Self-ratings of higher olfactory acuity contrast with reduced olfactory test results of fibromyalgia patients

Abstract

Background: Self-reports of fibromyalgia (FM) patients about an enhanced olfactory acuity have been used to characterize them as persons with a general increased sensitivity to sensory input consistent with a central sensitization. However, as reduced activations in some brain areas also seem to accompany FM, a multisensory hypersensitivity is not a necessary consequence.

Methods: FM patients meeting ARA (American Rheumatism Association) criteria (16 women and one man, aged 23-56 years, spontaneous pain 32-91 mm visual analog scale [VAS], 14-18 tender points with a pressure pain threshold of 1.5±0.7 kg/cm(2)) received an olfactory test (Sniffn' Sticks) to assess their odor thresholds to n-butanol and their ability to discriminate and identify odors. Healthy controls were 14 age-matched women and one man.

Results: Patients had poorer odor identification than controls (14.6±1.3 vs. 15.5±0.6; p<0.05) but did not differ in odor thresholds or odor discrimination. This test result contrasted with the patients' self-ratings of their olfactory sensitivity as higher than average.

Conclusions: The perception of FM patients as being multisensory hypersensitive is not supported by present results. In contrast to the subjects' self-ratings, measurements of olfactory function showed a slightly reduced odor identification, with a by-and-large normal performance.