Objective: To determine perception and pain thresholds in patients with fibromyalgia syndrome and in healthy controls, and to investigate whether patients with fibromyalgia syndrome can be grouped with respect to thermal hyperalgesia and whether these subgroups differ from healthy controls and in clinical appearance.
Design: The authors conducted a quasi-experimental clinical study.
Subjects: Twenty-nine women patients with fibromyalgia syndrome and 21 healthy pain-free age-matched women participated in the study.
Methods: Quantitative sensory testing using a Thermotest instrument was performed on the dorsum of the left hand. Sleep and pain intensity were rated using visual analog scales.
Results: Cold and heat pain but not perception thresholds differed significantly between patients with fibromyalgia syndrome and healthy subjects. Based on thermal pain thresholds, two subgroups could be identified in fibromyalgia syndrome using cluster analysis.
Conclusion: Patients with fibromyalgia syndrome were subgrouped by quantitative sensory testing (i.e., thermal pain thresholds). Subgroups show clinical differences in pain intensities, number of tender points, and sleep quality. Cold pain threshold was especially linked to these clinical aspects.
Departments of *Medicine and Care, Pharmacology, and †Neuroscience and Locomotion, Rehabilitation Medicine, Faculty of Health Sciences, Linköping, Sweden
Received July 18, 2000;
final revision June 26, 2001; accepted July 17, 2001.
The study was supported by grants from the county of Östergötland, Sweden.
Address correspondence and reprint requests to Ingrid Hurtig, Department of Medicine and Care, Pharmacology, Faculty of Health Sciences, SE 581 85 Linköping, Sweden; e-mail: firstname.lastname@example.org