Quantitative sensory testing in fibromyalgia and hemisensory syndrome: comparison with controls

Fibromyalgia syndrome (FS) is a chronic painful condition with sensory, motor and affective dysfunctions. Few studies had investigated the trigeminal area, and little is known about its association with hemisensory syndrome, which is characterized by chronic pain restricted to hemibody. Our objective was to investigate sensorial abnormalities with quantitative sensory testing of patients with FS and patients with hemisensory syndrome, compared to controls. Thirteen patients diagnosed with FS according to the American College of Rheumatology, and 12 patients with hemisensory syndrome were evaluated and compared to 25 age-gender-matched controls. They were investigated with a quantitative sensory testing protocol including gustative, olfactory, cold, warm, touch, vibration, electric, deep and superficial pain thresholds and the corneal reflex evaluation. The patients had higher gustative thresholds for salty and bitter. In general, patients with FS had somatosensory thresholds higher than the controls; however, patients with hemisensory syndrome had only superficial pain thresholds increased, in both body sides and not only in the area affected by pain. Patients with hemisensory syndrome can be a subgroup of FS, different from nondermatomal somatosensory deficits which are characterized by chronic pain with hypoesthesia in hemibody. The bilateral hypoalgesia supports that pain pathways play a key role in this condition, with no compromise of other sensorial modalities.