Do fibromyalgia patients display hypervigilance for innocuous somatosensory stimuli? Application of a body scanning reaction time paradigm.

This study tested the hypothesis that fibromyalgia patients display hypervigilance for somatosensory signals. Hypervigilance was operationalized as the detection of weak electrocutaneous stimuli. Innocuous electrical stimuli gradually increasing in strength were administered to one of four different body locations. A reaction time paradigm was used in which subjects had to respond as fast as possible to stimulus detection by pressing a button corresponding to the correct body location. The detection task was presented first under single task conditions and subsequently under dual task conditions, in combination with a second (visual) reaction time task. It was predicted that hypervigilance would be most prominent under dual task conditions, where subjects can choose to allocate attention selectively to one of the tasks. Questionnaires on general body vigilance, pain vigilance, pain related-fear and pain catastrophizing were also administered. Thirty female fibromyalgia patients were compared to 30 healthy controls matched on age, sex and educational level. No evidence for hypervigilance for innocuous signals was found: patients did not show superior detection of electrical stimuli either under single or dual task conditions. Also, no differences were found between patients and controls on the body vigilance questionnaire. Detection of electrical stimuli was, however, predicted by pain-related fear and pain vigilance.