UCLA

Studies suggest that patients with chronic pain disorders such as fibromyalgia (FM) develop persistent symptom-specific anxiety from previous threatening stimuli, which may contribute to pain-related symptoms. The aim of this study is to determine if pain and symptom-specific anxiety in FM correlates with an objective, non-invasive index of affective response to specific contexts or stimuli (acoustic startle response [ASR]). Women with FM and healthy women underwent somatic perception testing using a dolorimeter and ASR testing. ASR was measured at: 1) baseline, 2) context and 3 cued threat conditions: 3) safe (no stimulation), 4) anticipation of possible threat, and 5) imminent threat of an aversive somatic stimulus. To maintain anticipation, one moderately intense biceps electrical stimulus was given in the middle of the experiment. Pain severity and pain-related anxiety were measured. Compared to controls, FM patients demonstrated increased somatic pain perception. Both groups showed increasing ASR to progressively increasing threat but there were no group differences. However, in the FM group, pain intensity correlated with ASR to imminent threat (r=0.52, p<0.05) and pain-related anxiety correlated with ASR to anticipated (r=0.61, p<0.01) and imminent threat (r=0.49, p<0.05). Thus, pain-related anxiety and severity were associated with enhanced responsiveness of emotional arousal circuitry in FM.