Central Hyperexcitability in Fibromyalgia

SUMMARY

Hyperalgesia to pressure stimuli combined with spontaneous muscle pain are present in fibromyalgia [FMS]. If increased responses to painful stimuli are found in muscles without spontaneous pain, it could indicate involvement of central hyperexcitability in FMS. In the present study, experimental painful stimulation of a pain-free muscle in FMS patients resulted in exaggerated referred pain patterns compared to controls. Moreover, repeated painful electrical muscle stimulation caused facilitated pain in FMS patients compared to controls [i.e., increased gain of temporal summation]. Temporal summation of skin stimuli above the painful muscle was not affected. These findings probably reflect involvement of central hyperexcitability [muscular hyperalgesia] in the FMS patients.

KEYWORDS:

• Muslce
• pain
• central sensitization
• saline injection