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

BackgroundSelf-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.MethodsFM 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/cm2) 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.ResultsPatients 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.ConclusionsThe 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.

► FM patients have been described as persons with a general increased sensitivity.
► FM patients performed significantly worse in an odor identification test.
► In contrast, they rated their olfactory sensitivity as relatively high.
► These results question the perception of FM patients as multisensory hypersensitive.