session. Aside from their function in assessing treatment efficacy, the logs were used to discuss and isolate situational variables that preceded or coincided with painful episodes. They also served to involve patients in the treatment process At the beginning of each treatment session, all patients rated the intensity of their pain, the frequency of any sounds in the temporomandibular joint, and the extent of limitations (if any) in opening their mouths on three 140-mm visual analogue scales. The actual extent to which the mouth could be opened was measured in millimeters with a caliper by the therapist. Two to four weeks after treatment, all patients were examined by the dental surgeon who had made the original diagnosis and who was blind to the patients' treatment status. After a physical examination the surgeon rated each of the three symptoms in terms of four categories, worse, same, improved, or completely alleviated. Waiting List Control Group. Patients assigned to the WLC group were seen for the pretest session and then returned four to six weeks later. At that time they were reexamined by the dental surgeon, who was blind to their treatment status. In the interval between examinations they were asked to complete the daily pain logs, which were returned after testing. All WLC group patients were then offered relaxation training. RESULTS One-way analyses of variance indicated that there were no differences between the groups on any of the dependent measures before treatment. Thus any posttreatment differences cannot be attributed to preexisting differences between the groups. Daily Logs All of the patients in the hypnosis and relaxation groups completed the logs and ten (71%) of the patients in the WLC group completed theirs. Before examining treatment efficacy, the time course of TMPDS was determined by examining the logs of the WLC group. Figure 1 depicts the daily ratings averaged for each week of the fourweek waiting period during which these ten patients kept records. A reliable pattern (as denned by at least 6 days in every week) emerged for seven of the ten WLC Psychosomatic Medicine Vol. 46, No. 6 (Nov./Dec. 1984) 537 H. J. STAM et al. Fig. 1. Mean rated pain in mm ( + SEM) presented by week and time of day and averaged across days from the daily logs of 10 waiting list control group patients. x weeks interaction, however, was significant, F(4, 68) = 2.51, p < 0.05 (covariate F[l, 33] = 174, p < 0.001). Newman-Keuls post hoc multiple comparisons on the adjusted means involved in the interaction (35) indicated 1) patients in the hypnosis and the WLC groups did not change significantly in peak pain across weeks, 2) patients in the relaxation group reported significant decrements in peak pain from the second to fourth week, and 3) relaxation group patients reported significantly less pain by the fourth week than did WLC group patients, whereas the hypnosis group did not differ from either the relaxation or WLC group in the fourth week. The means involved in this interaction are presented in Table I. 1 patients. As can be seen in Figure 1, pain Weekly Symptom Ratings was rated as mild (or not present) on awakening, increased by midday, and most sePain Intensity and Sounds in TMJ. At vere in the evening. Likewise, nine (75%) each of the four weekly visits, all treatment of the hypnosis group patients and ten (66%) of the patients in the relaxation group TABLE 1.. Mean Covariate and Adjusted Mean showed the same consistent pattern of Peak Pain Scores for the Treatment x Weeks change in reported painfulness within days. Interaction Thus, for most patients the most intense Treatment group pain was consistently experienced during Week Relaxation Hypnosis WLC later portions of the day. The data from the daily logs were re1a 50.9 61.6 51.3 2 48.1 a 48.6a 43.2 a duced by summing the greatest of the three 3 45.7 a 39.9 ab 50.7a daily pain reports during each week and 4 34.9 b 55.1, 44.8a dividing by seven. Thus, we obtained a n 12 15 10 "peak pain" score for each patient for each of four weeks, beginning with the week WLC = waiting list control. Means within each group sharing the same subscript do before the first treatment session. This first not differ significantly from each other, p < 0.05. week was then used as a covariate in a aCovariate. 3 x 3 mixed analysis of covariance (ANCOVA). The between-subjects variable was treatment group (three levels) and the "An identical ANCOVA on the mean weekly pain within-subjects variable was weeks (three scores for each subject led to similar results, with the levels). Neither of the main effects ap- exception, of course, that the means were lower than proached significance. The treatment those of the peak pain scores. 