Unconditioned and conditioned muscular responses in patients with chronic back pain and chronic tension-type headaches and in healthy controls

TY - JOUR

T1 - Unconditioned and conditioned muscular responses in patients with chronic back pain and chronic tension-type headaches and in healthy controls

AU - Klinger, Regine

AU - Matter, Nadia

AU - Kothe, Ralph

AU - Dahme, Bernhard

AU - Hofmann, Ulrich G

AU - Krug, Florian

N1 - Copyright 2010 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

PY - 2010/7

Y1 - 2010/7

N2 - Muscular tension is assigned an important role in the development and maintenance of chronic pain syndromes. It is seen as a psychophysiological correlate of learned fear and avoidance behavior. Basic theoretical models emphasize classical conditioning of muscular responses as a mechanism of pain chronification. However, the empirical basis for this field is very small. Our aim was to investigate muscular factors in relation to unconditioned and conditioned pain stimuli. An experimental study was conducted using a differential classical conditioning paradigm with 18 patients with chronic back pain (BP) and tension-type headache (TTH), and 18 healthy controls (HC). A high-pitched sound served as the CS+, paired with an intracutaneous electric pain stimulus (US), while a neutral sound was used as the CS-. Simultaneously, integrated surface electromyograms (iEMGs) were recorded for seven muscle sites. Our hypothesis was that the pain patients would demonstrate enhanced conditionability. Baseline values between patients (TTH, BP) and HC showed no significant differences. Although the perception and pain thresholds were balanced, both patient groups revealed a higher number of significant muscular responses to the pain stimulus (UR) than the HC. All participants showed significant conditioned muscular responses, however, the patients displayed a higher number than the healthy controls. Furthermore a significant relation was found between muscular responses and the experience of pain 1day after the experiment. Muscular responses can be learned via classical conditioning. TTH and BP patients revealed a higher number of unconditioned and conditioned responses.

AB - Muscular tension is assigned an important role in the development and maintenance of chronic pain syndromes. It is seen as a psychophysiological correlate of learned fear and avoidance behavior. Basic theoretical models emphasize classical conditioning of muscular responses as a mechanism of pain chronification. However, the empirical basis for this field is very small. Our aim was to investigate muscular factors in relation to unconditioned and conditioned pain stimuli. An experimental study was conducted using a differential classical conditioning paradigm with 18 patients with chronic back pain (BP) and tension-type headache (TTH), and 18 healthy controls (HC). A high-pitched sound served as the CS+, paired with an intracutaneous electric pain stimulus (US), while a neutral sound was used as the CS-. Simultaneously, integrated surface electromyograms (iEMGs) were recorded for seven muscle sites. Our hypothesis was that the pain patients would demonstrate enhanced conditionability. Baseline values between patients (TTH, BP) and HC showed no significant differences. Although the perception and pain thresholds were balanced, both patient groups revealed a higher number of significant muscular responses to the pain stimulus (UR) than the HC. All participants showed significant conditioned muscular responses, however, the patients displayed a higher number than the healthy controls. Furthermore a significant relation was found between muscular responses and the experience of pain 1day after the experiment. Muscular responses can be learned via classical conditioning. TTH and BP patients revealed a higher number of unconditioned and conditioned responses.

KW - Analysis of Variance

KW - Back Pain

KW - Conditioning, Classical

KW - Electric Stimulation

KW - Electrocardiography

KW - Electromyography

KW - Humans

KW - Muscle, Skeletal

KW - Pain Threshold

KW - Tension-Type Headache

KW - Journal Article

KW - Research Support, Non-U.S. Gov't

U2 - 10.1016/j.pain.2010.03.036

DO - 10.1016/j.pain.2010.03.036

M3 - SCORING: Journal article

C2 - 20452731

VL - 150

SP - 66

EP - 74

JO - PAIN

JF - PAIN

SN - 0304-3959

IS - 1

ER -