IASP Terminology Background
The following pain terminology is updated from "Part III: Pain Terms, A Current List with Definitions and Notes on Usage" (pp 209-214) Classification of Chronic Pain, Second Edition, IASP Task Force on Taxonomy, edited by H. Merskey and N. Bogduk, IASP Press, Seattle, ©1994.
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The work of the Task Force on Taxonomy in the era of 1979 to 1994 has been continued by the Committee on Taxonomy that has worked to update both pain terms and the classification of pain syndromes. All of the terms have been carefully reviewed and their utility assessed in reference to new knowledge about both clinical and basic science aspects of pain. The Committee conducted its business primarily by e-mail, but face-to-face meetings were held at each of the annual Congresses of IASP. We now present the 2011 version of IASP Pain Terminology. Members of the Taxonomy Committee in this era included: David Boyd, Michael Butler, Daniel Carr, Milton Cohen, Marshall Devor, Robert Dworkin, Joel Greenspan, Troels Jensen, Steven King, Martin Koltzenburg, John Loeser, Harold Merskey, Akiko Okifuji, Judy Paice, Jordi Serra, Rolf-Detlef Treede, and Alain Woda. The Chair would like to acknowledge the continuous contributions that Harold Merskey has made to taxonomy since the founding of IASP. As stated in prior publications of the IASP taxonomy, we do not see this listing of terms as immutable. As we learn more about pain, we will need to update terminology.
John D. Loeser, M.D.
Chair, IASP Terminology Working Group
PAIN TERMS and Definitions
Note: An asterisk (*) indicates that the term is either newly introduced or the definition or accompanying note has been revised since the 1994 publication.
The implications of some of the above definitions may be summarized for convenience as follows:
Allodynia: Lowered threshold - Stimulus and response mode differ
Hyperalgesia: Increased response - Stimulus and response mode are the same
Hyperpathia: Raised threshold: increased response - Stimulus and response mode may be the same or different
Hypoalgesia: Raised threshold: lowered response - Stimulus and response mode are the same
Note: The above essentials of the definitions do not have to be symmetrical and are not symmetrical at present. Lowered threshold may occur with allodynia but is not required. Also, there is no category for lowered threshold and lowered response—if it ever occurs.