538 Psychosomatic Medicine Vol. 46, No. 6 (Nov./Dec. 1984) COGNITIVE-BEHAVIOR TREATMENT group patients had rated their subjectively experienced pain, sounds, and limitations of opening on the 140-mm VAS. The subjectively rated pain and sound measures were each subjected to a 2 x 3 mixed ANCOVA. The between-subjects variable was treatment (two levels) and the within-subjects variable was weeks (three levels). The first week was again used as the covariate. For the ANCOVA on pain, the only effect to achieve significance was the main effect for weeks, F (2, 50) = 7.17, p < 0.01, (covariate F[l,24] = 7.35, p < .05). Likewise, the only effect to approach significance for the ANCOVA on sounds was the main effect for weeks, F (2, 50) = 4.16 p < 0.05, (covariate F[l, 24] = 84.44, p < 0.001). The adjusted means for these main effects are presented in Table 2. Newman-Keuls post hoc multiple comparisons on the adjusted means for rated pain involved in the main effect for weeks indicated that both thirdand fourth-week ratings were significantly lower than second-week ratings. For rated sounds, the multiple comparisons indicated that fourth-week ratings were significantly lower than second-week ratings. Third-week ratings did not differ from second- or fourth-week ratings. TABLE 2. Mean Covariate and Adjusted Mean Weekly Rated Pain Intensity (VAS) and Rated Frequency of Sounds in the Temporomandibular Joint (VAS) for the Week's Main Effects Week Pain V 2 3 4 62.5 60.5a 42. % 38.6 b Sounds 66.7 60.9a 54.5ab 46.7b VAS = visual analogue scales. n = 27 for combined treatment groups. Means sharing the same subscript do not differ significantly from each other, p < 0.05. 'Covariate. Limitations of Mouth Opening. Eight patients in the hypnosis group (67%) and nine patients in the relaxation group (60%) had limitations in mouth opening at the start of treatment. For these patients, differences between the treatment groups in VAS-rated limitation of opening at any of the sessions were not significant as determined by t-tests (all ts < 1). However, the difference between the first and fourth session for all 17 patients combined was significant, t (16) = 3.02, p < 0.01. Thus, patients who reported having limitations in opening the jaw at the first session (M = 54.5, SD = 36) rated their limitations as significantly less at the fourth session (M = 29.1, SD = 33). Maximai Mouth Opening. Measurements of maximal mouth opening (in millimeters) for these same 17 patients were examined for differences between the treatment groups. There were no significant differences between the hypnosis and relaxation groups at any of the sessions (all ts < 1). The difference between the first and fourth session for the two groups combined was significant, t (16) = 2.39, p < 0.05. Maximal mouth opening in millimeters increased significantly from the first (M = 30.9, SD = 5.7) to the fourth session (M = 35.4, SD = 5.9). Posttreatment Evaluation To overcome the low frequencies in some of the cells for the following analyses, the posttreatment ratings by the dental surgeon were combined to form two categories, same or worse, and improved or completely alleviated. These are presented in Table 3. Pain. Chi-square analyses for the ratings of pain indicated a significant degree Psychosomatic Medicine Vol. 46, No. 6 (Nov./Dec. 1984) 539 H. I. STAM et al. TABLE 3. Frequencies of Posttreatment Physician Outcome Ratings of TMPDS Symptomatology Categories Croup Pain Hypnosis Relaxation WLC Sounds Hypnosis Relaxation WLC Limitations" Hypnosis Relaxation WLC Same or worse Improved or alleviated 5 3 10 7 12 4 7 6 11 5 9 3 2 2 9 6 7 3 TMPDS = temporomandibular pain and dysfunction; WLC = waiting list control. ^Limitation ratings are presented only for patients who had limitations of mouth opening at the time they entered the study. of association between treatment group and posttreatment pain, x2(2) = 7.81, p < 0.05. A separate x2 comparing the two treatment groups was nonsignificant, x2(l) = 1-49. The two treatment groups combined and compared with the WLC group, however, did result in a significant degree of association, x 2 (l) = 7.96, p < 0.01. Thus, the posttreatment pain of the two treatment groups was more likely to be rated as improved or alleviated than the ratings for the WLC group. Sounds. The rated presence of sound was not associated with treatment group, 2 X (2] = 4.44, NS. When the treatment groups are combined and compared to the WLC group the x2 is also nonsignificant, X2(l) = 3.52. Although a trend is present that is consistent with the remaining data, the overall relationship between treatment group and rated sounds is nonsignificant. 540 Limitation of Mouth Opening. For patients with limitation of mouth opening, rated limitations were significantly associated with treatment group, x2(2) = 7.55, p < 0.05. Further analyses indicated no differences between the two treatment groups alone, x2(l) < 1. whereas the combined treatment groups compared to the WLC group were significantly different, X2(l) = 7.53, p < 0.01. Like the pain ratings, posttreatment limitations in opening were more likely rated as improved or alleviated for treatment than no-treatment patients. Interrelationships of Outcome Measures The dependent measures for the two treatment groups were intercorrelated for each week of treatment. They were then converted using Fisher's Z-transformation, averaged, and converted back to correlation coefficients. The mean correlation coefficients for the four weeks are presented in Table 4. The only coefficients that were significantly greater than zero for each week of treatment were those relating peak pain and weekly rated pain. The other measures were weakly to moderately correlated and these correlations were not consistently significant. Thus it appears that there is some