To develop criteria for the classification of fibromyalgia, we studied 558 consecutive patients: 293 patients with fibromyalgia and 265 control patients. Interviews and examinations were performed by trained, blinded assessors. Control patients for the group with primary fibromyalgia were matched for age and sex, and limited to patients with disorders that could be confused with primary fibromyalgia. Control patients for the group with secondary-concomitant fibromyalgia were matched for age, sex, and concomitant rheumatic disorders. Widespread pain (axial plus upper and lower segment plus left-and right-sided pain) was found in 97.6% of all patients with fibromyalgia and in 69.1% of all control patients. The combination of widespread pain and mild or greater tenderness in 2 11 of 18 tender point sites yielded a sensitivity of 88.4% and a specificity of 81

The hypervigilance model of pain perception states that chronic pain patients have a heightened sensitivity to pain (e.g. low threshold and tolerance) because of increased attention to external stimulation and a preoccupation with pain sensations. This study tested the hypothesis that individuals with fibromyalgia, a chronic pain disorder of undetermined origin, have a generalized hypervigilant pattern of responding that extends beyond the pain domain. Twenty fibromyalgia out-patients, 20 rheumatoid arthritis (RA) patients, and 20 normal controls served as subjects. The RA and normal control subjects were age and sex matched to the fibromyalgia patients. Subjects were tested for pain tolerance, pain threshold, and noise tolerance and were asked to complete a number of questionnaires that assessed hypervigilance. As predicted, the responses of the fibromyalgia patients to both the pain and auditory stimuli were consistent with the generalized hypervigilance hypothesis. These patients had significantly lower threshold and tolerance values than the RA patients, who in turn, had lower values than the normal control subjects. The results of the psychological questionnaires revealed that the fibromyalgia and RA patients preferred lower levels of external stimulation than the control subjects. The outcome of this study supports the generalized hypervigilance hypothesis, suggesting that fibromyalgia patients have a perceptual style of amplification. The implications of these findings for understanding the role of biological, cognitive, and perceptual factors in pain disorders are discussed.

Forty-two patients with primary fibromyalgia were randomized into a 20-week program consisting of either cardiovascular fitness (CVR) training or simple flexibility exercises (FLEX) that did not lead to enhanced cardiovascular fitness. Patients were supervised by the same medical fitness instructors. Patients in neither group had contact with members of the other group, and were blinded as to the exercise taught to the alternative group. Groups met for 60 minutes 3 times each week. The compliance rate was 90%. Thirty-eight patients completed the study (18 with CVR training and 20 with FLEX). Blind assessments (standardized in preliminary trials to achieve acceptable inter-rater agreement) were performed by the same 2 examiners. After 20 weeks, patients receiving CVR training showed significantly improved cardiovascular fitness scores compared with those receiving FLEX training (t[35] = -4.22, P < 0.003). Logistic regression analysis showed clinically and statistically significant improvements in pain threshold scores, which were measured directly over fibrositic tender points, in patients undergoing CVR (a351 = 2.21, P < 0.04).

Objective. To compare the relative efficacy and tolerability of amitriptyline, cyclobenzaprine, and placebo in the treatment of fibromyalgia, and to identify predictors of response to amitriptyline and cyclobenzaprine.Methods. Two hundred eight patients who fulfilled the American College of Rheumatology criteria for the classification of fibromyalgia were entered into a 6-month prospective, double-blind, multicenter trial and were randomized to 1 of 3 treatment groups: amitriptyline, cyclobenzaprine, or placebo.Results. After 1 month, 21%, 12%, and 0% of the amitriptyline, cyclobenzaprine, and placebo patients, respectively, had significant clinical improvement (amitriptyline versus placebo P = 0.002, cyclobenzaprine versus placebo P = 0.02, amitriptyline versus cyclobenzaprine P not significant). These percentages increased to 36%, 33%, and 19%, respectively, at the 6-month assessment (P not significant). The nature and frequency of side effects reported by patients treated with amitriptyline and those reported by patients treated with cyclobenzaprine were similar. A normal Minnesota Multiphasic Personality Inventory (MMPI) profile at baseline was predictive of clinical improvement at the 1-month evaluation (odds ratio 3.3, 95% confidence interval 1.2-9.0). However, neither the MMPI profile nor any of the demographic, clinical, or functional parameters evaluated at baseline predicted long-term response.Conclusion. Our data confirm the short-term efficacy of amitriptyline and cyclobenzaprine in a small percentage of patients with fibromyalgia. Long-term efficacy could not be demonstrated because of a higherthan-expected placebo response. Predictors of response to these drugs could not be determined.Fibromyalgia is a common condition of unknown etiology, characterized by generalized musculoskeletal pain in association with the presence of multiple tender points at characteristic locations (1,2). Theories about the pathophysiology of fibromyalgia include the interplay of mechanical stresses in the cervical and lumbar spine (1,3), sleep disturbances (1,4,5), psychological factors (H), muscle deconditioning (9), and abnormalities in the function of neurotransmitters (10). Long-term followup of patients