[P02.112] Presence of Conditioning Pain but Not Its Degree or Modality Determines DNIC Extent

David Yarnitsky, Yonatan Crispel, Dorit Pud, Irit Weissman-Fogel, Michal Granot, Haifa, Israel

OBJECTIVE: This study aimed to evaluate the association between parameters of the conditioning stimulus, gender as well as personality variables and the diffuse noxious inhibitory control (DNIC) response. BACKGROUND: Mechanisms of descending modulation of pain, demonstrated by psychophysical tests applying dual pain stimulation, are now more commonly explored. Yet, basic facts about these test paradigms are still open. DESIGN/METHODS: Contact heat pain was applied as conditioned stimulus (30) to the non-dominant forearm in 31 healthy volunteers. Stimulation temperature was administered at psychophysical intensity scoring 60 on a 0-100 numerical pain scale. The conditioning stimulus was a one-minute immersion of the dominant hand in cold (12C, 15C, 18C), hot (44C and 46.5C) or skin temperature (33C) water. The conditioned stimulus was repeated at the non-dominant hand, during the last 30 of the conditioning immersion. DNIC extent was calculated as the difference between pain scores in response to conditioned contact stimulus before and during hand immersion. State and trait anxiety, and pain catastrophizing scores were assessed before the subjects were exposed to the painful tests. RESULTS: Presence of pain experience due to the conditioning stimulus was required in order to induce DNIC, demonstrated only for 46.5 and 12C conditioning stimuli (p<0.0018 and 0.0005 respectively). The pain scores of the conditioning stimuli, however, were not correlated with DNIC extent. Significant gender effect was found with greater DNIC response in males (p=0.012), but no effect of the conditioning pain modality (cold or hot pain) or personality. CONCLUSIONS/RELEVANCE: These findings put forward DNIC testing, being relatively independent of the testing conditions and of psychological state, as a solid test with potential for becoming a widely used measure in the clinical pain testing setup.
Category - Peripheral Nerve
SubCategory - Other

Tuesday, May 1, 2007 11:30 AM

Poster Sessions: Peripheral Nerve: Diabetic Neuropathy and Pain (11:30 AM-2:30 PM)

The embargo for all abstracts to be presented at the 59th Annual Meeting is in effect until the date and time of the presentation unless otherwise noted on the abstract and/or press release. If there are questions, please contact the AAN media and public relations team.