Somaesthetic disturbances in fibromyalgia are exaggerated by sensory-motor conflict: implications for chronicity of the disease?

Objectives. Conflict between sensory-motor central nervous processing generates somaesthetic disturbances, including pain, in healthy volunteers (HVs). Such conflict has been proposed as a potential cause of pain that occurs in the absence of injury or when the pain response is disproportionate to the injury. Fibromyalgia (FMS) exemplifies the former state. We hypothesized that the artificial generation of such conflict would exacerbate somaesthetic perceptions including pain in FMS greater than in HVs. Methods. Twenty-nine adults with FMS took part in an established task that generates varied degrees of sensory-motor conflict during congruent/incongruent limb movements. A qualitative methodology recorded any changes in sensory experience. Data generated were compared with age and gender-matched HV data. Results. Twenty-six subjects (89.7%) with FMS reported changes in sensory perception at some stage in the protocol in addition to, or worse than, baseline compared with 14 (48%) of HVs. All stages of the protocol generated a higher frequency of report in the FMS population than that of the maximum report in the HVs population. New perceptions included disorientation, pain, perceived changes in temperature, limb weight or body image. Conclusions. Our findings support the hypothesis that motor-sensory conflict can exacerbate pain and sensory perceptions in those with FMS to a greater extent than in HVs.