Measurement of pain threshold in patients with rheumatoid arthritis, osteoarthritis, ankylosing spondylitis, and healthy controls.

Pain threshold was measured using a pressure algometer in 126 subjects, of whom 54 were females and 72 males. These subjects included 18 males and 18 females with rheumatoid arthritis, 18 males and 18 females with osteoarthritis, 18 males with ankylosing spondylitis, and 18 male and 18 female healthy control volunteers. Six points were studied on each side of the body: 2 cm above the eyebrow on the forehead, lateral aspect of the arm at the insertion of the deltoid muscle, midpoint of the ulna, hypothenar eminence in the palm, midpoint of the quadriceps muscle, and midpoint of the antero-medial aspect of the tibia. None of these points corresponded to the "trigger" points in fibromyalgia. The pain threshold was statistically significantly higher in patients with ankylosing spondylitis than in patients with osteoarthritis, and these in turn were statistically higher than in the normal subjects. Patients with rheumatoid arthritis had significantly lower pain thresholds than the normal subjects. No laterality in pain threshold was identified, but females had in general a lower pain threshold.

Carbamazepine in the dyscontrol syndrome associated with limbic system dysfunction.

The literature has long demonstrated an association between certain behavioral problems and EEG abnormalities, particularly the association of aggressive and sometimes violent behavior with foci in the temporal lobes. The concept of "dyscontrol syndromes" has also been established and it is possible that some instances of the dyscontrol syndrome arise from an abnormal sensitization of the limbic system, due to disturbance in or near the temporal lobes. Carbamazepine is an interesting new drug, with both anticonvulsant and psychotropic properties, for which both the behavioral effects and pharmacological actions have been defined. The properties of carbamazepine for blocking polysynaptic reflexes and suppressing post-tetanic potentiation are discussed with respect to this limbic system dysfunction in the dyscontrol syndrome. It is also proposed that this drug might be considered for its psychotropic effect in certain instances of dyscontrol, with or without clinical diagnosis of epilepsy. An illustrative case is cited.

Fibromyalgia: can one distinguish it from simulation? An observer-blind controlled study.

OBJECTIVE: A randomized controlled trial was conducted to assess reliability and accuracy in identification of fibromyalgia (FM), motivated simulation, and normal controls. METHODS: Eight female subjects with chronic FM were age matched with 19 healthy female volunteers. The volunteers were randomized to a financially motivated "simulator" group who were paid to simulate FM, or to a "normal control" group. Examiners under blinded conditions rated tender and control points, and illness behavior. Intraclass correlation coefficients and F values showed that counts of tender points significantly discriminated the 3 groups. Variance was mostly due to experimental groups and not to observer or error factors. In this study, simulators could not be discriminated from normals or FM subjects on the basis of tenderness at "control points." Examiner ratings of illness behavior (UAB), and subjects' self-ratings for pain showed that FM subjects had the highest scores, normals the lowest, and simulators had mean scores midway between the mean FM and simulator. On grip strength, the normals obtained the highest scores, the simulators the lowest, and the FM subjects had scores midway between those of the other 2 groups. Diagnostic accuracy of the blinded examiners in distinguishing FM from simulators and from normals was 80%, and for correct diagnosis the kappa value was significant at 0.69. Despite this, simulators were misidentified as FM in 1/3 of judgments, and FM was misidentified as simulators in 1/5 of judgments. CONCLUSION: Under randomized blinded conditions, examiners using the American College of Rheumatology criteria for FM and other bedside observations are able to distinguish chronic FM, normal individuals, and motivated simulators with 80% accuracy, with a good level of agreement and reliability in tender point counts. Our results do not provide a "test for malingering," and it is likely that an important minority of motivated simulators and of FM subjects will be misidentified.