degree of independence among the various symptom measures. Hypnotic Susceptibility and Outcome Measures The peak pain scores, the weekly symptom ratings, and the maximal millimeters of mouth opening taken in the last week of treatment were subtracted from the same measures obtained in the first week of treatment. These difference scores and the Psychosomatic Medicine Vol. 46, No. 6 (Nov./Dec. 1984) COGNITIVE-BEHAVIOR TREATMENT TABLE 4. Mean Correlation Coefficients Relating Outcome Measures for Four Weeks of Treatment Peak pain Rated pain Rated sounds Rated limitations Peak pain Rated paina Rated sounds3 Rated limitations3 Limitation (mm) _ 0.57* _ 0.36 0.53 — 0.45 0.36 0.32 — -0.29 -0.22 -0.16 -0.38 n = 27. •"Weekly visual analogue scales ratings by patients. *AII four correlations significant, p < 0.05. posttreatment ratings of the dental surgeon (worse = 1, same = 2, improved = 3, alleviated = 4) were then correlated with the three measures of hypnotic susceptibility. They are presented in Table 5 separately for the combined treatment groups and the WLC group. The objective, subjective, and involuntariness measures of hypnotic susceptibility are highly and significantly correlated with the reduction in patients' peak pain scores and the posttreatment pain ratings. There are no significant correlations between measures of hypnotic susceptibility and TMPDS symptomatology for the WLC group, although these correlations are based on a small sample size. However, the difference scores based on the weekly pain ratings were not significantly related to any of the measures of hypnotic susceptibility. This may have been due to the relative instability of the global weekly ratings of pain versus the daily ratings obtained from the home logs. The correlation between the peak pain difference scores and the weekly rated pain difference scores was 0.51. Age and Duration of Pain Several reports have indicated that treatment effectiveness for TMPDS may be negatively related to both patients' age and the duration of pain before treatment (36, 37). Age and duration are included in Table 5 and do not correlate significantly with any of the outcome measures. Attrition Attrition was not related to any particular group. Patients were as likely to drop out of the WLC group (n = 7) as they were to drop out of the hypnosis (n = 6) or relaxation^ = 7) groups. Although there was a trend for patients who did not drop out of treatment to have a slightly longer duration of pain prior to treatment (M = 26.4 months, SD = 32) than dropouts (M = 15.8 months, SD = 21), this difference was not significant, t (59) = 1.34. Thirteen of the 20 dropouts had completed at least one treatment session. Their baseline levels of pain and subjective presence of sounds did not differ from those of subjects who did not drop out. However, only five of these 13 patients (38%) complained of interfering limitations in mouth opening, whereas 17 (63%) treatment group patients and 12 (86%) WLC group patients had done so. A comparison of dropouts with all other patients indicated that dropouts were significantly less likely to have limitations of mouth opening than those who completed Psychosomatic Medicine Vol. 46, No. 6 (Nov./Dec. 1984) 541 H. J. STAM et al. TABLE 5. Correlation Coefficients between Treatment Outcome Measures and Hypnotic Susceptibility Scales, Age, and Duration Difference Scores Peak pain Rated pain" Rated sounds3 Rated limitations8 Limitations (mm) Posttreatment ratings Pain Sounds Limitations CURSS.O CURSS:S CURSS:O-I Age Duration 0 60**(0.36) 0.19 0.25 0.36 -0.35 0.51"(0.19) -0.01 0.30 0.37 -0.52** 0.44*(-0.21) 0.15 0.33 0.46* -0.57" -0.28(-0.10) 0.12 -0.09 -0.15 0.19 -0.08(-0.28) -0.20 0.10 0.00 -0.15 -0.20(-0.35) 0.03(-0.09) 0.02(-0.39) 0.23I-0.36) -0.19(-0.27) 0.03(0.26) 0.54"(-0.05) -O.05(-0.09) 0.20(0.09) 0.58**(0.26) -0.04(0.07) -0.02(0.48) 0.58**(0.01) -0.09(-0.23) 0.00(0.32) CURSS = Carleton University Responsiveness to Suggestion Scale; WLC = waiting list control. Correlations in parentheses are for WLC group (n = 14; n = 10 for peak pain); all others are for combined treatment groups, n = 27. a Weekly visual analogue scales ratings by patients. *p < 0.05. •*p<0.01. all aspects of the study x2U) = 4.66, p < 0.05. A one-way analysis of variance on baseline VAS ratings of limitation comparing the hypnosis, relaxation, and dropout group approached significance (F (2, 37) = 3.14, p < 0.06). Post-hoc comparisons indicated that the dropouts were significantly lower in rated limitations of opening (M = 27) than those in the hypnosis (M = 61) or relaxation group (M = 48), who did not differ from each other. No other measure was able to predict whether or not a patient would remain in treatment. DISCUSSION Patients in both cognitive behavioral treatment groups reported less pain, lowered limitations in mouth opening, and a lower incidence of abnormal sounds from the first to fourth treatment session. Maximal mouth opening also increased over the course of treatment. Furthermore, the two treatment groups did not differ from each other on these measures. Neither did 542 they differ on the posttreatment ratings of the dental surgeon. However, both groups did differ from the WLC group on posttreatment pain and limitations. Although a