The hypervigilance model of pain perception states that patients with fibromyalgia (FM) have an enhanced sensitivity to aversive and non-aversive stimuli. Few studies have focused on enhanced interoceptive sensitivity in FM. Therefore, the aim of the present study was to investigate spontaneous sensations (SPS) in FM.
SPS are those tingling, tickly and other kind of sensations usually perceived on the skin during periods of rest and without any external trigger. Therefore, we have investigated SPS by requiring participants to focus attention on each hand.
Eighteen patients with a diagnosis of FM and 18 matched healthy participants had to direct their gaze toward the hand tested for a period of 10s. Subsequently, they had to map and report the intensity, the number and the qualitative properties of sensations arising spontaneously. Finally, participants had to fill out questionnaires assessing cognitive and affective status that may influence the interoceptive sensations feedback.
Patients with FM perceived SPS as significantly more intense than controls did. Additionally, SPS were perceived by the FM group as occupying an overall larger area on the hand than those reported by controls. Importantly, entering scores of pain and catastrophism as covariates produced a relative effect on the feeling of SPS.
The outcome of this study supports the generalized hypervigilance model, suggesting that patients with FM have a perceptual style of amplification of non-aversive interoceptive stimulation, modulated by pain and catastrophizing. This is discussed in relationship to interoceptive awareness.