similar trend was present for the posttreatment evaluation of sounds, this was not significant. This coincides with patients' reports that the presence of clicking or other sounds is often the last symptom to disappear (38). The peak pain scores indicated that the relaxation group was the only group to report reductions in daily ratings relative to the WLC group. Nevertheless, these groups did not differ when evaluated after treatment. The reasons for this finding are not immediately obvious. Overall, however, our brief treatment program provided significant reductions in TMPDS symptoms. Furthermore, these results are equivalent to those obtained in a previously tested larger group of TMPDS patients who underwent seven sessions of relaxation training with or without biofeedback in the same clinic (15). With the exception of the peak pain scores, the hypnosis and relaxation groups Psychosomatic Medicine Vol. 46, No. 6 (Nov./Dec. 1984) COGNITIVE-BEHAVIOR TREATMENT did not differ on any of the outcome measures. However, the reduction in peak pain and posttreatment examination ratings of pain were related to hypnotic susceptibility. This was true for all three measures obtained from the susceptibility scale. Laboratory studies of hypnotic analgesia have long demonstrated the importance of hypnotic susceptibility in predicting the efficacy of suggested analgesia (25, 26, 29-31, 39). This is true regardless of the presence or absence of a hypnotic induction procedure (30, 31). Several clinical studies have likewise noted the importance of hypnotic susceptibility in predicting the efficacy of hypnotic analgesia (27, 40). However, these studies have not evaluated the effects of the definition of the situation as hypnosis and the presence or absence of a hypnotic induction procedure. Our results indicated that hypnotic susceptibility was a good predictor of reductions in reported pain for both treatment groups. These results coincide well with laboratory studies that have found hypnotic susceptibility to be a good predictor of responsiveness to suggestions for analgesia in both hypnotized and nonhypnotized subjects. They also suggest that the skills that are critical for the efficacy of cognitively based behavior therapies for pain reduction may be the same skills that are critical determinants of hypnotic susceptibility, namely, involvement and absorption in one's imaginings. Absorption has also been implicated as an important predictor of the efficacy of electromyographic biofeedback for reducing muscle tension (41, 42). Quails and Sheehan (42) found that conditions that encouraged a withdrawal from the external environment (i.e., increased imaginative involvement) led to greater relaxation in high-absorption subjects than low-absorption subjects. The latter group showed greater relaxation with biofeedback than did highabsorption subjects. Thus, an important direction for future research on cognitive behavior therapies for pain reduction is the specification of the situational and person variables that most enhance internal, self-generated control. One limitation of the present study was the lack of a follow-up. Patients in the WLC group received relaxation training after the study and patients whose symptoms were the same or worse at the end of treatment were given the option of further treatment, usually physiotherapy. Thus any followup would have been severely limited in scope. It is also worth noting that, in the study conducted by Brooke and Stenn (15) on a large group of patients from the same clinic, the success of relaxation training at a 6-month follow-up was the same as success immediately after treatment. If these data are representative, then it is unlikely that a 6-month follow-up would have altered our results. An aspect of this study that is rarely addressed in the literature on TMPDS was the attempt to account for attrition. Unfortunately, almost none of our measures was able to discriminate between those who were likely to drop out and those who were likely to remain in treatment. The only exceptions were the measures of limitations in opening from the 13 patients who had completed at least one treatment session. Their lower level of limitation may have led these patients to decide they could deal with their TMPDS on their own once they had been diagnosed. Nevertheless, this is speculative and future studies should examine the nature of attrition from behaviorally based treatment programs more carefully. In summary, our study provides further evidence that relaxation-based psycho- Psychosomatic Medicine Vol. 46, No. 6 (Nov./Dec. 1984) 543 H. J. STAMetal. logic treatment programs are effective in treating TMPDS. Although the study does not provide direct support for the hypothesis' that stress-induced muscular hyperactivity is related to TMPDS, the success of psychologic therapies relative to more traditional conservative therapies (15, 43) is at least consistent with this hypothesis, By denning potential stress situations, instructing patients to monitor muscle ten- sion during and after stressful situations, and by providing relaxation therapy and coping strategies, we may reduce the contribution of the stress-hyperactivity cycle to TMPDS. 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